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Spring Rate Preload and valving!
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Posted by: Jeremy Wilkey---------------------

Hey all these polls seem to be really cool. I want to conduct another poll and get a veiw for what most people feel is the best way to attain ideal function based on exsperience.

Ok.. Since you can't vote twice, vote in the category that best suits your riding and the results should reveal a pattern. Please state your reasons. As always I will post my veiws as it it unfolds..

Regards,
Jer

Posted by: KawieKX125---------------------

I picked light springs heavy valving for MX because from what I understand, the KX I ride has light valving and I have to overspring it to get any sort of bottoming resistance. The problem I get from the heavy springs is harshness and headshake. From my limited knowledge and what I can try to deduct from the above info, the light springs would keep the suspenders plush with the heavy valving providing plenty of bottoming resistance and making the suspension controlled on sharp bumps.
Am I even remotely correct?

:think

Oh ya, if it matters I ride on VERY rough tracks(hardpack with rocks) with big jumps and some pretty tight supercross style rythm sections.

Posted by: motojunkie---------------------

I picked ideal spring/midrange valving because it seems like that would be the most versatile setup. Light springs/heavy valving is how my 520SX came set up, and I can't get an optimum MX setup out of it. Heavy springs/ light valving, it seems like you wouldn't be able to get proper preload for your weight. Also, I'm not sure here, but wouldn't that cause it to blow through the stroke easily. Oh well, I'm interested in seeing what the "correct" answer is.

Posted by: KawieKX125---------------------

I don't think their is a correct answer. I do have trouble with preload and sag, but I am super-comfortable with ALOT of sag. Kindof Charmichael-esque in a way? But, heavy springs with light valving is definetly not the way to go as evidenced by the fact that my bike bottoms on some jump takeoffs. Granted they are steep, but it still does not work.

Posted by: motojunkie---------------------

I realize that riding style, and rider preference will dictate the setup, and that there won't be a correct answer - that's why I put it in quotes. What I meant by that is that I'm interested in what the experts believe is correct. I'm sure Mx-Tech, Race Tech, Pro-Action, Factory Connection, etc. tuners will have a little different philosophy on this, and I'm curious as to why. Thanks Jeremy, I really like these discussions, because as a suspension rookie, I learn a lot about suspension tuning.

Posted by: Hogwylde---------------------

Elephino!!! That's why I look to people like YOU to tell ME how to set up my suspension for the kind of riding I'll be doing. Planning on sending ya my forks and shock this winter for some reworking. Hope ya can get me dialed in!!

Posted by: Jeremy Wilkey---------------------

I think I gave away too much... My purpose in doing this is A.) get more people involved and two hopefully generate good strings... I think the important thing to consider is that obvously I have my opion but really as long as your thought process is good we like as forum readers like hearing other ideas.. Since i've had to travel so much this year I have not been around as much, so I've tried to evolve the way I moderate, do more with generaating good ideas more than answering every question... You guys have done a great job at that..

Anyway what do you all think might be some intresting alternatives to the options listed above?

Posted by: KiwiBird---------------------

HS - light valving, heavy springs, fairly light preload. I like to spring for my weight with maybe 5mm preload and then adjust valving to suit.

Posted by: 00kawa125---------------------

I voted for the ideal spring and the mid-range valving. I have only six months experience with motorcycles, but here's my opinion anyway.

From what I understand, from this forum, is that the valving is speed sesitive and the spring is position sensitive. The spring it seems would keep the suspension higher or lower in the stroke than the valving would. By using a soft spring it would allow the suspension to ride lower in the stoke reducing the amount of travel. A heavy spring would ride higher thus increasing travel. With less travel (soft spring) the valving would have to be stiffer to reduce bottoming, with more travel (heavy spring) the valving could be tamer, for the same level rider.

I would think, for a novice, the soft spring would be good because they would not be using all the travel anyway. Even the valving could be softened. But for a seasoned rider the soft spring would be very harsh because they would use the travel causing the valving to be harsh to keep from bottoming.

01 YZ125

Posted by: MACE---------------------

If the enduro choices both have light springs, there's not much opportunity to argue:D . My experience with heavy (commonly considered "optimal") springs is that they are too jarring for rootnrocksnruts. Physically painfull after a day or two in the saddle. With "excessive" amounts of preload or low oil levels I can get the same static wheel rate as the heavier springs but the reaction at the bars is less when I roll over that two inch rock.

Light damping works in some conditions like rocks but is limited in it's versatility. There will eventually be a section of nasty whoops and that light valving ain't going to cut the cheese

in the whoops. Wanna know the damping curve I want? I'll design an inertial valve that reduces damping to near zero under high acceleration. What this would do is let the wheel move freely when it gets a sudden jolt and then smoothly apply damping as the acceleration spike subsides - arresting further wheel motion but avoiding the spike. All this needs to be is a spring and a mass driving a spool valve or perhaps a needle. Put that in your pipe and take a good drag......

It's interesting to see how many hits these polls get compared to the number of posts. Come on guys. Tell us what you think and more importantly, WHY you think what you do.

Posted by: KawieKX125---------------------

Is someone willing to comment on my bass akwards theroy of why light springs and heavy valving would work best for me? I am dying to know if I am correct, remotely?

Posted by: marcusgunby---------------------

Arron i adree with you because works KTMs have that arrangement and they are the best suspension IMO.I like the softish spring heavy damping.Light damping even with stiff spring will not work in mx as the damping contols the spring-you can have a silly stiff spring but without sufficient damping it wont be any stiffer than a light one when landing off jumps etc.

Posted by: KawieKX125---------------------

OK, I am not far off in my reasoning! I was always told the .41's I am using with a 4.8 is WAY to stiff for me yet I bottom consistently over most jumps and takeoffs!

Guess when I get the new bike I will revalve. The only problem I can think of with this set up is a "dead" feelig in the top part of the stroke and packing problems as the spring will not have much stoored energy.

Posted by: John Curea---------------------

Man, I've been away too long.........

This is a really good thread.......

For woods riding, I would go with light springs and light valving. I recently raced a 4 hour harescramble, I tell you, during the last part of the race, my suspension couldnt have possibly been plush enough. I went into a survival mode, things got a little blury and I picked the wrong tree to go around, major center punch (somebody has to keep the handlebar manufacturers in business)......

Anyways, in a woods enviroment, I think for most riders, need a softer spring and valving than MX. (although I have a friend who likes a full moto set up in the woods, I dont think he has any pain receptors in his brain).
A quick run in the woods is one thing, but when you are in the saddle for a couple hours at one time, an MX set up will beat you up. 90% of trail is usually rocks and roots, a whoop out section or jump section are usually far and few in between. I would rather valve and spring softer for 90% of the ride and deal with moto stuff at a slower pace, I beleive your lap times will be faster.

On the flip side, I believe motocross needs a heavier spring and heavier valving. Again, most motocross races last about 15 minutes at the most (excluding national events) we can valve and spring heavy for the extreme sections of whoops and jumps. An average rider can hang on pretty strong for 15 minutes, and we can valve and spring for max speed through the whoops and also handle the jumps (also handle the mis-timed jumps safely).

Mace, lets kick that inertial valve idea of yours around some more......

Take Care, John

Posted by: Yamamoto---------------------

This is because
I am a light guy on an MX bike, but like to be versitile so that I do not have to ajust much to adapt to woods riding or big jumps.

I also fine this set up with MX springs and lighter valving to be good because the stiffer springs help keep the ride height up and therfore making the suspension responsive to the small stuff but also allowing big stuff with out harsh bottoming.

My opinion on bottoming is that its normal, if you do not bottom out you are not useing 100% of your suspension and that means you are wasting it.

Posted by: MACE---------------------

Quote:

Originally posted by KXVET#207
Mace, lets kick that inertial valve idea of yours around some more......

This has been keeping my brain grinding when I should be sleeping. I find that Edelbrock has something similar on a car shock. I think the Edelbrock shock might have an acceleration sensitive rebound circuit which seems backward to me. Check out Edelbrock's execution:

http://edelbrock.com/automotive/ias_shocks.html

I've got a few different ideas for actual hardware. What I don't have is a good idea of what sort of accelleration should trigger the "dump". I need to know that to size the mass and resisting spring. Does anyone think this is just a totally stupid idea? I think it has a lot of potential.

Posted by: John Curea---------------------

MACE
I did a quick look at the info.......

I think the acceleration rebound circuit would work, I beleive that fork packing would be greatly reduced. You would be able to run the rebound as slow as you want and still get quick extention of the fork over whoops and potholes without the front end diving sensation.

I applaud your "reinventing the wheel" attitude, I have been kicking around an idea of having a variable displacement piston rod. With the narrowest part of the taper in the center of the rod. This would give you an initial reduction of fluid flowing through the base valve for the first half of fork travel, then increase the flow the further you go into the stroke.

....This has been keeping my brain grinding when I should be sleeping

.......I know that feeling........

Posted by: P_Taylor---------------------

Quote:

Originally posted by KXVET#207

variable displacement piston rod. With the narrowest part of the taper in the center of the rod.

[/B]

any ideas on how to seal the top of the cartridge with this rod?

Posted by: John Curea---------------------

P_Taylor

That's what keeps me awake...........

Posted by: Esp1---------------------

MX: Ideal spring/ midrange valving
-I think heavy valving/light springs will not be sensitive enough in begn of stroke. It will use too much of the stroke if you like to keep the free-sag.

By the way; What is Theoretical Ideal Springs? Why is the theory not the same for MX,HS,Enduro,SX?

Posted by: Yoken---------------------

When I race a MX track, I tune my suspensions mainly for the turns. In Cyprus, most of our tracks are made of hard clay and rocks with supercross type jumps and tight turns. I definitely go for the following setting:

- relatively hard springs, but with low pre-load,
- moderate low speed compression damping,
- light high speed compression damping.

It seems that the low pre-load (3 to 5mm on the fork springs) keeps the fork plush and more responsive on small bumps. Also, it allows the front end to dive moderately when I set up for a corner (I need that because my KX does not turn if the front end rides too high).

Than the springs get harder as the fork goes deeper into the stroke. This usually gives me sufficient bottoming resistance.

I need moderate low speed compression to keep both wheels on the ground in the turns.

The light high speed damping helps me to reduce "vibrations" in the bar as I ride a high speed section with little bumps and rocks.

For those slippery conditions, I like to run a low air pressure in the tires (around 800gr only). And I install 2 inner tubes to increase the resistance to puncture.

Posted by: rollingp---------------------

censored

Posted by: michigan---------------------

Sheeshz. If I didn't live in Michigan this would be easier. I weigh 220 withOUT gear, so heavy springs are in order, just to achieve the proper ride height. I only ride in the woods, so in most places I'd be happy with heavy springs and light valving, but Michigan woods are filled with big ole' whoops.

Actually, I don't care what's inside them. I just want them to work. Before the snow melts, I'm sending them out!

Posted by: Fred T---------------------

Quote:

Originally posted by michigan
Sheeshz. I only ride in the woods, so in most places I'd be happy with heavy springs and light valving, but Michigan woods are filled with big ole' whoops.

Is that what those are? I thought we were just riding up and down hills!

Posted by: James---------------------

Is this a trick question:think

Don't you always want the "Correct" spring which may be heavy or light depending on the weight of you and your bike and then the valving to match the springs and the riding you are doing??

Right now, I need stiiffer springs and stiffer valving in my xr400 because the frame is always dragging the ground.

Posted by: fishhead---------------------

how about none of the above
enduro- heavy springs, less preload, oil height to bottom softly, and valving just to keep it stuck

Posted by: WoodsRider---------------------

For both enduro and hare scramble I'd have to say it depends on the geographical conditions. I've lived in different parts of the U.S. and I can honestly tell you that what works good in Michigan sand whoops will beat you to death in New England rocks. I used to hate sand whoops until I started riding in New England.

Posted by: Eric T---------------------

Heavy springs and light valving wouldn't give you enough rebound damping, since the stronger spring is fighting against it. To go to a heavier spring, you need less compression damping and more rebound damping.

Posted by: Lorin---------------------

Spring for your weight and valve for your conditions (enduro-wise). For the rigors of mx, heavier springing may be called for due to the big landings, etc.

Posted by: jzyz---------------------

I'm just learning about suspension so my 2 cents is that you want springs that will support the bike and your weight for the conditions your riding and let the valveing control how the spring react.

Posted by: Barbarian---------------------

I'd say enduro should be as stiff as HS. In a HS, you pace yourself for a couple of hours, where as in an enduro, you are going balls out for 20-40 minutes at a time.
HS's are on rougher, more beat-up terrain though, so it kind of evens out.

Posted by: Shig---------------------

I guess it's all relative because one guy's stiff is another guy's soft. For MX, I'm partial to heavy springs and light damping. I bought stiffer fork springs for my CRF and backed the compression out to almost full-soft. The bike feels far more controlable at high speeds because the tire actually follows the ground now. Rebound damping needs to be moderate, but now that it's dialed-in, arm-pump and headshake are minimal.

For a Clydesdale like me (220 lbs in gear), light springs require too much compression damping to keep the bike from packing and bottoming. Light springs and heavy damping reminds me of my 92 CR 250, stiction, stiction and a smidgen of stiction. Also, I don't like the way light fork springs feel on braking bumps, pucker jumps and steep jump take-offs. It's like riding a 230lb stink bug, or perhaps, like riding a 98 KX 250 with stock (progressive) fork springs.

Posted by: tmoney---------------------

John, this reading is great. Thanks to yourself and Jer for facilitating "out of the box" thinking. I myself am no suspension guru but enjoy thinking about how to get what I want..jer is helping me now sort out my issues and thankfully so, as I was about to try a stack that was prone to fail....

Anyhow...would a dual stage mid valve piston work?

First piston would mimic what is typical today...ports leading into a valve stack arrangment that has designed strength and deflection to suit the initial desired action (ie. plush on low to mid speed hits with dampening only moderated by the first piston/valve stack...second piston would be smaller in diameter to allow fluid to travel past the entire piston body under low to mid speed hits. As the assembly moves through the fluid under high speed/high acceleration the fluid would not be able to bypass the second piston entirely, thereby finding the path of least resistance via ports and a second valve stack which could be designed to dampen only the high speed/high accelerations. This could allow a fork to be plush but still take the g-outs with sufficient bottoming resistance.

Could agrue this is the same as 2 stage but there has to be some advantages to having a piston/stack arrangement for low and high speeds?????

Posted by: georgieboy---------------------

Or the solution of a high speed/low speed adjuster same as on a shock. Have seen it on an ohlins, but perhaps every factory is now working with it?
With a spring they preload the valve stack. The stack is considered mid/high speed controllable. The lowspeed is controlled as it is today with a needle.

Posted by: marcusgunby---------------------

Quote:

Originally Posted by tmoney

John, this reading is great. Thanks to yourself and Jer for facilitating "out of the box" thinking. I myself am no suspension guru but enjoy thinking about how to get what I want..jer is helping me now sort out my issues and thankfully so, as I was about to try a stack that was prone to fail....

Anyhow...would a dual stage mid valve piston work?

First piston would mimic what is typical today...ports leading into a valve stack arrangment that has designed strength and deflection to suit the initial desired action (ie. plush on low to mid speed hits with dampening only moderated by the first piston/valve stack...second piston would be smaller in diameter to allow fluid to travel past the entire piston body under low to mid speed hits. As the assembly moves through the fluid under high speed/high acceleration the fluid would not be able to bypass the second piston entirely, thereby finding the path of least resistance via ports and a second valve stack which could be designed to dampen only the high speed/high accelerations. This could allow a fork to be plush but still take the g-outs with sufficient bottoming resistance.

Could agrue this is the same as 2 stage but there has to be some advantages to having a piston/stack arrangement for low and high speeds?????

that sounds like a pds shock setup and no one really likes those-lets not introduce them to a fork

Posted by: Danger---------------------

Ahh wrong. With the addition of a Terry Hay telescopic needle and a P20 spring, my PDS is the best rear shock I have had.
For what its worth, I run heavier springs with valving to suit, and the only adjustment I make is to go lighter four clicks on the fork rebound for MX than for woods. Nice two stage stack in the forks along with appropriate mid valving and rebound reshiming and oil weight and height with drilled tubes and cones and a few other tweaks have sorted my KTM's suspension, which was terrible in stock form.

Posted by: Crash 142---------------------

I think for MX, ideal springs, leaning too light rather than too stiff, with stiff valving. But I think it depends on what bike you're on, too. I have never felt a need to change springs until I got my 2004 RM 250. The bike is great, and very responsive. I'm 160 pounds, and with the stock springs it was bouncing or 'bucking' coming into the corners. Now with lighter springs front and rear, and with the clickers stiffened up, it feel smuch better. It feels more 'calm,' where before it seemed like it was springing back up too abruptly. And yes, I played with the rebound, but then if seemed to pack down and even bottom going through the braking bumps.

Now the bike is calm and perfect. Maybe it rides lower in the stroke, but it feels good that way. As for bottoming on jumps - the stiffer valving will start working as soon as the bike touches down, so 'riding low in the stroke' shouldn't hurt bottoming from jumps much (yes, I know the lighter springs will).

It seems real calm now entering corners in the braking bumps, and also very calm and 'predictable' riding through the corners.

The only downside I've felt is the bike seems to compress a lot on jump faces. Not sure if this will turn out to be a bad thing or a good thing. The bike still jumps neutrally.

So my vote for MX set up is 'ideal'/soft springs with stiffer valving.

Posted by: fishhead---------------------

Quote:

Originally Posted by fishhead

I say the same for enduros although this option was not on the list. In our part of the country the enduros are usually on much rougher terrain than a HS.

It is interesting that Mace and I ride the same events and terrain and his perception of heavy springs with light preload is exactly the opposite of mine. I run lighter springs than a mx guy would to be sure.

For valving I like it fairly stiff on the low speed section so it will handle whoops, rollers and g-outs but to be plush over the square edge stuff like roots and rocks. It seems intuitive that the fork should ride high in the stroke to take full advantage of travel.

I'm curious what the general opinions or consensus is on the best way to accomplish to accomplish this, a single stage stack with a fairly stiff ls section and quick taper to the hs section or a 2 stage stack with a thin crossover.

Posted by: Crash 142---------------------

I want to change my answer. I experimented with softer springs, but have gone back to stock and the bike feels better. I'm running the clickers much softer now, and the bike is working better than ever.

The light springs felt good coming into the corners, but didn't feel as 'confident' on the high speed straights. I know 'confident' is not the word to use for a bike, but what I was feeling was hard to explain. It didn't feel unstable with the softer springs, and it didn't have headshake, it just... I didn't feel like I was 'ready for anything' at speed.

The bike also feels much more 'solid' (in a good way) when hitting the faces of jumps with the power on. Also lands nicer. It's always jumped perfectly neutrally.

I'm back to the stock springs (maybe a touch heavy for my weight) and softer clicker settings.

Posted by: tjswigger---------------------

I think it's easier to tune the valving to work with with the spring than it is to try and compensate for too much or to little spring.The idea is to find a balance pointwhere the parts work together not overdo one and compensate with the other.Oil weigt is in this equation too!

Posted by: DWreck---------------------

I'm another one who believes in the spring for your weight, valve for the conditions. Of course it gets complicated when you ride one bike for all conditions like me. When I had my suspension done asked for a set up for 90% woods, 10% moto and am happy with what I got. I would like to see a comparison showing recommended woods valving/ what I have now/ and moto valving to see how mine compares for curiosity sake. The valving does seem a little light for moto at race pace and I can tell I don't have as much bottoming resistance as before but my bike handles slap down landings no problem now and it wasn't that way stock.

Posted by: Wile_E_Coyote---------------------

Hi, I’m new to the forum but not new to the sport. I usually keep my opinions to myself, but I’ll share it in this thread.

IMHO, there is no answer that can be correct every time. That’s why a professional suspension tuner is needed to eliminate the guesswork. When you consider the variables: oil viscosity, oil composition, oil volume, spring rates, (springs that are not rated properly), preload, cartridge design, piston and base valve design, bushing tolerance, mid valve differences, top out springs, proper weight balance of the bike, not to mention seal composition and stiction. I can go on and on, but the bottom line is that with all these variables, it takes an experienced tuner to get it right consistently. There is no magic setup. Experience and testing is the answer.

I personally think that position sensitive dampening is a good thing. That is if it is set up right. Most people confuse this with speed sensitive dampening which is what most forks are. For a position sensitive setup to work the ride height must be correct. I've only seen this done effectively when the compression is in one fork and rebound in the other. Many people think that the conventional zokes in the 90's were the best feeling forks ever made. My memory is fading but I think they had some type of position sensitive system.

Personally I like the 1989 KX 46mm conventional cartridge forks for overall feel, (my age is showing), anyone else like them? Recently I am becoming a huge fan of the new twin chamber forks; they are destined to be my all time favorites.

The concept of an inertia valve for off-road/mx may be a waste of time. Think about the forces that go on during the suspension action. You may need a microprocessor controlled valving system to determine the exact inertia points and vary them while monitoring the position and rate. Is the future of suspension electronic? Please let’s not go there. Now that would keep me up at night.

Spring for the weight of the rider, preload varies with weight of the bike and application. Valve for the most progressive feel and the best control, make small adjustments where needed and keep a log of everything you do so you can back track need be. Keep the fork oil clean and fresh, train harder and stop blaming the bike when it's your physical conditioning that is causing the problem.

Thanks Jer for keeping everyone thinking.

Posted by: Robcolo---------------------

I'm now riding a KDX. With stock .35 fork springs the bike is wonderful in the nastiest of conditions -- 1st & 2nd gear stuff.
I did install Gold Valves to eliminate severe spiking from the stock on-off base valves. Get into 3rd or 4th and try going around a flat corner the bike will wash out every time. INstalling .38s up front completely elilminates the wash-out tendency but now it's like my KX in the nasties-- lots of work. [maybe I should try .37s?] Anyhow I'm playing with a dual rate spring. Stock .35 steel springs in there then I've added a subtank, micro pressure gauge and small air pump and can add or subtract air quickly as the terrain changes. I'm still playing with subtank volume but it seems to overall work pretty good. major problem i'm having is a bit of excess stiction from the added air pressure squeezing the seals to the fork tubes.

Posted by: Wile_E_Coyote---------------------

Add and subtract pressure on the fly, very cool. I like to see people trying new things.

So you feel that lighter springs make for a better off-road feel? Did you check the preload on the .38's? Seems that the .38's correct your ride height.

Did you try the .38's with a lighter valve stack?

If you want to get into it, try the .38's at 4mm preload, then use a .05 thicker crossover shim. If you dont have a thicker one, try 2mm smaller diameter. Dont change anything else.

Or just continue as you are, seems that you have it under control.

Posted by: lemons r yellow---------------------

Well I will say this .
Jeremy schooled me hard last year and give me a new found respect for his knowledge.
He was kind enough to work with me a bit between his busy schedual.
I am a fairly new to the scene tuner learning and working towards doing suspensionfull time for a living.
After discussing and switching over to some of his valving recomendations I kept complaining about spikes in my Forks.
The springs checked out good but Jeremy insisted that I go softer. I kept putting it off and working with the another set of forks to compare.
In the end I finally found enough cash to buy myself a set of ligter springs and install them with some of Jeremy's education on valving.
what a difference and it left me eating crow and gave me a whole new light on what is going on inside a set of forks.
I think optimum or as light of spring you can get away with with good valving is the way to go!
thanks for the education Jeremy
Cameron

Posted by: Lorin---------------------

I went to heavier springs \ moderate valving and this worked well when riding aggressive. The problem I ran into is with the heavy spring rate, you have to add considerable rebound damping to work well in the turns, and the rocks and roots deflect more than I like. I ended up going to the stock springs (one step lighter than reccommended for my weight) and adjusting the oil height and compression clickers to get a better ride. I am still tuning and may add a little preload on the fork and\or adjust sag a little, but am at least heading in the right, general direction. At least this way, I can soften up for the occassional tight, rocky ride.

Posted by: Jeff Howe---------------------

I did a comparison of lighter springs with more preload and my regular springs with average preload. The light spring/more preload "felt" ok but the bike handled horrible. The regular spring/average preload "felt" as good BUT handled WAY better. I could never get the lighter spring/more preload setup to turn well at all and it didn't track very good either. I was always wondering just what kind of surprise the front end would throw at me next. It was completely unpredictable and down right scary at times. Put me on my head more then a few times in corners and ALWAYS wanted to climb out of ruts. So, while it may "feel" ok on the track it's not good for handling in my opinion.

Posted by: tzr8cr---------------------

i like my setup for hs a progressive spring soft on initial inpact but gets stiffer when close to bottoming gives me alot of feed back on what the front is doing and a midrange valving so depending on terrain i can go a little stiffer or softer for compression and or rebound. in the mud i like it softer on harder ground a little stiffer but still forgiving. mostly in the middle is best for me for all around environment. just my set up i think if you find a setup your confident with stick with no matter what others might say. confidence is in my opinion 50% or more of riding

Posted by: JBlinky67---------------------

Being an enduro racer, I chose the "HS heavy valve light spring". The best setup for me is, and has always been, use only enough spring rate to achieve correct sag. Stiffer spring rate will only make all those small bumps feel like supercross whoops to me, even with Tapers. I choose to valve my stacks to give the best high and low speed feel wether I"m on the trail or on a track, with priority on the trail. Use light oil too. When it's right, a few clicks is all it takes to ride different terrain.

Posted by: pobit---------------------

I would say it depends on if your a fast rider or a slow rider. Fast guys are more intrested in control than compliance on small stuff so the heavy springs with more low speed keeps the bike from see-sawing at speed and keep the bike level in whooped out turns. Slow guys feel every bump and prefer soft springs with less low speed and more high speed for when they get in over their heads. Mushy suspension works for them because they don't ride fast enough to where the see-sawing affects them. As far as spring selection in general, my thoughts are the free sag is more important than the race sag if I have to choose between the two. A typical linkage bike works best when the free sag is around 30mm.This gives the best compliance over bumps and the most grip. If you go too far from this setting the rebound doesn't work and the bike will lose traction by rebounding too fast and the ride feels hard. Same goes for the front. Not enough free sag and the bike wants to spring back too fast when hitting a bump in turns. If you turn in the rebound to correct for this the fork packs on biggger impacks and gives you a jolt. Dave

Posted by: Roost1---------------------

Have you ever watched a really smooth rider? They make it look like they are almost floating over everything. For the rest of use we need suspension to compensate for the wrong line or a cased jump for example. This is why the suspension has to be personalized to rider. For me being a woods rider I prefer a spring towards the softer side and control the speed with valving. It may not the best set up for whoops but I hate them anyway so I just pin it and ride across the tops

Posted by: MRW---------------------

Quote:

Originally Posted by Yoken

When I race a MX track, I tune my suspensions mainly for the turns. In Cyprus, most of our tracks are made of hard clay and rocks with supercross type jumps and tight turns. I definitely go for the following setting:

- relatively hard springs, but with low pre-load,
- moderate low speed compression damping,
- light high speed compression damping.

It seems that the low pre-load (3 to 5mm on the fork springs) keeps the fork plush and more responsive on small bumps. Also, it allows the front end to dive moderately when I set up for a corner (I need that because my KX does not turn if the front end rides too high).

Than the springs get harder as the fork goes deeper into the stroke. This usually gives me sufficient bottoming resistance.

I need moderate low speed compression to keep both wheels on the ground in the turns.

The light high speed damping helps me to reduce "vibrations" in the bar as I ride a high speed section with little bumps and rocks.

For those slippery conditions, I like to run a low air pressure in the tires (around 800gr only). And I install 2 inner tubes to increase the resistance to puncture.

I know lots of people that love this type of setup

Rocks, palmetto`s, same differance, both slippery and hard

Posted by: kiwijohn---------------------

Gidday people... I love threads like this! Much like the world famous "Which Oil do you use?" threads, this one is full of fact, fiction, opinion and reality.... awesome!

I have a few questions after reading all of this , so if you have any extra info please feel free to put me on the right track!

Two days ago I bought an 06 RM250 from my buddy after riding a 06 RM125 for 3 months, and before that an 05 Sherco 450 .

The 125 was pretty good in the woods, unless there were steep hills around

, and the Sherco was great in even the ugliest terrain. But I think the soft suspension made the bike feel heavier than it actually was?!

Question one is: Did the 125 feel good to me because I was heavy enough to break through the MX valving?

The 125 is MX bike set up for - I'm guessing - 150lb riders? While I'm about 93kg (205) plus gear. The Sherco would be set up for an 70 - 85kg (155 - 190lb) rider?!

The 125 spring weights are a mystery to me... but the valving would be MX in set up. The Sherco springs had to be heavy enough to support a heavy bike but had light valving at both ends too.

SO - the question I need to think about for my RM250 is: "If I reduce the valving to a softer setting, like the Sherco, will the heavy springs overpower the valving? Would I be better with softer springs and softer valving (That's my guess).....
Or, if I leave the stock springs in - Will I need to have a my rebound heavy enough to cope with the strength of a stiffer spring?

In my little brain I don't mind if my springs go through the travel quickly to absorb ruts and rocks etc, but I don't want them to shoot me into space on the rebound either!!

Sorry if I sound a little, confused but that's because I am!

Cheers

John

Posted by: Filthy_McNasty---------------------

Quote:

Originally Posted by MACE

Wanna know the damping curve I want? I'll design an inertial valve that reduces damping to near zero under high acceleration. What this would do is let the wheel move freely when it gets a sudden jolt and then smoothly apply damping as the acceleration spike subsides - arresting further wheel motion but avoiding the spike. All this needs to be is a spring and a mass driving a spool valve or perhaps a needle. Put that in your pipe and take a good drag......

.

Isn't that in essence how Yamaha's SSS damping system works?

Posted by: MRW---------------------

There are forks like/similar to what "mace" speaks of. They are for mountain bikes and perhaps other types of vehicle's.

"Fox" make a set of forks called "f100x" and the have this type of inertia valve system/principle/concept idea going on.
They are old tech. by now(2006), but just the same, they are
cool

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Spring Rate Preload and valving!

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