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midvalves?
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Posted by: Fred T---------------------
Go easy on me here, I'm still learning. But can anyone explain the advantages of having midvalves in a woods set up? I'm in the process of adding them into the forks but I just wanted to be real clear on what to expect from my forks with them added. My bike is basically of 1995 vintage technology wise so I'm paying Jer to bring me up to as current as he possibly can with what I got. KDX 220. I'm trying to chase these damn fast kids through the woods on this trick 2002 technology and some funny orange colored bikes. Thanks for your kind and understanding comments. I refuse to get old. 
Posted by: Jeff Allen---------------------
You've got a few years on me and I can't keep up with you old timer
Posted by: RTL---------------------
Excellent question Fred T.. It's been a while with no replies. How about a brief description from the man himself. Give it up Jeremy..
Posted by: Jeremy Wilkey---------------------
Well actually lets go back farther.. More like 86 level technology.. Sorry..
Anyway here is the breif description..
The basevlave is ofcourse only regulating the volume that the rode displaces. This is a small volume. This small volume actually can be used to your advantgae if you configure everything corectly.
Look at some theroy first.. In suspension we want low speed compression to control chasis movement, and create stablity. We also need traction.. To some excstent traction is a mix of low and high speeds, consider it in some ways responce...
Midspeeds, these control bottoming.. Uper midspeeds also begin to impact the suspensions ablity to absorb bumps.. By the time we get to high speed we wish we could actually go the other direction.. However we can't so for the sack of bottoming and stablity we lose some ablity to absorb bumps.
Now what about the basevalves role in this.. Since we have a base-valve and it controls on average 25% of the total oil volume what can be done to configure it. Quite simply we revalve it for more low speed in the Case of the KDX replace it. The new piston is hopefully more effiecnet and not only makes the lowspeed stiffer, but also makes it more senstive, so as fluid flow increases the valve does not over or under flow.. (This is a very complex topic for another string..). This gives us in theory the best chracteristics, but unfortunely we can't reduce damping rates as the speed increaes effciently.. So we pay a certain price of harsh and unresposive fork action..
Now the midvalve.. Since the midvlave has 75% of the forks oil traveling through its shims it is much less prone to being over sensitive.. We can let it open unrestricted a certain amount. (Or float) This deteremines at what speed it begins to influence control. Then as speeds increase we can create more midrange damping this gives use better use of the basevalve. Now as speeds increase further the valve can be set up to offer little to no increase in damping rates.. So the curve faltens ouot sooner.
This in turn allows us to lower the basevalves coeifcents and produce less midspeed their and subsequent decrease in high speed is a perfect addtional advantage. Now the system works more effecitnly as a whole and tyhe rider gets a better ride..
Regards,
Jer
Posted by: Fred T---------------------
Quote:
[i] Now the system works more effecitnly as a whole and tyhe rider gets a better ride..
Regards,
Jer [/B]
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Cool! I can use a better ride! Thanks Jer that clears it up.
Posted by: RTL---------------------
Yes, thanks Jer!
FYI, I just dropped a RT tuner for poor customer service.. These guys acted like they were going out of their way to explain things to me. Heck, I was going to drop a grand into my bike with these guys and they acted like they were doing me the favors! Suspension may not be the weekend warriors life, but I would rather someone teach me than act like the job was a big top secret event!!!
Teach a man to fish and before long he will be teaching others the same!!
With that being said, Jer my forks and shocks will be in the mail this weekend. The point is you can treat people with respect, teach them, and you can still get their business. Suspension does not have to be this big secret and the average weekend warrior does not want to spend every free moment studying suspension metrics. That's why I pay professional tuners! And many people wonder why small dime-a-dozen RT shops get a bad rap...
Posted by: Jeff Howe---------------------
RT does not endorse midvalve technology. Thats about as easy a explanation as I can give you for that. They DO tell you that it creates compression damping(as if that is a bad thing). Actually one of the better things to come along lately when it comes down to it.
Posted by: EBOD---------------------
I also own a KDX. If I am riding on 1985 technology now, what year's technology will I be riding on after the fork re-valve?
--Eric
Posted by: marcusgunby---------------------
About 1996.
Posted by: EBOD---------------------
Would fork braces (which supposedly reduce fork flex) bring me any more up to date?
Is the rear suspension as outdated as the forks?
Thanks
Posted by: Fred T---------------------
Quote:
Originally posted by marcusgunby
About 1996.
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Marcus
Even if I add rebound dampening and midvalves you feel I've entered the year 1996? This is sort of like round two on my forks for Jeremy. I told him to give me the "complete treat" while doing service work and changing out to even stiffer springs so I can hammer those whoops. C'mon - I gotta be to at least 1997 
Posted by: HONDA65---------------------
RTL,
It is wrong to associate RT and poor customer service. If you got poor service from a small RT tuner, chances are you would have gotten it from them no matter who they were associated with. You need to remember that ANYONE can buy the Gold Valve kits and install them. Does that mean that they are qualified? Does that mean they are endorsed by RT? I am willing to bet that those who are actual Race Tech Centers won't give that kind of service, because they are the ones who have made a commitment to being in the suspension business, both in training(which I admit anyone with the money can take) and financially. And hopefully some one who has made that kind of a commitment has the skills and knowledge to do the work. Which again, I admit that is not always the case. Personally, I wish RT wouldn't sell their product to just anyone. I wish they would be like Jer and only offer their products through qualified outlets or directly through RT themselves, not through every distributor (thus dealer) in the country. Because when you get goofballs like you ran into, it gives a bad name to a good product.
Posted by: Jeff Howe---------------------
The only quaification that a RT Service Center meets over RT Dealer status is having storefront. Both individuals are required by RT to attend all 3 seminars they give. Just because a guy has store front doesn't mean he payed attention, and just because he don't doesn't mean he's a mindless twit.
But yeah, RT has created a neat empire. I am not a RT advocate, but I have a lot of respect for what Paul Thede has accomplished. In matters not concerning suspension specifically but business itself he is one smart guy.
Posted by: HONDA65---------------------
Not exactly. Another requirement is a financial investment IE; inventory, plus some basic rules to promote RT products. Plus there is contract to sign. And there are 3 levels of being an RTC. And you're right, just because someone takes the seminars, and even invests his money into the business, doesn't make him qualified. BUT, I would think/hope that someone who goes through all of that trouble would mechanically able and be commited to what he was doing, to seeing his business succeed, and thus doing those things nessacary to help insure that success. Thus good customer service, quality work, etc.
But like I said, one would hope.
As far as the quality of the RT products, they are by far the best of all of the suspension revalves I have tried over the years, and thats been alot. The only two major "brands" I haven't tried are MX-Tech and Enzo. Its quite possible that both of those are better systems (I'm sure everyone here will say they are
) but I can only relate what has worked for me in the 20+ years of racing. But my opinions are not etched in stone. I'm always up for trying something different, for learning something new. Thats how I came to my own conclusions about RT. Believe me,if I try something truely better, I won't hesitate use it.
Posted by: RTL---------------------
HONDA65
You are correct. It is wrong to associate these guys with the quality of RT products. I too have used RT products for years and love them! However, I think it would be safe to say that the RT franchising has allowed small, sometimes incompetent, shops to create a bad name for RT as a company. If I go to the RT web site and find my local RT shop, then in my mind they should provide the same customer service as a big shop out in Cali. In essence, they represent RT! TOP 10 RT Center displayed on the walls equalls RT in my mind. If you allow small shops to advertise as certified RT dealers then they had better be able to back it up. So, when all is said and done, this small local RT tuner does in fact represent RT and did in fact provide me crappy customer service. Do RT products stink? I think not. However, RT as a company may indeed have opportunities for improvement when it comes to franchise controll and customer services...
IMHO, of course.....
Posted by: marcusgunby---------------------
Fred T recent new innovations include(not in order)bladder forks 2000,bumper forks 1998ish,twinchambers 1994? the midvalve came in in 1995 on the KX i think.The present KTMs use a fairly simple fork-its main difference is a 14mm damper rod that displaces more fluid through the base valve so your fork wont be too different to that in terms of its makeup.
Posted by: HONDA65---------------------
RTL,
Can't argue. Its too bad that happened. Maybe you should call RT themselves and tell them.
I would.
Posted by: HONDA65---------------------
Marcusgunby,
Actually the new WP (2001 at least) does have a midvalve. However, it has so little pressure on the shims (none virtually) it might as well not even be there.
Posted by: marcusgunby---------------------
Honda 65 what i was trying to say was the KTM fork is similar to a 96KX fork apart from the 14mm damper rod-yes it does have a midvalve and has done since introduced in 2000.I was trying to say the KDX fork after mods isnt much different from a 2001 KTM fork-sorry for the lack of clarity.
Posted by: DEGBERT---------------------
If the active valve "float" or free bread deteremines at what speed the shim stack begins to influence control it would seem for supercross you would want very little or no "float", for MX you would want a little more float and for the woods you would want a lot of float. Is this a true statement or would the "float" stay the same in all cases and only the passive valveing change accourding to the application?:think
Posted by: marcusgunby---------------------
IMO its a good idea to alter float occording to application but i can see it would mean a infinite amount of variables for a tuner to work on.It must be necessary to choose maybe one setting for woods and another for mx/sx.Then work on the passive side.Ive found even with almost no float(like on a CR)its possible with a very soft passive stack to get a good compromise,having this very soft passive stack may lead to other problems though-testing carries on
Posted by: John Curea---------------------
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.
The RT design has to be basic enough for a guy(with a mechanic "ability") to watch a video, and revalve his forks. The simpler RT can make the process, the better chance the do it yourselfer will succeed. Taking the midvalve out of the equation, makes tuning easier, unfortunately, the baby just went with out with the bath water.
Take Care, John
Posted by: RTL---------------------
John, thanks for your insight.
Now, Fred T, Jer, John, I have a question for you. I have made the decesion to 'train' to become a weekend warriror suspension and motor tuner. I am building my dream KDX 200 and I am having tons of fun doing so.
Now that I am learning to fish, I was wondering if I should attempt my own suspension setup versus having Jer build me those 'works' bumpsticks. Could MX-Tech sell me the parts like RT and then consult me through a basic fork build. Kinda like with RT, new valves and springs without midvalves and rebound adjusters to make it simple? Or would I need tools that the average weekend warrior does not have? What do you guys think?
Thanks for your responses
Posted by: cp380sx---------------------
Race Tech treats me well!
Posted by: Fred T---------------------
so does that answer your question?
I do not have the:
1. Tools
2. Skills
3. Time
4. Patience
5. Confidence
to do this work myself. But I do like to ride!
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