Suspension settings.. has anyone tried....

[cowpoos]

I'm having a bit of trouble understanding the terminology you guys are using.

As far as I know there is no such thing as a digressive linkage. I think what is meant is a digressive shock (or digressive damping) which uses a progressive shim stack to provide a high initial stiffness [the opposite is called a 'rising rate' shock which starts with a low initial stiffness]. The linkage is simply the bar that joins the bottom of the shock to the chassis the swingarm and chassis. The bit that connects to the chassis is called the link rod. Its purpose it to translate the virtical distance of wheel travel to a force applied to the end of the shock - usually using a reduction ratio.

A [pro-link] linkage uses tangenital forces (from what I can see) and is normally progressive or linear (very rare these days) - Since the other word for tangential is digressive perhaps the latter word was substituted by mistake.

The only other thing I can think of is that the linkage rod has been very badley designed and has an angle making a high resistance before it pivots enough to travel freely - I cant see that happening on the Honda unit pro-link. The high initial resistance would make it 'digressive' in behaviour [to use the damping term].

The RC211V uses a bog standard unit pro-link system, similar to the ones that are fitted to the cibby 600 and 1k (but obviously a higher spec). It's upper mount is on the swingarm rather than on the frame as on the old pro-link system. If they [honda] have reshimmed it to be digressive, no-one would know except the chap that builds the shock. But the design change is simply to make the shock go straight up and down, rather than also back and forth as well and to remove forces being applied to the chassis.

first digessive means basically starts off firm and gets softer as it progresses...for a road bike that at high speeds hit a small [or large] bump...you need to move the suspension quickly...but more importantly...when on large lean angles [or even medium ones] the suspension is compramised...as the suspension is trying to transfer a vertical force into a semi horizontal force...and there xtra fricton involved...there is more resistance invloved...making motorbike suspension work propally at high lean anglers[and medium one] invloves making the suspension digresive in nature...since you bike is cornering the suspension is loaded somewhat....probally around 40-65% of its travel is loaded on to it....so the softer nature of the suspension at those lean angles can be transfered alot easyier thru the suspension rather than making the bike wooble or tyres lose traction...its hard to see how this works in words...but I know you will think this through [judging by your posts you a real thinker]

think about what will happen to your bike at 45 degrees...if it hits a bump that will impact your bike in a vertical nature...where will the force's travel if the suspension is linear or progresive [progesive meaning harder as the suspesion moves through its travel]

[TwoSeven]

Are you talking front or rear suspension. Lean angle has not much affect on front other than stiction, and sidewall push for the tires.

But, what you are saying is that the bike weighs more as it goes round a corner so therefore needs more resistance. However, a progressive fork would also work - but, if there is a bump in the corner, there wouldnt be sufficient travel left to deal with it. So digressive would still allow for fork travel.

[cowpoos]

Are you talking front or rear suspension. Lean angle has not much affect on front other than stiction, and sidewall push for the tires.

But, what you are saying is that the bike weighs more as it goes round a corner so therefore needs more resistance. However, a progressive fork would also work - but, if there is a bump in the corner, there wouldnt be sufficient travel left to deal with it. So digressive would still allow for fork travel.

are you serious!!!!! your just trying to wind me up or something....?????

[TwoSeven]

no, I drew [or tried to] a vector diagram on what you are talking about. Somehow, you are implying that the bike increases its weight when it goes around a corner.

since you bike is cornering the suspension is loaded somewhat

Only way you can compress suspension is to increase the mass of the object on top, or put a bump underneath - you mentioned no bump. So must be increasing the weight of the bike.

Sideways friction applied to a shock added to its initial resistance is called stiction. Shorted form of static friction caused by two surfaces rubbing together. Modern prolink shocks move up and down and have no (or almost no) sideways movement, so I figure you must be talking about the front shock. I figure you are talking about stiction because:

as the suspension is trying to transfer a vertical force into a semi horizontal force...and there xtra fricton involved

Otherwise it seems you are talking about increased spring preload requirements and lack of preload on a weak spring is one reason why you seem to think you get 60% fork travel when cornering. Personally I would like to see a data trace on this behaviour occuring.

You still havnt mentioned if you are talking about front or rear

Its the use of the word digressive thats confusing me.

I've always heard it as low speed damping. That is high damping force at low speed, normal damping force at high speed. Not sure where all this sideways stuff comes into it.

[Brian d marge]

I ll quickly jump in here before I toddle off to bed,

All forces can be broken into 2 , a X and a Y force a vector and can be moved anywhere as long as you dont change the magnitue and direction of said vector
So A bike leaned over at 45 deg will have a force of a downward force and a horisontal X force in the direction of the outside of the Curve ( stiction is the force due to friction of the seal against the metally bit ...friction is a ratio between acting force and reacting force acting at 90 deg to the surfaces )

So if the horisontal component of the force is increased either through a greater lean angle or whatever , stiction will increase as the acting force on the metally bit of the fork has now been increased .

So Force is mass times acceleration ,,so if you soften the damping...... the SPEED of the shaft is greater , and will over come the stiction allowing more precise control ( as in the spring will absorb the energy and the oil will take less energy ...FOR HIGH shafts speeds only ,,as soon as the shaft speed comes back down ,,,the oil will take more of its share of the transfer of energy ,( the action of shoving oil through larger or smaller holes )

MX damping is a mixture , My front forks are digressive ,,I left the high speed shim stack intact and increased the low speed . by 2 x o.1mmx 16mm shims
A digressive linkage system I need to see a photo off..as I cant picture one now ...to late,,,to tired and half pissed ,,sorry folks long day !!!


Sorry I just bashed this reply out before crashing ,,,so any ( or if total crap ) technical foparas ( spanish for crap) ,,,see my Lawyers
Huey doo-em and How

Stephen

abd if it made any sence at all ,,you are drinking better shit than me !!!

[R1madness]

Thats cool, The standard suspension is a lot better than a few years ago, but the factory is a bit myopic they ( honda ) really dont know whats going on in the outside world ,,,( american honda I rekon is saving their arse!) look at this years tokyo motor show ,,,Retro ,,brand new copys of 20 year old shit !
Stephen

Hi Stephen. Yea man the factory skimps on the suspension to save a few $$$$$. Then the fast guys spend the extra cash on WP or Ohlins and the rest suffer by comparisum. I think all racing should be made cheaper by the introduction of a PURE PRODUCTION CLASS. Imagine what it would be like if you had to run std shocks and std valveing. Yes everyone would be slower thats true but maybe it would force the factorys to make their shocks and forks as good as possable.
Yea i know its a pipe dream but look at the one class racing from around the world where everyone is on similar machines and $$$$ dont count. AWSOME and CLOSE racing.

Retro is cool when ya get to my age (not ) and we are tha ones with the $$$$ (well not me personally) the factorys think. And since we (the old ones) are all suposed to be returning riders ( not me i have never been without a bike) we dont need fun or modern bikes The bikes they are showing are the same as the shitters i started riding on 20years ago. maybe i should not have sold my old shitters. They would be all the rage now hahahahahaha.

[R1madness]

Thats cool, The standard suspension is a lot better than a few years ago, but the factory is a bit myopic they ( honda ) really dont know whats going on in the outside world ,,,( american honda I rekon is saving their arse!) look at this years tokyo motor show ,,,Retro ,,brand new copys of 20 year old shit !
Stephen

Hi Stephen. Yea man the factory skimps on the suspension to save a few $$$$$. Then the fast guys spend the extra cash on WP or Ohlins and the rest suffer by comparisum. I think all racing should be made cheaper by the introduction of a PURE PRODUCTION CLASS. Imagine what it would be like if you had to run std shocks and std valveing. Yes everyone would be slower thats true but maybe it would force the factorys to make their shocks and forks as good as possable.
Yea i know its a pipe dream but look at the one class racing from around the world where everyone is on similar machines and $$$$ dont count. AWSOME and CLOSE racing.

Retro is cool when ya get to my age (not ) and we are tha ones with the $$$$ (well not me personally) the factorys think. And since we (the old ones) are all suposed to be returning riders ( not me i have never been without a bike) we dont need fun or modern bikes The bikes they are showing are the same as the shitters i started riding on 20years ago. maybe i should not have sold my old shitters. They would be all the rage now hahahahahaha.
Have a great xmas all.

[cowpoos]

no, I drew [or tried to] a vector diagram on what you are talking about. Somehow, you are implying that the bike increases its weight when it goes around a corner.

correct...it does increase its weight...how much...depends on how much speed is involved in the motion and the bike [G forces] speed

Only way you can compress suspension is to increase the mass of the object on top, or put a bump underneath - you mentioned no bump. So must be increasing the weight of the bike.

there are more forces at play than vertical ones...its hard to factor momentuim into drawings

Sideways friction applied to a shock added to its initial resistance is called stiction. Shorted form of static friction caused by two surfaces rubbing together. Modern prolink shocks move up and down and have no (or almost no) sideways movement, so I figure you must be talking about the front shock. I figure you are talking about stiction because:

Otherwise it seems you are talking about increased spring preload requirements and lack of preload on a weak spring is one reason why you seem to think you get 60% fork travel when cornering. Personally I would like to see a data trace on this behaviour occuring.

read Brian d'marge post below yours

You still havnt mentioned if you are talking about front or rear

this is irrelivent...as the forces are applied to both ends evenly...if they don't you going to be changing bike geomertry through the corner...so if one end is move alot more than the other you bike will be unstable

Its the use of the word digressive thats confusing me.

I've always heard it as low speed damping. That is high damping force at low speed, normal damping force at high speed. Not sure where all this sideways stuff comes into it.

think about it some more...

[TwoSeven]

this is irrelivent...as the forces are applied to both ends evenly...if they don't you going to be changing bike geomertry through the corner...so if one end is move alot more than the other you bike will be unstable

This cant be true. A rear shock does not have half the forces applied to it as a front unit would. Simply put, its got a bloomin great chunk of manganese/alloy reinforcing it. Also a rear shock isnt subjected to as much twisting force as the front is when the bike is turning, nor will it be subjected to forwards/backwards bending either. Even the weight applied to it will be different simply because of the bias tha chassis has.

yes, bike geometry does change quite a bit thu the corners.