Spring Rate Preload and valving!

[fishhead]

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

 

[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. :eek:

 

[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.

 

[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.

 

[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.

 

[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.

 

[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.

 

[tmoney]

dual stage mid-valve piston

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?????

 

[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.

 

[marcusgunby]

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 :rotfl:

 

[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.

 

[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.

 

[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.

 

[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.

 

[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! :eek:

 

[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.

 

[Wile_E_Coyote]

Too many variables

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.

 

[Robcolo]

Springs and things

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.

 

[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.

 

[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

 

[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.

 

[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.

 

[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

 

[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.

 

[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