Ok Suspension Gods, Weigh in on This.....

9 replies to this topic
  • RichB

Posted January 02, 2002 - 04:51 PM


I emailed a suspension shop that has been featured in at least 1 magazine, receiving a high grade on their work for the everyday rider. The subject was doing away with the mid valve. Here's what they had to say:

"The factories switched to mid stage valve stacks in the mid 90's because it allows more control over the oil flow. The lower adjuster actually has about 1/4 the oil flow that that the mid speed valve passes. Using the mid speed as a valve stack increases the possibilities for oil control over using only the lower stack. I would only remove the mid-valve if you were a 60 year old trail rider."

What do you guys think about that concept?


p.s. I will let the suspension shop I heard from remain anonymous.

  • motoman393

Posted January 02, 2002 - 07:28 PM


Well I cant give you a technical answer, but rather a "seat of the pants" answer! 2 months ago I was worried that if I removed the midvalve my suspension would bottom too easily on 100+ ft jumps! Well after removing the midvalves and installing RT's gold valves my forks are not only more plush but they also soak up landings much better! To give you an example: 5 days ago I cased a 90 ft triple by about 3-4 ft and thought I was going to wreck real bad...but my suspension soaked it up! I was amazed (if I would have had my stock suspension it would have been nasty) and then I realized that my $450 was well spent!

The shop that you are talking about is most likely MX Tech...they are the shop I would have taken my suspension to if I didnt want to do it myself (because all the reviews I have heard are all positive...and from what I have gathered on DRN is Jeremy cares about "the customers")! The main reason I did the Race Tech route is user friendliness...and it turned out with awesome results (thanks MX Tuner)!! Any suspension that is valved/sprung more towards your skill/weight will be better than stock...the question is, "who you gonna pick?" and "do you want to do it yourself w/no previous experience?" Good Luck,


  • MX_Tuner

Posted January 03, 2002 - 05:38 AM


There are a couple different schools of thought concerning this. I've had excellent results by disabling the midvalve and the cartridge valve. Others ahve achieved their desired results by using them. Neither is wrong, just different.

One problem with the midvalve is the fact it can change as the shims get weaker. This means your nicely revalved forks suddenly got too soft. Now you have to send them back to get them fixed. This repair is not a free service, either. By disabling them, this varialbe is eliminated.

  • Ga426owner

Posted January 03, 2002 - 06:22 AM


Yanking the midvalves out was the best thing for my forks. I guess either as I was getting faster or the shims were wearing out. The fork action became vague, meaning the bike felt different each time I traveled over the same exact part of the track. Also the bottoming was increased even at 2-4 out on the compression, ouch on each landing. Now w/o the midvalves the bike feels more predictable the bottoming resistance is increased & my confidence has increased 75% to do things I would never do before. Also using racetech gold valves w/ master installation/assistance from MXTuner ---- This was the most cost effective fix for my bikes suspension. So, I do not share in the advice of the "Unnamed Suspension shop".....But, to each his own with suspension advice, this I have learned from trial & error.

  • DaveJ

Posted January 03, 2002 - 08:31 AM


I think you have your answer, and I'll just add my vote.

This guys needs to understand that we agree that removing the mid-valve would make the suspension too soft. Just like it gets when the mid-valve wears out.

The fix is to remove it with a modification to the cylinder valve.

However, even though I don't run one myself, I still think the best approach is to probably re-design the mid-valve so to allow a variable of stacks without the issue of failure. That way you can benefit from the initial purpose of the valve.

Perhaps you can send this guy the link to this site. Allow him to defend his ways.


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  • John_Curea

Posted January 03, 2002 - 12:00 PM



Well said.....

When you remove the midvalve you are greatly limiting the "range of adjustability".

It is pretty basic, we are trading performance for simplicity.

Think about the variables when "tuning" the compression circuit on a late model YZ fork;

1. Base Valve Piston Port Design
2. Base Valve shimstack
3. Base valve bleed circuit
4. Midvalve Compression shimstack
5. Midvalve Compression shim stack "float"
6. Midvalve bleed circuit
7. Cylinder valve
8. Oil weight
9. Oil height

Each one of these "variables" has a certain amount of performance and adjustability.

Now if we remove any one of the "variables" we loose a certain "range of adjustability" and performance.

Without a doubt the job of tuning gets easier if we remove a variable, its a trade-off.

Out of all the variables, the midvalve is what usually frustrates most tuners. Combining the right amount of float with a good shim stack build takes time and testing. If we build the shim stack too "soft", it ends up warping and loosing the ability to dampen. If we build it too stiff, it acts like a check plate.

The testing is time consuming, because even the smallest of change in the midvalve requires a complete teardown.

Think about this, how about we design a midvalve shim stack for a gold valve? Can it be done and make it better? I bet you with some time and testing, we could it get it to work real good. How much better, only one way to find out.

A midvalve that is well supported will last...

Well, you knew I could'nt keep quiet on this subject :) :D

Take Care, John

  • DaveJ

Posted January 03, 2002 - 12:54 PM



Cool post dude. I agree.

There are some on this board that are using modified mid-valves that just may be working. I tried some stuff last summer that made things better, but never proved to be as stable as removing it.

I would agree I lost control over mid-speed, but I gain in other areas. Those gains are substaintial, which supports the RT approach.

Can we develop a mid-valve assembly that works? I think so.

What I would really like to do is build a bench tester where one could profile and plot inputs and responses. Get scientific...ya know.

Be real cool if you lab this stuff to near perfection. Then ride away smoothly.


  • MX_Tuner

Posted January 03, 2002 - 05:12 PM



Good point about building a stack to work with the GV's, as long as it wouldn't wear or weaken with age. I see your point about removing variables limits adjustability but the fact of the matter is as long as you get the results you desire, why hassle with them?

I like DaveJ's approach about getting dwonright scientific with monitoring changes scientifically but the $64 question is........ how?

  • John_Curea

Posted January 03, 2002 - 06:10 PM


And the answer to the 64.00 question is.....

Well, its more like a 30 grand (minimum) answer.. A shock dyno that can run forks.

This is the next step in testing. I think with the right set up, alot of the initial design work can be completed on a dynonometer.

Actually, I think the best would be a mobile unit, that can be transported to the race track. Then we would be able to do real world testing in comparison with the dyno readings.

Well, thats our goal anyways, I'll keep you posted...

Take Care, John

  • ossagp

Posted January 03, 2002 - 09:08 PM


Please keep us informed. Suspension is one of the things that has grown in it's ajustability by leaps and bounds. Simple in concept and so many variables in use. The physical laws governing it must have been written with the establishment of the universe. Testing and using them is the tough (tho fun and rewarding) part.

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