Diavel suspension is too firm

[jamjam]

I just traded a Ducati Monster for a Diavel and finding the suspension on the Diavel is really firm. I have made many tweaks as per the owner's manual and the best I have found is backing everything off (comp and reb) to their softest setting (front and rear) and then winding the rear preload right up to the maximum. I found this suggestion on another forum. This is the best I can get the bike to feel but it is still very harsh over every little bump on the road and motorway. It is cornering great on a smooth surface but imperfactions on back roads does cause it to "skip" on the corner. Basically it is not compliant and it feels like the high speed compression is non existent and it's like riding on a wooden plank with no suspension each time you hit any little (and I mean little) imperfection in the road. I weigh 83kg geared up so I am in the sweet spot of 80-90kg according to the manual.

Is this normal for this bike and has anyone else experienced this on the Diavel and found solutions around it... do I need to fork out for an Ohlins or does it sound like the shock is faulty? The bike has only done 300km but gut feel is this harshness may not improve with wearing in.

[jellywrestler]

The bike has only done 300km but gut feel is this harshness may not improve with wearing in.

I got a Gut Felling once when I was having sex with a woman that had had her uterus surgically removed....

[SVboy]

I know nothing of Diavel suspension but this does not sound like the way forward. Having the preload wound up will make the bike very firm over bumps but the lack of rebound control could see you thrown out of your seat if you hit a really sharp bump. I would suggest at least setting the sags to your weight-see Utube= and returning the clickers to factory positions, and playing from there. If it is truly bad, take it to a suspension specialist who may respring it for your weight and revalve the shock and forks to be more compliant on NZ roads.

[Cosmik de Bris]

I just traded a Ducati Monster for a Diavel and finding the suspension on the Diavel is really firm. I have made many tweaks as per the owner's manual and the best I have found is backing everything off (comp and reb) to their softest setting (front and rear) and then winding the rear preload right up to the maximum. I found this suggestion on another forum. This is the best I can get the bike to feel but it is still very harsh over every little bump on the road and motorway. It is cornering great on a smooth surface but imperfactions on back roads does cause it to "skip" on the corner. Basically it is not compliant and it feels like the high speed compression is non existent and it's like riding on a wooden plank with no suspension each time you hit any little (and I mean little) imperfection in the road. I weigh 83kg geared up so I am in the sweet spot of 80-90kg according to the manual.

Is this normal for this bike and has anyone else experienced this on the Diavel and found solutions around it... do I need to fork out for an Ohlins or does it sound like the shock is faulty? The bike has only done 300km but gut feel is this harshness may not improve with wearing in.

Preload doesn't alter the spring force so should be set so that the travel of the suspension is correct. The damping settings can make the suspension seem hard. If there is too much compression then the suspension doesn't go down fast enough and with too much rebound the suspension will stay down too long. If you have these correct then the only thing you can do is replace the springs.

Cheers

[jamjam]

Yeh i tried factory comp and reb settings first on "Standard" with 0 preload on the rear. I then tried on "comfort" settings with 0 preload and it was still really really bad. The manual calls for 0 preload unless for sport setting or with a passenger. I tweaked the settings around this but the harshness is always there. I spent about 2 hrs going back and forth through the same corners and bumps with a screwdriver tampering with settings. I then tried a drastic approach of back everything right off and raise the rear preload to max. This is about as best as I can get it to feel but it's still really harsh and of course I shouldn't have to have the preload all the way up. The geomery of the bike like this is good (ie turn in etc) I am not sure if I was bottoming out the shock before or not. Over long undulations in the road the suspension flows with it but any little bumps in the road are jarring and sudden through the bike... like it's bottoming out the shock instantly or has no high speed compression control at all. I could be way off whack on what the problem is so just wondering if anyone else out there has come across this on a Diavel.

I am thinking of putting it into a suspension specialist to see what they can come up with but not sure who is a good one or preferably one that has worked on a Diavel before and seen this problem or these symptoms.

[iYRe]

have you checked out feelthetrack.com ? lots of good info and videos on suspension settings

[Autech]

I just traded a Ducati Monster for a Diavel and finding the suspension on the Diavel is really firm. I have made many tweaks as per the owner's manual and the best I have found is backing everything off (comp and reb) to their softest setting (front and rear) and then winding the rear preload right up to the maximum. I found this suggestion on another forum. This is the best I can get the bike to feel but it is still very harsh over every little bump on the road and motorway. It is cornering great on a smooth surface but imperfactions on back roads does cause it to "skip" on the corner. Basically it is not compliant and it feels like the high speed compression is non existent and it's like riding on a wooden plank with no suspension each time you hit any little (and I mean little) imperfection in the road. I weigh 83kg geared up so I am in the sweet spot of 80-90kg according to the manual.

Is this normal for this bike and has anyone else experienced this on the Diavel and found solutions around it... do I need to fork out for an Ohlins or does it sound like the shock is faulty? The bike has only done 300km but gut feel is this harshness may not improve with wearing in.


Yeh i tried factory comp and reb settings first on "Standard" with 0 preload on the rear. I then tried on "comfort" settings with 0 preload and it was still really really bad. The manual calls for 0 preload unless for sport setting or with a passenger. I tweaked the settings around this but the harshness is always there. I spent about 2 hrs going back and forth through the same corners and bumps with a screwdriver tampering with settings. I then tried a drastic approach of back everything right off and raise the rear preload to max. This is about as best as I can get it to feel but it's still really harsh and of course I shouldn't have to have the preload all the way up. The geomery of the bike like this is good (ie turn in etc) I am not sure if I was bottoming out the shock before or not. Over long undulations in the road the suspension flows with it but any little bumps in the road are jarring and sudden through the bike... like it's bottoming out the shock instantly or has no high speed compression control at all. I could be way off whack on what the problem is so just wondering if anyone else out there has come across this on a Diavel.

I am thinking of putting it into a suspension specialist to see what they can come up with but not sure who is a good one or preferably one that has worked on a Diavel before and seen this problem or these symptoms.

I rode a two different Diavels in Canada and they both had a rather harsh ride now that I think of it, didn't bother me too much as I was used to my gixxer.
One of them had been taken to a suspension guy though and was definitely loads better turning in than the other which was set to the stock settings. I'd suggest going back to the dealer and see if their mechanic can dial it in for your weight better, if not go see a guru who'll get it working for you.

All this aside, how fucking good is the engine? Put it in sport mode and lay black lines :Punk:

[jamjam]

The motor is pretty sweet indead, i gave the demo bike the beans in touring mode but didn't try sport mode... Once mine is run in i'll have to try that out :banana:

I am wondering if I missed the firmer suspension on the demo given half the time was with the misses on the back. It does have a sports bike feel to the suspension, perhaps a wee bit firmer but less compliant so maybe that's just the way they are... thankfully half of my riding is lane splitting the motorway and the other half is a weekend blast or tour - sometimes with the cook on the back. Compared to the Monster I wasn't expecting a harsh ride, the Monster was nice and I thought the Diavel would be similar or smoother.

I think you are right and the next best step would be to take it back and use the dealer's facilities to measure and dial in the SAG for me. I guess unless they spot something wrong with it then I probably have to accept that it's just the type of bike it is. I could still go the Ohlins path if I have to because another forum said that it made the ride much better but I would kick myself if it was still a hard ride after spending the money.

[merv]

Winding the preload all the way up is only going to make the bike feel stiffer and did you not try taking the preload the other way to soften it or we at crossed purposes here and when you say winding it up are you meaning in the softer direction?

[Autech]

Winding the preload all the way up is only going to make the bike feel stiffer and did you not try taking the preload the other way to soften it or we at crossed purposes here and when you say winding it up are you meaning in the softer direction?

Plus taking off preload lowers your ride height :third:

[Mike.Gayner]

Increasing preload doesn't stiffen the bike, and decreasing preload doesn't soften the bike.

[jamjam]

Initially the preload was right down to soft, so lowering the bike. That is the factory setting according to the owners manual. This is how I had it for the first 2 hours. I then tried it on 7 clicks (10 clicks is sport setting) and then 20 clicks and then up near max at 40 clicks - so as high as it goes.

The compression and rebound were both at standard settings front and rear which is about 1/3 dialing back from hard. I then tried on comfort setting so about 3/4 towards soft (ie really soft compression and not much rebound damping to keep it higher in the stroke).

Adding more preload to the rear would improve the harshness each time so it seemed like the right direction to go in. I then tried more compression with this and it got worse again so I backed off the compression towards soft. The more I could keep the suspension up in it's soft region of the suspension the better it was and then only preload seemed to compensate for this.

The bike only has 4" of suspension travel so maybe I only have a small window to find that sweet spot between weight (with preload getting the SAG right) and compression/rebound after that. Perhapd I missed that window altogether. I have left a message with the bike shop mechanic to call me to see if he knows of a good starting point to help me tune this bikes in.

[Crasherfromwayback]

Increasing preload doesn't stiffen the bike, and decreasing preload doesn't soften the bike.

Not quite correct.

[jamjam]

Does anyone know a good bike suspension specialist in Auckland that can set the SAG and fine tune the settings to my weight?

[SVboy]

Can I suggest KSS aka Robert Taylor in New Plymouth? Call him, book in, ride down, get job done, cruise home and love the difference. Take a big cheque book, but well worth it. I doubt the Diavel was peanuts to start with.......

[nzspokes]

Measure the sag yourself. https://www.youtube.com/watch?v=FjGgq1z9zbo

Sounds like you are blasting through the travel but sag will tell you this. Comp and rebound all the way out may be making it worse.

Let us know the sag numbers.

[jamjam]

I tried settings at "sport" and really there's not much in it and it's also harsh. I thought maybe with settings at soft end it was bottoming out but still the same whether i set for soft or set for hard.

BTW I should point out I've owned a few bikes and dirt bikes so I understand how to make changes on suspension. Ie rebound damping = speed of return, softer (more turns counter) meaning rebounds faster and sits higher in the stroke where the suspension is generally softer.

I measured rider sag when I got home at 20mm without gear so with gear and bag it's prob 23mm. Screaming kids to get to bed so no time to kit up or screaming wife as well :facepalm:

This was with rear preload at 25 clicks so about half way on adjuster which is "sport" setting per manual. I think I should have researched more and would have been nice if dealer told a good returning customer that it will be firmer and not as comfortable on the back roads as the Monster... but I guess that's what makes me a good customer!!! :weird:

Research seems to point to an ohlins as the solution so there goes my savings for buying on a runout special.

[nzspokes]

As SVBoy said, contact Robert Taylor. He may well be able to sort this much cheaper than a new Ohlins.

[jamjam]

Yep I'm gonna call Robert Taylor tomorrow and see what he reckons is the best way to go. It's a great bike so I only have to get the ride compliant over bumps and take away most of the jarring to get the best out of it.

[ellipsis]

nobody reply to that twat please

[jamjam]

nobody reply to that twat please

Hey mate I only put it out there to see if others had found the same thing with this bike and what solutions they had come up with. Thanks to those who have provided some useful posts and suggestions.

[nzspokes]

Hey mate I only put it out there to see if others had found the same thing with this bike and what solutions they had come up with. Thanks to those who have provided some useful posts and suggestions.

Pretty sure he meant Cassina, not you.

Let us know how you get on with RT.

[ellipsis]

Pretty sure he meant Cassina, not you.



...yeah...but don't encourage any more wank from it...

[Bass]

It's been said about 3 times already in this thread but the message still slides by.
Unless the bike has a rising rate linkage, adjusting the preload has NO effect on suspension stiffness. It only adjusts the ride height.
It's purpose is to keep the suspension in its "sweet" range with varying loads aboard.

If the bike does have a rising rate linkage, the (badly named) preload adjustment has exactly the reverse effect to what would be instinctively expected.

The O.P. appears to have the beginnings of a grasp on this but hasn't quite thought it right through yet. No-one has mentioned tyre pressures either.

[Crasherfromwayback]

It's been said about 3 times already in this thread but the message still slides by.
Unless the bike has a rising rate linkage, adjusting the preload has NO effect on suspension stiffness. It only adjusts the ride height.
It's purpose is to keep the suspension in its "sweet" range with varying loads aboard.

.

That's not actually quite correct. In theory, it should be, but in practice, it's not. Preload does have an effect on roughly the first third of the suspension movement. Try a moto-x bike with absolutely no sag at all, vs one with 100mm of sag. The diff is huge.

[Bass]

That's not actually quite correct. In theory, it should be, but in practice, it's not. Preload does have an effect on roughly the first third of the suspension movement. Try a moto-x bike with absolutely no sag at all, vs one with 100mm of sag. The diff is huge.

But an MX bike will have a linkage which is likely highly rising rate. KTM graphs for their old 640 Adventure showed suspension travel to wheel travel relativity that went from 0.9 when extended to over 4 when compressed. So you would expect the suspension to appear to harden up dramatically from no sag to 100 mm.

Note what I said here - you backed off the preload (more sag) but the suspension appeared to harden up because the damper was travelling faster. Further, it's all damper effect - the spring has nothing to do with it. Move the wheel very slowly in both positions so the damper effect is nil and you will see no difference between them.

Like I said, the point of preload is to put the suspension into its sweet spot

[Crasherfromwayback]

But an MX bike with will have a linkage which is likely highly rising rate. KTM graphs for their old 640 Adventure showed suspension travel to wheel travel relativity that went from 0.9 when extended to over 4 when compressed. So you would expect the suspension to harden up dramatically from no sag to 100 mm.

Doesn't actually matter what type of rear suspension you have. My twin shock RM400T VMX bike is exactly the same. if it has absolutely no sag at all, it's a completely diff bike to one with the correct amount of sag. So saying preload has no effect on the suspension is not factually correct.

[jamjam]

Bass has a good point, when i back off the preload it does get firmer. On another forum the guys were saying wind the preload up to max (as high as it goes) and this is as best they can get it. I tried that and indead the suspension feels like it's working more and being more compliant when the preload is up at maximum. To compensate you then soften comp and rebound to their "softest" settings. Despite this being the best I could get it, it was still harsh and unforgiving on any little bump in the road.

I am a confident rider (but I wouldn't say advanced rider because I don't race) and the lack of compliance and skipping on a bumpy corner is tolerable to me in the dry but I suspect it will be dangerous and butt clenching in the wet. That aswell as the lack of comfort factor and the fact I changed from the Monster 1200 to the Diavel to get more upright because of a neck injury (cart wheeled a dirt bike) that was being aggravated by the riding position so i really don't need my neck being jolted constantly too.

BTW I am running 36/36 psi front/rear cold. I could go lower to say 34 at the expense of squaring the rear on the motorway.

To this end I have called Robert Taylor and he knows exactly the problem and said he's installed Ohlins in many many Diavels to fix this issue and make the bike good for our roads. So more stock is expected in a few weeks and then I'll head down to New Plymouth and get it fitted by the experts :niceone:

I have been reading the Diavel forum and so many people have said the bikes are too firm and harsh and fitting an Ohlins has transformed the bike's suspension to awesome.

[Bass]

Doesn't actually matter what type of rear suspension you have. My twin shock RM400T VMX bike is exactly the same. if it has absolutely no sag at all, it's a completely diff bike to one with the correct amount of sag. So saying preload has no effect on the suspension is not factually correct.

Pete, firstly, I have to admit that I'm not familiar with the model, but if the shocks are leaned forward significantly, then that's the way the first rising rates were done.

Secondly, I never said it had no effect on the suspension - I said that in the absence of rising rate, it had no effect on the suspension stiffness (which is what this thread is all about). I stand by that.

I am not an MX'r in any way shape or form, but I expect that big changes to the rear end ride height would markedly affect the handling

[Bass]

BTW I am running 36/36 psi front/rear cold. I could go lower to say 34 at the expense of squaring the rear on the motorway.


I have been reading the Diavel forum and so many people have said the bikes are too firm and harsh and fitting an Ohlins has transformed the bike's suspension to awesome.

Those tyre pressures don't seem excessive to me and am pleased to hear you have a solution, albeit an expensive one.

[Mike.Gayner]

So saying preload has no effect on the suspension is not factually correct.

Wow big shifting goalposts there - who ever said preload has no effect on suspension?

[Crasherfromwayback]

Increasing preload doesn't stiffen the bike, and decreasing preload doesn't soften the bike.


, adjusting the preload has NO effect on suspension stiffness. r.


Wow big shifting goalposts there - who ever said preload has no effect on suspension?

That's how I read these.

[Mike.Gayner]

English as a second language is tough, you'll get there.

[Crasherfromwayback]

English as a second language is tough, you'll get there.

Think you'll find my grasp of the English language is better than your grasp of suspension.

[Bass]

Come on guys - a technical debate is cool and sometimes we even learn something. I did. I'm intrigued by Pete's comments about just how much difference to the handling it makes. I'd like to find out what else is happening there
Letting it descend into personal insults makes it just a pissing contest

Ah shit! Sorry, I forgot. This is K B - no adults allowed

[Crasherfromwayback]

Come on guys - a technical debate is cool and sometimes we even learn something.t

We have a reg customer here, who road races an R6. Was complaining of the handling. It turns up here, with no sag whatsoever, stiff as a board. Back the shock preload off, give it some sag, and viola. Traction and suspension compliance. Because...it's softer. Obviously on big hits, it makes no diff whatsoever, as that's only spring rate as you've pointed out. But my point is, backing off the preload, most def makes the first third (or thereabouts) of the susp softer.

[SVboy]

Nice to see the OP has a way through this. DMTD on this forum had a Diavel and rated it as an excellent and very well handling bike.

[Crasherfromwayback]

DMTD on this forum had a Diavel and rated it as an excellent and very well handling bike.

Yep. I've ridden a couple and they're great. Handle way better than you'd think or expect. A little lazy in the steering, but fun.

[Bass]

We have a reg customer here, who road races an R6. Was complaining of the handling. It turns up here, with no sag whatsoever, stiff as a board. Back the shock preload off, give it some sag, and viola. Traction and suspension compliance. Because...it's softer. Obviously on big hits, it makes no diff whatsoever, as that's only spring rate as you've pointed out. But my point is, backing off the preload, most def makes the first third (or thereabouts) of the susp softer.

Genuine question - was that static sag (bike only) or sag with bike plus rider?

I've seen this sort of thing once or twice before. Too much preload and the shock was topping out on the rebound and was wondering if it could be the same thing. Decreasing the preload didn't actually soften the suspension but it felt that way.

[SVboy]

We have a reg customer here, who road races an R6. Was complaining of the handling. It turns up here, with no sag whatsoever, stiff as a board. Back the shock preload off, give it some sag, and viola. Traction and suspension compliance. Because...it's softer. Obviously on big hits, it makes no diff whatsoever, as that's only spring rate as you've pointed out. But my point is, backing off the preload, most def makes the first third (or thereabouts) of the susp softer.

My understanding of this is rudimentary to say the least but the spring , unless progressively wound remains a constant?The spring never becomes softer or harder itself.Therefore reducing preload reduces the force needed for a bump to make the spring react and conversely more preload requires more force for the spring to react to a bump. Compression controls softness/ firmness, but looking at what I just wrote it looks like preload and compression would act in tandem to control the level of softness/firmness? Could this reult in somebody with too high a spring rate or too much preload trying to compensate with too little compression or the reverse?

[Bass]

The spring never becomes softer or harder itself.Therefore reducing preload reduces the force needed for a bump to make the spring react and conversely more preload requires more force for the spring to react to a bump. ?

This is the commonest misconception. To increase or decrease the spring reaction, you need to compress it or lengthen it. Preload does neither - it just raises or lowers the swing arm. The spring stays the same length.

Your comments about the spring properties and compression damping look OK though and the comment about the wrong spring rate shows real insight. It's common for people to try and correct for the wrong spring rate by fiddling with the damping, but then its much easier than changing the spring.

[SVboy]

This is the commonest misconception. To increase or decrease the spring reaction, you need to compress it or lengthen it. Preload does neither - it just raises or lowers the swing arm. The spring stays the same length.

Your comments about the spring properties and compression damping look OK though and the comment about the wrong spring rate shows real insight. It's common for people to try and correct for the wrong spring rate by fiddling with the damping, but then its much easier than changing the spring.

I struggle with preload affecting ride height as surely that would affect geometry and could be potentially dangerous? For example, winding in a lot of preload at the rear, steepening the front steering angle and making the bike unstable? Certainly adding or removing preload changes at what point in its stroke the spring will react to a bump.

[Bass]

I struggle with preload affecting ride height as surely that would affect geometry and could be potentially dangerous? For example, winding in a lot of preload at the rear, steepening the front steering angle and making the bike unstable? Certainly adding or removing preload changes at what point in its stroke the spring will react to a bump.

Go and have a look at your bike - you will see what I am saying almost immediately. Also the point of preload is to get your suspension back where it should be when you add or remove weight - so it's intended to keep your steering head angle the same.
Yes, changing the preload changes the rest position of the shock and so it changes the start position for any movement. Preload gets you back to the same start point when you change the load that the bike is carrying.

To take this a bit further and to expand on your comments on spring rate, when I add the wife to the beemer and select the appropriate electronic suspension setting, it actually applies preload to raise the bike above where it would be with just me on it. This is because it recognises that the spring rate is set for just the rider and so when a pillion is added the spring is not stiff enough. So it arranges for more travel on the compression stroke and changes the damping rates accordingly.
Yes, it's a compromise, but changing the spring when I add a pillion is a bit tricky.

[Mike.Gayner]

This is the commonest misconception. To increase or decrease the spring reaction, you need to compress it or lengthen it. Preload does neither - it just raises or lowers the swing arm. The spring stays the same length.

Of course preload compresses the spring - that's the entire point of it. By what mechanism do you propose preload raises and lowers the swing arm?


I struggle with preload affecting ride height as surely that would affect geometry and could be potentially dangerous? For example, winding in a lot of preload at the rear, steepening the front steering angle and making the bike unstable? Certainly adding or removing preload changes at what point in its stroke the spring will react to a bump.

This is precisely what altering preload does. You compress the spring without changing the length of the shock - it therefore takes more weight to make the bike sag by the same amount. So for the same given weight, more preload means a higher ride height.

[Cosmik de Bris]

At first I said that preload has no effect on softness or hardness of suspension. I thought about it and of course I WAS WRONG.

F=kX is Hook's law this tells you that to first order at least a spring with constant pitch is linear. k is the spring constant and X is the displacement of the spring. The spring constant k can only be changed by cutting or lengthening.

If you apply a force to the spring to move it X distance it should be obvious that at that distance the spring has a restoring force that is equal. If you preload the spring, which is a change of X you will have a restoring force of kX. The spring constant is k and is constant for this kind of spring, and is referred to as stiffness, this is important because the term stiffness can be misinterpreted. The upshot is that preloading a spring means that you have to overcome the restoring force in order to compress the spring, which in turn means it's going to take more force to start the spring moving i.e. it will seem harder.

That's what I think anyway.

[Crasherfromwayback]

That's what I think anyway.

I have a rear shock out of a 1998 CR250 here for a rebuild. If I wind the preload collars right off, I can compress the shock myself (a wee bit only) by just pushing down on it. If I was to wind the collars right up, I couldn't budge it no matter how hard I might try. So it's softer one way, and harder the other. So for people to say preload makes no diffence to how the shock/bike behaves, and is no softer or stiffer is simply not correct.

[Cosmik de Bris]

At first I said that preload has no effect on softness or hardness of suspension. I thought about it and of course I WAS WRONG.

F=kX is Hook's law this tells you that to first order at least a spring with constant pitch is linear. k is the spring constant and X is the displacement of the spring. The spring constant k can only be changed by cutting or lengthening.

If you apply a force to the spring to move it X distance it should be obvious that at that distance the spring has a restoring force that is equal. If you preload the spring, which is a change of X you will have a restoring force of kX. The spring constant is k and is constant for this kind of spring, and is referred to as stiffness, this is important because the term stiffness can be misinterpreted. The upshot is that preloading a spring means that you have to overcome the restoring force in order to compress the spring, which in turn means it's going to take more force to start the spring moving i.e. it will seem harder.

That's what I think anyway.

I think I'm wrong again. The force to move the spring a unit length is constant, so it shouldn't seem harder. Will someone release me from this hell!

[Crasherfromwayback]

I think I'm wrong again. The force to move the spring a unit length is constant, so it shouldn't seem harder. Will someone release me from this hell!

LOl. Yeah, a 50kg spring, is a 50kg spring. NOTHING changes that. But see my post above yours.

[Autech]

I struggle with preload affecting ride height as surely that would affect geometry and could be potentially dangerous? For example, winding in a lot of preload at the rear, steepening the front steering angle and making the bike unstable? Certainly adding or removing preload changes at what point in its stroke the spring will react to a bump.

Took some preload out of my TZR/FXR bucket setting it to the "recommended" bike + rider static sag and went out for a few laps.
Was peg down on the first corner I went around with cold slicks... Lets just say I went back to the pits and wound that bitch right up again

Pre-load is just that, it's what we do when we go out for a night on the town, we load ourselves up with piss but we still only have the same amount of stomach to contain it :apint:.

[Autech]

I have a rear shock out of a 1998 CR250 here for a rebuild. If I wind the preload collars right off, I can compress the shock myself (a wee bit only) by just pushing down on it. If I was to wind the collars right up, I couldn't budge it no matter how hard I might try. So it's softer one way, and harder the other. So for people to say preload makes no diffence to how the shock/bike behaves, and is no softer or stiffer is simply not correct.

Exactly, I'm guessing it's down to the sprung forces (I'm shit with this stuff), the more it's compressed the more force it is pushing out, therefore you could say that it's harder because the force it's pushing out is more. Actions, reactions, stuff... I'll revert to my real job now: Have you tried turning it off and on again?

[Crasherfromwayback]

Genuine question - was that static sag (bike only) or sag with bike plus rider?

I've seen this sort of thing once or twice before. Too much preload and the shock was topping out on the rebound and was wondering if it could be the same thing. Decreasing the preload didn't actually soften the suspension but it felt that way.

Static sag. As a point regarding stiffness, the R6 was sitting totally at the top of it's travel, and when being ridden over small bumps at low speed, it felt rigid, like it was coil bound. Back it off, give it some static sag, and it's soft enough to absorb those same bumps. It'll still only take the same force to bottom the shock out, so it's obviously not making it softer all the way through the stroke, but the first 1/3 odd of the travel? Hell yes.

[SVboy]

Thank you team, I can see where you are coming from with preload changing ride height.

[Crasherfromwayback]

Thank you team, I can see where you are coming from with preload changing ride height.

Most def. Very important. On my RS250, even a few mm's would change things quite a bit. The model after mine, had the single sided swing arm and an eccentric cam, chain adjuster. So every time you adjusted chain tension, your ride height settings went out the window as well. Pain in zee backside.

[MD]

This discussion is bouncing all over the place. You all need to dampen down your tone so we can rebound back to the topic in question - a sore bum. The first thing that springs to mind whenever I hear people bleating on about their bike needs this and that done to their suspension is; are you really pushing your bike to the limits to warrant spending heaps of $$$ on a luxury you may never actually benefit from. I've met so many riders who obsess with suspension tuning yet ride like a big blouse, too scared to rev beyond idle and no idea why bike tyres have tread on the sides. Never pushed their suspension anywhere near it's limitations.

Sounds like the OP is concerned about bum comfort. Deflate your tyres or sit on a sheepskin rug.

In saying that it is ironic that for the first time in decades I'm changing my current bikes shock for a better one. But that is after 3 months of serious hard riding to get to know it and too many scary moments that have convinced me I'm playing Russian roulette.

If you ride heaps and it does sound like you have tried all possible variations with the OEM then yeah, change bikes or change the suspenders.

Apologies if it sounds like I did some preloading before writing this.

[Crasherfromwayback]

Apologies if it sounds like I did some preloading before writing this.

Makes perfect sense to me.

330863

[BMWST?]

here is my take on it.You cant"preload" the spring.You wind up the preload and you are trying to push the top of the spring up.There is no extra force to push the spring down so the rear of the bike raises by 5mm or whatever.And another 5mm next time ....and so on.However there is a limit to that travel,and it is the length of the shock itself.Not sure but i guess the the logical end of the preload adjustment wwould actually have the shock topped right out.Preload is never a term i could figure..its ride height adjuster.It also steepens the head angle and alters the geometry of the rear suspension a little bit.
Springs are a well known science.Its probably oversprung.It wouldnt be much(in the scheme of diavels and ohlins) to get a new spring wound with a more sutable rate.I am sure Mr Taylor will have some ideas before a purchase of a Ohlins is actually required. The existing shock may be able to be revalved.
Eccentric chain adjuster need to be adjusted so both halves are turned at once so the adjustment can be made without affecting the height

[Crasherfromwayback]

Eccentric chain adjuster need to be adjusted so both halves are turned at once so the adjustment can be made without affecting the height

On an old GPZ1100 etc like my old one, it still changed things. But on the RS250, with the single sided swing arm, there is only the one cam. Adjusting the chain automatically changed the ride height.

[BMWST?]

On an old GPZ1100 etc like my old one, it still changed things. But on the RS250, with the single sided swing arm, there is only the one cam. Adjusting the chain automatically changed the ride height.
Yes i remember a kawasaki model iwas interested in(gpz 900?) and i thought that by rotating both the inner and outer eccentrics at the same time would move the wheel back but not raise the axle?

[Crasherfromwayback]

Yes i remember a kawasaki model iwas interested in(gpz 900?) and i thought that by rotating both the inner and outer eccentrics at the same time would move the wheel back but not raise the axle?

No. The axle went through both eccentric cams, on either side of the swing arm. Chain tension was adjusted, by rotating said cams, together, after backing off the pinch bolts on each swing arm *leg*. So to make that fat old bus turn a lil quicker, you'd rotate them 180 deg to lift the back end up. The same needs to be done with my old Slabbie. It's single shock (obviously), but the lower shock mount is also on an eccentric cam. Lift them up!

[Crasherfromwayback]

Sorry...forgot the pic...

330864

[Bass]

Of course preload compresses the spring - that's the entire point of it. By what mechanism do you propose preload raises and lowers the swing arm?



This is precisely what altering preload does. You compress the spring without changing the length of the shock - it therefore takes more weight to make the bike sag by the same amount. So for the same given weight, more preload means a higher ride height.

Bit late back into the fray and have to say sorry but this is all arse about face.

Thing is, it's so easy to prove it to yourself.
Go out to your bike with a tape measure and with the bike resting on its wheels (side stand OK but not centre stand) : -
1. measure the spring length
2. measure the distance from the back axle to some point on the frame
3. ensure that the shock has available movement in both directions i.e. that its not bottomed out or topped out.
4. increase the preload
5. take measurements 1 and 2 again with proviso 3.
You will find that the shock has extended, the ride height has increased but the spring is the same length as at the start. It must be because you haven't changed the load on it.
All you have done is push the top of the spring down relative to the frame, but the bottom is restrained only by the swing arm which is free to move away.

Of course, if you take it so far that the shock tops out, no more movement is available and so you will start to compress the spring, but that's out in ridiculous territory with sumo pillion passengers.

I have been trying to explain this for over a decade now, so I must be a truly hopeless tutor.

Maybe I should put a week's pay on it and retire on the winnings.

[cods4]

My understanding is that preload affects the sag and hence the stiffness of the spring because you are adjusting how much the spring is compressed when the shock is fully extended. I think it should usually not adjust the unloaded ride height, only the sag (and hence the loaded ride height). To make the shock the softest it can be, the preload should be adjusted right out so the spring is fully extended. This will however reduce the effective travel of the shock because more of it is now taken up by the bike/rider sag. On the other hand if you have the preload wound right in so the spring is more compressed and sag is reduced, then you may run the risk of spring bind which effectively reduces the travel of the shock. I'm not sure if this is possible with most motorcycle shocks or not.

Maybe there is some confusion between preload and ride height adjustment.

Ride height adjustment is not available on all bikes but you can see an example of how it is done here http://www.sportrider.com/suspension-setup-guide#page-7 . Ride height adjustment should not directly affect how the shock behaves but it will affect the geometry of the bike and hence how it behaves over bumps etc.

[cods4]

Bit late back into the fray but have to say sorry but this is all arse about face.

Thing is, it's so easy to prove it to yourself.
Go out to your bike with a tape measure and : -
1. measure the spring length
2. measure the distance from the back axle to some point on the frame
3. ensure that the shock has available movement in both directions i.e. that its not bottomed out or topped out.
4. increase the preload
5. take measurements 1 and 2 again with proviso 3.
You will find that the shock has extended, the ride height has increased but the spring is the same length as at the start. It must be because you haven't changed the load on it.
All you have done is push the top of the spring down relative to the frame, but the bottom is restrained only by the swing arm which is free to move away.

Of course, if you take it so far that the shock tops out, no more movement is available and so you will start to compress the spring, but that's out in ridiculous territory with sumo pillion passengers.

I have been trying to explain this for over a decade now, so I must be a truly hopeless tutor.

Maybe I should put a week's pay on it and retire on the winnings.


In this case aren't you talking about measuring the bike sag? Ride height would be the distance with the shock topped out? Maybe I have my terms mixed up.

[Bass]

I have a rear shock out of a 1998 CR250 here for a rebuild. If I wind the preload collars right off, I can compress the shock myself (a wee bit only) by just pushing down on it. If I was to wind the collars right up, I couldn't budge it no matter how hard I might try. So it's softer one way, and harder the other. So for people to say preload makes no diffence to how the shock/bike behaves, and is no softer or stiffer is simply not correct.

Mate, that's a limiting situation. You are taking your measurements with the shock fully extended and so the forces are being restrained by the internal mechanism.

Look, do what Ken Macintosh does.
Go and get your bathroom scales and put them on your drill press table.
Put one end of the shock on the scales and the other in the chuck mount. Use the drill press to force the shock off its end stop slightly.
Use the drill again to force the shock through a further increment (e.g. 1 cm) and use the scale to measure the force INCREASE required to achieve that increment.
Do it several times with several preload settings
Do it at several places in the stroke
You will find that the incremental force required is completely independent of the preload setting.
That is what Hooke's law is all about.

Of course it will make a difference to how the bike behaves but the stiffness remains the same as your measurements will have just proved.

P.S. If I'm wrong, I want to know about it immediately cos it means something new and so interesting. Also, I believe that some springs don't follow Hookes law well at the very start of their deflection.

[Bass]

In this case aren't you talking about measuring the bike sag? Ride height would be the distance with the shock topped out? Maybe I have my terms mixed up.

They are pretty much the same measurement for all practical purposes, except sag increases as ride height decreases and vice versa. Any two points which allow you to measure one, will also allow you to measure the other

[Bass]

My understanding is that preload affects the sag and hence the stiffness of the spring because you are adjusting how much the spring is compressed when the shock is fully extended. I think it should usually not adjust the unloaded ride height, only the sag (and hence the loaded ride height). To make the shock the softest it can be, the preload should be adjusted right out so the spring is fully extended. This will however reduce the effective travel of the shock because more of it is now taken up by the bike/rider sag. On the other hand if you have the preload wound right in so the spring is more compressed and sag is reduced, then you may run the risk of spring bind which effectively reduces the travel of the shock. I'm not sure if this is possible with most motorcycle shocks or not.

.

The first thing to realise is that you don't want the shock either topping out or bottoming out when you are riding. Your suspension just goes away if you allow that to happen. Anywhere in between those 2 points, the only way to change the equilibrium length of the spring is to add weight or remove weight.
To change the length of the spring you have to change the force on it and so if the shock is not at an end stop, the spring will be the length it needs to be to carry the load on it.
If you don't change the load, you don't change the spring length.

The only way that you can change the spring stiffness is to fit another one

As for ride height, yes, changing the length of the shock shaft is the true and pure adjustment that alters no other geometries. However, extending or retracting the shock shaft equilibrium position (as preload alterations do), has the same effect albeit with penalties to available shock movement.

[eldog]

Bass, maybe pictures would help or a web page address.

Sometimes diagrams help.

Some geometries are not that straight forward.

[Bass]

Bass, maybe pictures would help or a web page address.

Sometimes diagrams help.

Some geometries are not that straight forward.

The tricky part is to know how far to go into the discussion. I think that my knowledge is better than average but it still has gaping holes in it.
I once sat down and tried to describe the whole thing mathematically and the theory is actually not too bad if you are comfortable with a bit of calculus. The problem to getting a good picture was getting a measurement of the effect of shock seal friction and stuff like that.
Getting a gut feel for the whole picture is hard because it's all about change and rates of change.

Anyway, as for diagrams etc, the very best diagram I have for the effect of preload is my bike. It's all electrically adjustable and so I can demonstrate everything I have been saying to anyone interested in a few seconds and in glorious living colour. Just press the button and watch it all happen.

[jamjam]

I had a GPZ 900 22 years ago... fk i'm getting old :drool:

Anyway the original post does relate to comfort yes, it's ok on the motorway and street dragging like it's originally designed for i guess... my cock up on that one. It's not ok on our NZ back roads. I contacted Robert Taylor and he's getting an Ohlins in for me so i'm looking forward to getting that fitted in a few weeks and he reckons it will be way better for our roads. So on the balance of things I think that is the best way to go to get the best outcome.

I have been reading the posts you guys making about preload etc... I'm no expert (i do have some chicken strip left and did do daily power wheelies on my Monster but not clutch wheelies so i'm average, not expert) but my input is... Yes it raises the rear height, any bike I have changed this on (including dirt bikes) absolutely raises the height. I wouldn't say it makes it firmer necessarily but it makes the suspension work in a different part so the net effect is usually a "slightly" firmer feel through most of the preload adjustment... with the exception of the bottom (say 10%) of the adjustment makes the bikes feel soft and wallowy.

Of course the geometry changes with more preload, lift up the rear and the front tips in much quicker and the bikes become less planted... drop the rear too much and the front rides high or wide into the corner and mid corner along with a whole lot of other variables. So with raising the rear up high then yes you should also raise the front preload to get the right geometry and turn in.

As for the real details about how it all works... i'll stick to my day job that i'm better at.

[SVboy]

This is precisely what altering preload does. You compress the spring without changing the length of the shock - it therefore takes more weight to make the bike sag by the same amount. So for the same given weight, more preload means a higher ride height.[/QUOTE]

This is a concept on one of the effects of altering preload I can understand. Well put that man!

[eldog]

The tricky part is to know how far to go into the discussion. I think that my knowledge is better than average but it still has gaping holes in it.
I once sat down and tried to describe the whole thing mathematically and the theory is actually not too bad if you are comfortable with a bit of calculus. The problem to getting a good picture was getting a measurement of the effect of shock seal friction and stuff like that.
Getting a gut feel for the whole picture is hard because it's all about change and rates of change.

Anyway, as for diagrams etc, the very best diagram I have for the effect of preload is my bike. It's all electrically adjustable and so I can demonstrate everything I have been saying to anyone interested in a few seconds and in glorious living colour. Just press the button and watch it all happen.
If i have time. I will have a demo.

[F5 Dave]

Oh good grief! Anyway its a myth that you need to somehow ride a bike hard as to gain advantage from decent suspension. Bikes are built down to cost and sometimes crazy setup. As an example RT has stated that Ohlins valving spec for various Ducatis is well different from how they are made on Ducatis supplied with Ohlins std.

Maybe they want you to have your teeth rattled out on the test ride to make you think its a sports bike like no other.

Spend the money and enjoy.

I'm not going to enter the preload debate other than to say;
Draw an x/y graph.
Draw a diagonal line from zero
Draw the same line but a bit further up the x axis.

Congratulations you've just added preload without changing the spring rate.


But preloading is a bad idea. You still end up buying the same amount of drinks when you are out, just get far messier.

[Crasherfromwayback]

Mate, that's a limiting situation. You are taking your measurements with the shock fully extended and so the forces are being restrained by the internal mechanism.

.

Mate, I hear ya. But how will that shock behave, from the very top of it's travel right through to the bottom, if I take the spring off it completely? The very same feel all the way through the stroke right? How will it behave if I wind that much preload on it, that it coil binds?

[Bass]

Mate, I hear ya. But how will that shock behave, from the very top of it's travel right through to the bottom, if I take the spring off it completely? The very same feel all the way through the stroke right? How will it behave if I wind that much preload on it, that it coil binds?

Good points and everything I have said assumes the shock is good throughout its' stroke and that its not operating against any physical stops.

As a bit of an aside, but still on topic since the OP's comments were about a harsh ride, has anyone out there had a go at taking some specs to a spring manufacturer and getting a spring made? If so what problems arose?

I'm far from being a professional in the field but have picked up a couple of rules of thumb that worked OK for me on sport/tourers and adventure bikes. As I indicated a couple of posts ago, you can measure the spring rate with a drill press and a set of scales. However, I struggle to tell from riding the bike whether I stuffed up the damping settings or whether the wrong spring is in there. Can anyone point me straight?
This is one of the major holes in my experience. So I tend to use the difference between static sag and rider sag (in % of total stroke terms) as a first order indicator. Often, I've considered changing the spring but they're not always available and so I've wondered about getting one made.

I've also noticed that a new spring relaxes a bit during the first few days of its working life and so I guess I'd have to allow for that when specifying the length?

[pritch]

I've met so many riders who obsess with suspension tuning yet ride like a big blouse, (snip) Never pushed their suspension anywhere near it's limitations.


It me.

The improvement in comfort is worth it. Ducati are commonly too harsh for our roads and the stock hardware offers insufficient adjustment. The Ohlins equipped Ducati models are set up for the track and are very harsh. To get any level of comfort they need rebuliding to a more suitable spec.

An Ohlins improved the Hornet amazingly. My Ducati came with a spring to suit a midget, the Ohlins as supplied was far too harsh at Ducati specs, softened it was brilliant. The Triumph is a much nicer ride with the Ohlins fitted.

It's about more than the just the inherent sport riding limitations.

[F5 Dave]

My STR came with uprated fully adjustable suspension over the std model. You could adjust it from Dreadful to Fully Dreadful.
A spring and considerable revalve made it less like being kicked in the arse over expansion joints and skipping over corner stutter bumps to quite useful.
And any Nancy would have appreciated the difference.j I was lucky the shock was a fairly decent unit that was worth revalving. My Tiger shock was rubbish. The Ohlins replacement was streets ahead.

[SVboy]

My STR came with uprated fully adjustable suspension over the std model. You could adjust it from Dreadful to Fully Dreadful.
A spring and considerable revalve made it less like being kicked in the arse over expansion joints and skipping over corner stutter bumps to quite useful.
And any Nancy would have appreciated the difference.j I was lucky the shock was a fairly decent unit that was worth revalving. My Tiger shock was rubbish. The Ohlins replacement was streets ahead.

I have ridden a few STRs. Great bikes, but as you say, what a shitty rear shock.

[F5 Dave]

The shock is a reasonable quality kyb. But had a crazy 12kg spring and way too much rebound. Might have been OK 2 up, never tried.

Clickers are only fine tuning and past a certain range become innefective at higher speeds or destroy lower speed. And can delay opening of the compression stack at the start of the curve creating a sharp spike.

[BMWST?]

Good points and everything I have said assumes the shock is good throughout its' stroke and that its not operating against any physical stops.

As a bit of an aside, but still on topic since the OP's comments were about a harsh ride, has anyone out there had a go at taking some specs to a spring manufacturer and getting a spring made? If so what problems arose?

I'm far from being a professional in the field but have picked up a couple of rules of thumb that worked OK for me on sport/tourers and adventure bikes. As I indicated a couple of posts ago, you can measure the spring rate with a drill press and a set of scales. However, I struggle to tell from riding the bike whether I stuffed up the damping settings or whether the wrong spring is in there. Can anyone point me straight?
This is one of the major holes in my experience. So I tend to use the difference between static sag and rider sag (in % of total stroke terms) as a first order indicator. Often, I've considered changing the spring but they're not always available and so I've wondered about getting one made.

I've also noticed that a new spring relaxes a bit during the first few days of its working life and so I guess I'd have to allow for that when specifying the length?
take your spring to a spring manufacturer. He can tell you the specs just by measuring things. He can make a new spring based on the spring yougive him. You have to know what you want tho softer or harder.I went through this exercise when i was into mtn bikes.Ihadaquiredafewspringssoi went to see them and they measured them and told me the rates of the springs

[Bass]

take your spring to a spring manufacturer. He can tell you the specs just by measuring things. He can make a new spring based on the spring you give him. You have to know what you want tho softer or harder. I went through this exercise when i was into mtn bikes. I had acquired a few springs so i went to see them and they measured them and told me the rates of the springs

So it's feasible then - thanks for that.
I had read somewhere that even the major manufacturers struggle to make springs to a specific spring rate (though they can make to a pretty narrow range) and tend to sort them by rate after manufacture.
Always seemed a bit strange to me so don't know how correct it is.

[BMWST?]

So it's feasible then - thanks for that.
I had read somewhere that even the major manufacturers struggle to make springs to a specific spring rate (though they can make to a pretty narrow range) and tend to sort them by rate after manufacture.
Always seemed a bit strange to me so don't know how correct it is.
the only thing that i can say is that although the science of springs is well known the quality and consistency of the actual spring steel wire can vary. We buy steel plate in various thicknesses and make a kind of beam with it.In one area of steel the fastener penetrate the steel easily but in another area it is harder.I guess there are also variations that occur in the actual manufacturing process which introduces a variation between theoretically identical springs.

[Ocean1]

the only thing that i can say is that although the science of springs is well known the quality and consistency of the actual spring steel wire can vary. We buy steel plate in various thicknesses and make a kind of beam with it.In one area of steel the fastener penetrate the steel easily but in another area it is harder.I guess there are also variations that occur in the actual manufacturing process which introduces a variation between theoretically identical springs.

Also, the temperature and soak time in tempering is really really critical, so while it's not too difficult to make a production run of springs from material supplied in bulk that are pretty similar it's a bit trickier to make one or two to a high degree of accuracy. There's a little bit of art involved with the science.

You also need to be picky about the end finish spec. It matters.

[Bass]

I had figured that raw material variations could be a problem, especially for a small manufacturer at the bottom of the world. My eldest son currently drives a big rolling mill and from what he tells me, I can see how variations could arise from area to area within the work piece.
I had guessed that the tempering process could have a big effect but figured that it could be controlled pretty well with the gear that's out there these days.
Didn't know about the surface finish thing but. Any idea why it's so important?

Another aside - I was recently wandering around the workshop of a guy who has been a classic racer for about 40 years. He's building up a replica of the Norton that won the first IOM TT at the moment. He was measuring valve spring rates with his drill press and his wife's kitchen scales. He knows the closing force that he wants and so he then makes his valves the correct length for a particular spring. Apparently it's easier to make a valve to suit the spring rather than the other way around.

[Ocean1]

I had figured that raw material variations could be a problem, especially for a small manufacturer at the bottom of the world. My eldest son currently drives a big rolling mill and from what he tells me, I can see how variations could arise from area to area within the work piece.
I had guessed that the tempering process could have a big effect but figured that it could be controlled pretty well with the gear that's out there these days.
Didn't know about the surface finish thing but. Any idea why it's so important?

Another aside - I was recently wandering around the workshop of a guy who has been a classic racer for about 40 years. He's building up a replica of the Norton that won the first IOM TT at the moment. He was measuring valve spring rates with his drill press and his wife's kitchen scales. He knows the closing force that he wants and so he then makes his valves the correct length for a particular spring. Apparently it's easier to make a valve to suit the spring rather than the other way around.

Cooking temps and times are easy enough to control fairly accurately, it's slight variations in the composition of the alloy that cause problems in accurately predicting the outcome. Surface finish does have an effect, a surprisingly large one, because the surface is furtherest from the neutral axis in what is essentially an axial twist perpendicularly through the wire section. But by end finish spec I actually meant the way the last turn is shaped and the ends ground flat. It's reasonably critical in how symmetrical the spring behaves about it's centerline.

And yes, that's exactly how I measure springs, :laugh: You can also compare springs very accurately minus the scales by simply squashing the two together and measuring their respective changes in length.

[F5 Dave]

With sometimes surprising results. My last comparison of clutch Springs had the clearly stiffer design turn out identical to the std ones.
I use a press and scales for rear shock Springs and compress 20mm. (10 isn't enough)
But act with care. They store a fair bit of energy and can get very angry. Never been game to measure fork Springs.

[Bass]

But by end finish spec I actually meant the way the last turn is shaped and the ends ground flat.



Thanks,
I actually wondered for a moment whether you were talking about how the ends were made but decided wrong.

[Bass]

With sometimes surprising results. My last comparison of clutch Springs had the clearly stiffer design turn out identical to the std ones.
I use a press and scales for rear shock Springs and compress 20mm. (10 isn't enough)
But act with care. They store a fair bit of energy and can get very angry. Never been game to measure fork Springs.

Sage advice.
Why is 10 not enough? Insufficient change?

[Ocean1]

With sometimes surprising results. My last comparison of clutch Springs had the clearly stiffer design turn out identical to the std ones.
I use a press and scales for rear shock Springs and compress 20mm. (10 isn't enough)
But act with care. They store a fair bit of energy and can get very angry. Never been game to measure fork Springs.

Aye, non-amateurs get robust cages involved.


Sage advice.
Why is 10 not enough? Insufficient change?

In theory it's a perfectly linear progression, (and the only valid reason I can think of that it might not be is those end turns I mentioned coil binding and effectively shortening the overall material under torsion), but in practice it ain't perfectly so.

Also, no matter how good your measuring equipment is, measuring more of something is betterer than otherwise. So is staying away from the ends of the range of variables measured, so squish it a bit before hitting zero, take a few measurements over as much of the stroke as possible, and do it enough times that your numbers are repeatable.

Having said all that I don't believe I'd notice any spring rate change less than 3-4%. Probably more on a road bike.

[nzspokes]

Interesting discussion on bikes on KB? Has the world gone mad?

[Bass]

Also, no matter how good your measuring equipment is, measuring more of something is betterer than otherwise. So is staying away from the ends of the range of variables measured, so squish it a bit before hitting zero, take a few measurements over as much of the stroke as possible, and do it enough times that your numbers are repeatable.

Having said all that I don't believe I'd notice any spring rate change less than 3-4%. Probably more on a road bike.

All good practice and designed to eliminate systematic error and minimise relative error, but the reason I asked was in Dave's other comments. The more you squish, the more energy you store and the more potential damage if the bitch gets loose. Modern suspender setups require grunty springs and so some safety considerations methinks as per your cage comment

[F5 Dave]

I found it hard to be consistent with just 10mm. 20mm /20 was beterer and well acurate enough to tell the difference between 8kg/mm and 8.8. Scales would go out of range with more. Heck maybe i used 15, be written in my book somewhere. Proper rigs have adjustable stops and vernier calipers bolted to them.

[cods4]

The guy who built the suspension for my rally car has a suspension dyno and gave me a printout of the shock behaviour at all the rebound settings. Not sure if this is sometimes done for motorbike suspension?

[AllanB]

The guy who built the suspension for my rally car has a suspension dyno and gave me a printout of the shock behaviour at all the rebound settings. Not sure if this is sometimes done for motorbike suspension?

I'm sure Mr Taylor has something like this.

[Bass]

I'm sure Mr Taylor has something like this.

Very likely but that takes all the challenge and some of the fun out of it.

[Ocean1]

I'm sure Mr Taylor has something like this.

He does, but they'e used for measuring damping performance, not spring rates.

In fact I'm pretty sure the last time I was there he took the spring off a shock before testing it, which makes perfect sense.

[BMWST?]

to some of us the behaviour of the shock can not always be totally seperated from the behaviour of the spring.To have the actual shock behaviour optimised seperate from the spring rate would be a very important step in the modification to the suspensension.I am sure that the valving of the shock is very closely aligned with the actual spring rate

[nzspokes]

I'm sure Mr Taylor has something like this.

Which is why next week Im sending him the shock and forks from the CBR.

[DMNTD]

Owned one, loved it and once I changed the set up it was most epic mid corner, sweepers and straights.
To be fair they are obviously different to set up pre cornering but once you get the knack you can own most sportsbike riders

[jamjam]

Once you understand the characteristics of a bike you can really push them and surprise people how quick you can corner something that isn't a sports bike. It is a heavy slug in comparison I won't deny but you can still make it do what you want it to. it can certainly carve through corners if you are prepared to lean it more and set up a good line.

The big problem here is the bike is set up for smooth roads end of story and has little room to move on settings. I reckon the shock internals are as much to blame as the spring. I'm looking forward to getting RT to fit the Ohlins rear and also he's gonna do the Andreani internal cartridge kit for the forks. I figure sort the front and rear in one hit and be done with it :bleh:

After that I'm confident this bike will be sweet to ride on our nz bumpy roads :niceone:

[F5 Dave]

Best time to do upgrades is early in your ownership, that way you enjoy them for longer.

Had a bit of a chuckle before. 7 pages of `My Ducati has hard suspension `. . . well yeah.

Next week we'll cover `My Hardly is a bit loud`

[pritch]

Clickers are only fine tuning and past a certain range become innefective at higher speeds or destroy lower speed.

Was just looking back over the thread; from memory the Ohlins manual says that you should be within five clicks of their recommended setting. If you need more than that you should be looking at spring or valving changes.

[MD]

In saying that it is ironic that for the first time in decades I'm changing my current bikes shock for a better one. But that is after 3 months of serious hard riding to get to know it and too many scary moments that have convinced me I'm playing Russian roulette.

If you ride heaps and it does sound like you have tried all possible variations with the OEM then yeah, change bikes or change the suspenders.

Apologies if it sounds like I did some preloading before writing this.

Not being a fan of changing OEM suspension I must confess today I had my first chance to go for a decent blat with the new Nitron shock on the MT09. Bloody hell it was a vast improvement. Most noticeable was when riding in the wet the bike gives so much more confident feedback. Pushed it harder than before in the wet. Handling in the dry was way better. Well spent money at KSS.

[biggo]

Not being a fan of changing OEM suspension I must confess today I had my first chance to go for a decent blat with the new Nitron shock on the MT09. Bloody hell it was a vast improvement. Most noticeable was when riding in the wet the bike gives so much more confident feedback. Pushed it harder than before in the wet. Handling in the dry was way better. Well spent money at KSS.

Hi

Did you get Robert to do any changes to your front suspension or just the nitron on the rear? Have a Tracer and a KSS make over is on the list to do :)

[MD]

Hi

Did you get Robert to do any changes to your front suspension or just the nitron on the rear? Have a Tracer and a KSS make over is on the list to do :)

No they shipped the shock to me set up based on my weight and height and riding preference. Bloody awesome.
We agreed to disagree that the front on the MT09 (2017 versions onwards) needs attention. I prefer to enter corners hard and carry plenty of lean, rather than the more common approach of; brake hard -turn-accelerate out. I have to rely on the front working and for me the MT09 does the job well as is with OEM.

[jamjam]

I too have never been a modifier but this time round something needs to be done... the parts have arrived at KSS and it's booked in for the work to be done next week. Ohlins shock and Andreani cartridge for the forks. I'll take it for a good spin afterwards and report back. Right now it's very firm and bucks over high speed bumps, the front and rear don't feel like they are responding at the same rate, the rear pushes the front mid corner and the bike skittles over imperfections on corners. I don't have confidence to push it hard through a corner so have been taking it easy. Hopefully all that changes next week.

On the plus side it does do wheelies (which I thought it wouldn't) and/or lights up the back depending on road surface grip :wings:

I think I am going to really like this bike :woohoo:

[jamjam]

Update since suspension work.

First of all I highly recommend that if you need to do anything suspension on your bike then just take it straight to Robert Taylor of KSS in New Plymouth. He knows his stuff and will do absolutely everything to make sure you are happy with your bike. His customer service is outstanding and his work is meticulous.

He installed an Ohlins shock and Andreani cartridge fork kit and to cut to the chase after several test runs, explaining the symptoms, tweaks and some further changes to the shock internals and valves and trying a different spring weight (then going back again once we had the geometry right) we got it perfect.

The bike just glides over bumps (yes you still feel some bumps that you would on any bike) but they are mostly smoothed out and not harsh anymore. The turn in is quick and precise, holds the line well without that feeling that the tire is being over worked and conforms to the road nicely. It feels and turns very much like a street bike now - like my old Monster did.

So yes I am really happy with the way the bike rides now... My riding weight is 83kg so anyone out there with a Diavel finding it too harsh then go see KSS and they will sort it out for you :niceone: