Suspension dyno

[Robert Taylor]

Following on from my assertions on another thread the attachment talks about ''cross talking'' that occurs with BPF forks ( or cynically ''Bad Performing Forks'' )

The reality is that because we have a sophisticated suspension dyno we are actually able to graphically view this issue and therefore are able to then make compensatory adjustments that will confirm that we have exactly hit target. To try and do this manually would take ''a month of Sundays'' . And even then the end result may still be a little wide of the mark

What we have also been able to achieve is revalving of many standard pistons ( of suitable port size and configuration ) without recourse to fitting an aftermarket piston set and the all too often ''setting banks'' that are less than ideal. In using the dyno we end up with a much better result at most often a lower overall cost. So before you jump in and purchase an aftermarket piston kit this is a serious and most often superior option. Indeed even with aftermarket pistons dyno tuning delivers the best end result, much as with power commanders and other performance components for engines.

Those who are prepared to understand suspension dyno graphs will see how the suspension responds to adjustment and will be able to make very effective use of such adjustments on road or track

[Mental Trousers]

I'm not surprised that there's cross talk because there's nothing to stop fluid flowing back through the bypass circuit. What is surprising is there's cross talk from rebound to compression but not the other way.

[AllanB]

Cross-talking is what happens after your wife finds the new suspension courier package sitting on the back step :niceone:


So BPF will die away and be replaced with some other acronym that probably refers to the previous set-up?

[tippersv]

Cross-talking is what happens after your wife finds the new suspension courier package sitting on the back step
:killingme:killingme

[Robert Taylor]

I'm not surprised that there's cross talk because there's nothing to stop fluid flowing back through the bypass circuit. What is surprising is there's cross talk from rebound to compression but not the other way.

With the rebound circuit it is a bleed passage through the shaft that flows in both directions. But on the compression side the external adjuster doesnt alter a compression bypass bleed because there isnt a seperate bleed circuit. It alters preload on a cup that is against the shim stack. Hence that is why compression adjustments will not affect rebound.

My point is it neccessitates having a suspension dyno to actually view this and understand it fully. Having such equipment is really what sets us apart from the rest of the industry players and our level of understanding is lifted immensely by graphically viewing the end result. Plus much as with engine dyno's it has dispelled a few myths.

Back around 2003 with our first suspension dyno ( it was Italian with ''Italian reliability'' ) we did a lot of dyno development work with the Ohlins rear suspension fitted into Shaun Harris's title winning CBR600RR. The success he had can ( in part ) be directly attributed to the gains we made in suspension valving and setup from the time we spent on the dyno. The same basic techniques were also applied later into Craig Shirriffs title winning GSXR600 in 04 ( I think ) . The current Roehrig dyno makes the old Italian dyno look like it was out of the 18th century. Work we have done with the current dyno assisted no end in attaining the first 4 places in the NZ 2013/14 Superbike championship. Having a suspension dyno doesnt of course make you an instant expert but long term it lifts your level of understanding, immensely.

The reality is that its use to verify that we have spec'd the internals to fit the application ( compliant road use through to hardcore track use ) is of priceless value. To those that might decry such equipment pedigree suspension manufacturers employ and use suspension dynos all the time. Its also a totally disingenuous thing to offer that ''setting banks'' from the manufacturers are totally foolproof and will allow for every scenario. Or that ''the suspension we sell is perfect out of the box''. That of course is total bollocks and has proven to be so.

While our demographic disposition may look like a burden to some ( New Plymouth ) the reality is we have the most complete and well equipped suspension workshop in New Zealand, by a huge margin. Because we have invested totally to offer such a COMPLETE service.

[AllanB]

BPF. Also makes me wonder about the new fancy electronic units appearing. Are they the future? Variables on a specific bike with potentially different riders over significantly different surfaces - can the electronics cater for all? And if they are the future why are they not appearing on race tracks - one could conceivably program the computer/suspension to suit each corner!

I presume the dyno would not be applicable to electronic suspension? Technology aye ..............? I swear we over complicate a lot of shit.

[Gremlin]

BPF. Also makes me wonder about the new fancy electronic units appearing. Are they the future? Variables on a specific bike with potentially different riders over significantly different surfaces - can the electronics cater for all? And if they are the future why are they not appearing on race tracks - one could conceivably program the computer/suspension to suit each corner!
If different riders have different preferences then no, one electronic setup isn't going to suit everyone. Also, one moment the bike can feel soft, then the next it's firm. Some riders want the suspension ball park and they're ready to ride (myself included). Others won't be happy until it's fully setup to suit them to a T (my boss is one).

Electronic suspension is still a shock, just with some extra variables. I was in Robert's workshop Monday, having the Mechatronic gear serviced, and we swapped the rear spring for a spring rate one higher. Now time in the seat is required to find out whether it's fixed a couple of things, but has no drawbacks...

[Robert Taylor]

BPF. Also makes me wonder about the new fancy electronic units appearing. Are they the future? Variables on a specific bike with potentially different riders over significantly different surfaces - can the electronics cater for all? And if they are the future why are they not appearing on race tracks - one could conceivably program the computer/suspension to suit each corner!

I presume the dyno would not be applicable to electronic suspension? Technology aye ..............? I swear we over complicate a lot of shit.

Slowly they will be the future yes. As the market accepts it, as volume can bring the price to manageable levels. Manufacturers dip their toe in the water with a very small number of targeted models to see how the market will react rather than going in boots and all. You have to remember that investment is massive and you must also see a return, with profit. Profit funds further R&D.

What people also often fail to realise is that manufacturers ( those that lead rather than those that follow or brazenly copy ) only have so much R&D capacity and so many staff resources. R&D takes lots of time and lots of money and that is also reflected in the price of the product. Ohlins ( for example ) have been working on electronically assisted suspension since 1984.

Our dyno is totally applicable to Ohlins electronic suspension yes, because we also invested in the Ohlins specific diagnostic equipment and interface tools. And a trip to Sweden to learn more. That is a further distinction we have over other industry players in NZ.

Ohlins Mechatronics appeared briefly in WSBK and won races comprehensively before being banned by the cavemen that so often make the rules. WP also had a system in the pipeline.

The potential is huge and personally I totally embrace that.

[husaberg]

Slowly they will be the future yes. As the market accepts it, as volume can bring the price to manageable levels. Manufacturers dip their toe in the water with a very small number of targeted models to see how the market will react rather than going in boots and all. You have to remember that investment is massive and you must also see a return, with profit. Profit funds further R&D.

What people also often fail to realise is that manufacturers ( those that lead rather than those that follow or brazenly copy ) only have so much R&D capacity and so many staff resources. R&D takes lots of time and lots of money and that is also reflected in the price of the product. Ohlins ( for example ) have been working on electronically assisted suspension since 1984.

Our dyno is totally applicable to Ohlins electronic suspension yes, because we also invested in the Ohlins specific diagnostic equipment and interface tools. And a trip to Sweden to learn more. That is a further distinction we have over other industry players in NZ.

Ohlins Mechatronics appeared briefly in WSBK and won races comprehensively before being banned by the cavemen that so often make the rules. WP also had a system in the pipeline.

The potential is huge and personally I totally embrace that.

Honda and whitepower raced with electronic set ups in the mid 90's, Doohan and Beigie wanted nothing to do with it.
The NSR500 with no mods or setup went 1 or maybe it was two seconds faster at the first attempt with out of the box Ohlins front and rear. Compared to the works Showa set up. With Doohan onboard.
oh I feel a 10% discount coming my way lol.
I have a pic of the electronic shock somewhere, I think the WP setup as well

[caseye]

Serious question Robert.
I'm happy to ride the NP and let you guys do the bizzo on my 09 Bandit, what sort of dollars am I looking at to make it suit me? without changing anything that doesn't absolutely ( You suggest it) need changing.
I know, variables mean it's hard, but a ball park figure.
Further if i could arrange for 2-4 riders to come down is a Saturday morning/day sufficient?

[Robert Taylor]

Serious question Robert.
I'm happy to ride the NP and let you guys do the bizzo on my 09 Bandit, what sort of dollars am I looking at to make it suit me? without changing anything that doesn't absolutely ( You suggest it) need changing.
I know, variables mean it's hard, but a ball park figure.
Further if i could arrange for 2-4 riders to come down is a Saturday morning/day sufficient?

If perhaps you can provide your e-mail address I will answer by those means, thanks

[Gremlin]

Further if i could arrange for 2-4 riders to come down is a Saturday morning/day sufficient?
I think he likes his weekends if possible, plus travels for racing events around the country. Weekdays suit better I think.

In terms of the suspension, I can qualify re time. It depends on your bike. If you want to pay less, then give him the shock for the work, don't make him remove it and install it (but he can if you want). Some shocks come out with very little work, others take shitloads of time.

First time, remove BMW suspension and install Ohlins, around 10 hours (rode it down so had to remove and install everything required). 2nd time, transported it down with excess panels removed already and left the bare minimum on to make it ridable for testing. Took about 7 hours all up, but I was twiddling my fingers while I gave them the shocks for servicing (one at a time).

[Robert Taylor]

Honda and whitepower raced with electronic set ups in the mid 90's, Doohan and Beigie wanted nothing to do with it.
The NSR500 with no mods or setup went 1 or maybe it was two seconds faster at the first attempt with out of the box Ohlins front and rear. Compared to the works Showa set up. With Doohan onboard.
oh I feel a 10% discount coming my way lol.
I have a pic of the electronic shock somewhere, I think the WP setup as well

Of course, development is relentless and the potential huge

[Drew]

The article didn't seem to say what bike the forks came from. At the end, it says the standard piston is shit (due to too small port area) and to replace it with Racetech items. You say in your opening statement that it's often cheaper and better to stick with original pistons, without going into specific models with too small a port area.

To sum up, I have learned nothing from the article. I did however learn why rebound clicker adjustment effects compression, though I knew already that it happened. That was from a reply to a specific question, directed at the good Doctor though.

Still summed up, I learned nothing from the article. Robert, I'm billing you for the ten minutes all of this has taken!

[nzspokes]

Out of interest Robert, would I get crosstalk in my VTR1k forks? I know they are old in design. Im very happy with them after the Gold Valves went in.

Interesting read. :niceone:

We have electronic bicycle shocks that are terrain sensitive. :cool:

[Drew]

Out of interest Robert, would I get crosstalk in my VTR1k forks? I know they are old in design. Im very happy with them after the Gold Valves went in.

Interesting read. :niceone:

We have electronic bicycle shocks that are terrain sensitive. :cool::facepalm:

Yip. It's why manufacturers will often only put rebound adjusters on forks and shocks I reckon.

Robert, how say you savage?

[nzspokes]

And I must say its nice to see a thread on KB about a tech topic.

[Mental Trousers]

Further if i could arrange for 2-4 riders to come down is a Saturday morning/day sufficient?

Robert will answer, but here's what I do.

I turn up at their workshop as early as possible, pull the forks out, hand them over to Denis, pull the shock out, hand it over Robert. Then I try and stay out of the way (not always successful though) while they do their stuff. Once they're finished I put the forks and shock back in the bike. When it's all back together they do a measure, set preload and rebound on both ends, after which I load up and disappear.

This saves me up to 5 hours of labour on the CBR (not the nicest in the world to get the rear shock out but not the worst either), without which labour alone would be about 7-8 hours.

So pulling the suspension yourself in their workshop means you save a whole bunch of money but they also do the initial setup on the bike. Once that's done you ride it and tweak the clickers until it's as close to spot on as possible.

[caseye]

Robert will answer, but here's what I do.

I turn up at their workshop as early as possible, pull the forks out, hand them over to Denis, pull the shock out, hand it over Robert. Then I try and stay out of the way (not always successful though) while they do their stuff. Once they're finished I put the forks and shock back in the bike. When it's all back together they do a measure, set preload and rebound on both ends, after which I load up and disappear.

This saves me up to 5 hours of labour on the CBR (not the nicest in the world to get the rear shock out but not the worst either), without which labour alone would be about 7-8 hours.

So pulling the suspension yourself in their workshop means you save a whole bunch of money but they also do the initial setup on the bike. Once that's done you ride it and tweak the clickers until it's as close to spot on as possible.

Cheers mate, sounds like a plan!

[Robert Taylor]

The article didn't seem to say what bike the forks came from. At the end, it says the standard piston is shit (due to too small port area) and to replace it with Racetech items. You say in your opening statement that it's often cheaper and better to stick with original pistons, without going into specific models with too small a port area.

To sum up, I have learned nothing from the article. I did however learn why rebound clicker adjustment effects compression, though I knew already that it happened. That was from a reply to a specific question, directed at the good Doctor though.

Still summed up, I learned nothing from the article. Robert, I'm billing you for the ten minutes all of this has taken!

In your case you are a lost cause and the article wasnt targeted at you. In parallell that idiot 16 year old schoolboy that refuses to cut his hair to comply with school rules has also clearly learned nothing

[Robert Taylor]

Serious question Robert.
I'm happy to ride the NP and let you guys do the bizzo on my 09 Bandit, what sort of dollars am I looking at to make it suit me? without changing anything that doesn't absolutely ( You suggest it) need changing.
I know, variables mean it's hard, but a ball park figure.
Further if i could arrange for 2-4 riders to come down is a Saturday morning/day sufficient?

I will pm you an indicative cost independently. We dont open on Saturdays Im sorry as we are already away for so many part or full weekends in every year that we savour the very few that we get. Also it would mean convincing my 2IC Dennis to work on a Saturday ( at overtime rates that very much takes the edge off already slender margins) That he wouldnt be keen on. That on top of 12 hour weekdays would be lunacy. We can do on a Friday or a Monday ( for example ) and with 2 of us on deck could turn it round quickly

[Robert Taylor]

Out of interest Robert, would I get crosstalk in my VTR1k forks? I know they are old in design. Im very happy with them after the Gold Valves went in.

Interesting read. :niceone:

We have electronic bicycle shocks that are terrain sensitive. :cool:

A little yes , but much less than with BPF forks that for any given distance of movement push approximately ten times more fluid than your 20mm cartridges. The etiquette with any forks or shock is always to be in the habit of adjusting rebound first. That of course doesnt in reality matter with totally idependent systems that dont cross talk. But the other factor is that over slow rebound is a big contributor to a harsh ride, so you first eliminate that as a contributor before messing with compression clickers ( if fitted )

[Robert Taylor]

:facepalm:

Yip. It's why manufacturers will often only put rebound adjusters on forks and shocks I reckon.

Robert, how say you savage?

I shouldnt really respond as you already know and wont learn anything! ( You really are a prize cock at times! )

The first reason that only rebound adjusters may be fitted is COST, as is the second, as is the third and so on. Thats also why we are now burdened with BPF forks, they are cheaper to make

[Robert Taylor]

Robert will answer, but here's what I do.

I turn up at their workshop as early as possible, pull the forks out, hand them over to Denis, pull the shock out, hand it over Robert. Then I try and stay out of the way (not always successful though) while they do their stuff. Once they're finished I put the forks and shock back in the bike. When it's all back together they do a measure, set preload and rebound on both ends, after which I load up and disappear.

This saves me up to 5 hours of labour on the CBR (not the nicest in the world to get the rear shock out but not the worst either), without which labour alone would be about 7-8 hours.

So pulling the suspension yourself in their workshop means you save a whole bunch of money but they also do the initial setup on the bike. Once that's done you ride it and tweak the clickers until it's as close to spot on as possible.

Yes I can confirm that if the customer has the mechanical skill ( and sympathy ) to remove and refit his own suspension we will happily provide the tools etc thereby the clock wont be ticking for same. It suits the customer and his pocket and also suits us!

( Note that Gremlins example is an extreme one as he has the full blown electronic suspension with wiring looms etc )

[Drew]

I shouldnt really respond as you already know and wont learn anything! ( You really are a prize cock at times! )

The first reason that only rebound adjusters may be fitted is COST, as is the second, as is the third and so on. Thats also why we are now burdened with BPF forks, they are cheaper to make

I don't by any stretch, know much at all. That's why I used the format of a question.

[Robert Taylor]

Suffice to say that for those dealers in major centres that work with us they have the benefit of what we have and continue to learn and develop with our suspension dyno. Such dealers can either do some or all of the work or can facilitate / co-ordinate sending suspension units to us, then do the final setup. This will suit riders that dont have the time to be able to come to New Plymouth.

[Robert Taylor]

I don't by any stretch, know much at all. That's why I used the format of a question.

The article used the example of a GSXR600 BPF fork. But as these BPF systems are essentially generic through the 600s ( and a 750 ) in 37mm form and 39mm form for the bigger bore bikes they all have exactly the same characteristics, limitations and overall performance that is a little wanting. Especially in their inability to absorb abrupt bumps to a credible level.

[Kickaha]

I shouldnt really respond as you already know and wont learn anything! ( You really are a prize cock at times! )
That statement isn't accurate, he is a cock all the time

[Drew]

The outright lap record around Manfeild on a 600 is still held by Sketchy, running a stock Gixxer BPF front end.

Are they just poo on the road,

[nzspokes]

A little yes , but much less than with BPF forks that for any given distance of movement push approximately ten times more fluid than your 20mm cartridges. The etiquette with any forks or shock is always to be in the habit of adjusting rebound first. That of course doesnt in reality matter with totally idependent systems that dont cross talk. But the other factor is that over slow rebound is a big contributor to a harsh ride, so you first eliminate that as a contributor before messing with compression clickers ( if fitted )

So on my old bike its common to swap GSXR 750, CBR, RC51 forks on to them. Would I be right in saying that has limited improvement as the damper is not that much better? Obviously being upside down and bigger diameter its much stiffer. As we have spoken of before i am looking at a brace for the stock forks.

Would you consider the stock VTR forks to have a harsh rebound damper? Ive never ridden the fork stock as I fitted the gold valves to the compression side when I got the bike. Mine is a little harsh in the fork but again I believe that could be the seals as they are the All Balls ones.

On a side note would the BPF forks need more regular fluid changes?

[Gremlin]

( Note that Gremlins example is an extreme one as he has the full blown electronic suspension with wiring looms etc )
Simply pointing out what is possible, and that it's each bike to their own as to how long it could take. :laugh:

For example... On the BMW, the first step to removing the front shock is taking the back seat off... :facepalm:

[Robert Taylor]

The outright lap record around Manfeild on a 600 is still held by Sketchy, running a stock Gixxer BPF front end.

Are they just poo on the road,

With an Ohlins rear and steering damper and with some pre mods that we had done inside those BPF forks, yes. And yes on the road they are quite horrible on bumpy surfaces. When you fit the Race Tech high flow piston kits they are markedly better, excepting the setting bank recommendations for rebound are way off the mark. ( which makes a mockery of the self instal philosophy ) Thats where ( again ) the suspension dyno has been worth its weight in gold

[Robert Taylor]

So on my old bike its common to swap GSXR 750, CBR, RC51 forks on to them. Would I be right in saying that has limited improvement as the damper is not that much better? Obviously being upside down and bigger diameter its much stiffer. As we have spoken of before i am looking at a brace for the stock forks.

Would you consider the stock VTR forks to have a harsh rebound damper? Ive never ridden the fork stock as I fitted the gold valves to the compression side when I got the bike. Mine is a little harsh in the fork but again I believe that could be the seals as they are the All Balls ones.

On a side note would the BPF forks need more regular fluid changes?

If the alternative forks add a compression clicker where there was none with the original then they have more potential from that perspective alone. There are some many other variables so there cannot be a standard /regimented answer. Some have good pistons, some dont. Etc etc.

Rebound is normally not so bad on the VTRs but there is still scope for improvement. As we almost always change spring rate and preload that then dictates that we have a rebound force curve commensurate with same.

If you have too high an oil viscosity that can help to make the forks lazy and harsh, but again variables. Certainly though the seals you mention cause MASSIVE friction and therefore harshness. We refuse point blank to fit them .

There is no reason I can see that fork oil interval changes need to be different for BPF. The reality being that suspension oil is in most cases changed too infrequently anyway.

[Robert Taylor]

Simply pointing out what is possible, and that it's each bike to their own as to how long it could take. :laugh:

For example... On the BMW, the first step to removing the front shock is taking the back seat off... :facepalm:

Yes indeed, it was just that your example was quite extreme due to the complexity and most installations are very quick. Id hate everyone reading to think that your example was typical, which of course it very much isnt

Have you ridden with the firmer rate spring yet?

[nzspokes]

If the alternative forks add a compression clicker where there was none with the original then they have more potential from that perspective alone. There are some many other variables so there cannot be a standard /regimented answer. Some have good pistons, some dont. Etc etc.

Rebound is normally not so bad on the VTRs but there is still scope for improvement. As we almost always change spring rate and preload that then dictates that we have a rebound force curve commensurate with same.

If you have too high an oil viscosity that can help to make the forks lazy and harsh, but again variables. Certainly though the seals you mention cause MASSIVE friction and therefore harshness. We refuse point blank to fit them .

There is no reason I can see that fork oil interval changes need to be different for BPF. The reality being that suspension oil is in most cases changed too infrequently anyway.

I will pull the rebound rods and send them down to you next time they are out. It doesnt have a comp clicker but I have wondered if a F4i comp piston would fit.

Those seals will be coming out soon.

[Gremlin]

Have you ridden with the firmer rate spring yet?
No, got home around middle of Tuesday, pulled it apart again to remove the CB radio, got it back together end of Wednesday, and this weekend I'll put some km on...

[Robert Taylor]

I will pull the rebound rods and send them down to you next time they are out. It doesnt have a comp clicker but I have wondered if a F4i comp piston would fit.

Those seals will be coming out soon.

Try the seals first and foremost with no other changes.

The other factor ( but this is a minefield that I dont have the energy for at this time ) is the amount of bypass bleed that is added or taken away. It can be a very fine balance and often counter-intuitive

[nzspokes]

Try the seals first and foremost with no other changes.

The other factor ( but this is a minefield that I dont have the energy for at this time ) is the amount of bypass bleed that is added or taken away. It can be a very fine balance and often counter-intuitive

Interestingly ive just read a thread on this. An "expert" said they need a 1mm bleed drilled I think in the gold valve. This expert had some time racing these bikes and also did a change to the rebound stack.

I will try to do some reading on the bleed.

[Robert Taylor]

Interestingly ive just read a thread on this. An "expert" said they need a 1mm bleed drilled I think in the gold valve. This expert had some time racing these bikes and also did a change to the rebound stack.

I will try to do some reading on the bleed.

Yes bypass bleed can be a very critical thing. Too little and it can be harsh / non responsive . Too much bleed in the base pistons and you can reduce back pressure on the ''pumping'' piston. That shows as cavitation in the third quadrant of a ''full circle'' dyno graph as it reverses direction. The very earliest stages of cavitation can be picked up on a premium suspension dyno ( such as our Roehrig equipment ) that cant be picked up on a manual push test such as regular mechanic with no such equipment would do.

Most forks arent pressurised like a quality shock absorber so anyone engaged in modifying these has to be VERY attentive to what a fine line it is to achieve a credible level of ''pressure balance''. Frankly this is where I personally have serious reservations about the mentality of self instal. Its more of a marketing and sales exercise than doing what is technically correct, at all times.

Another major advantage that I think that we KSS effectively offer is the benefit of our accumulated experience. My 2IC Dennis Shaw is a guy that I have worked with / known most of my working life. His experience is decades and he comes up with clever solutions. Moreover when we are each working on various jobs we discuss constantly what we are doing and the old adage that ''two brains are better than one'' is ringing very true for us.