right on, dr jlm, with another clear, concise, correct description!

but i had assumed that the "short circuiting" of the spring length/rate would be "smooth" if, indeed, the pitch varies constantly over the length. i've seen one particular brand that looked like it had a constant pitch series of a couple of coils and another group of constant, but different pitch coils. i could see how it would clank the way you describe, but i can't picture a truly constantly varying pitch clanking.

thanks, any further insights are appreciated.

(i have the eibachs, which look to be constantly changing pitch. i haven't clanked them, but i don't corner nearly as hard as others on this forum and drive only on the street. plus, there is a tygon tube wrapped around the tighter pitch coils, but i doubt this will last.)

 

These are from the testing we have done here, using the spring tester from 3R Racing, which is very accurately calibrated.


Stock will depend on which set up you have - ie sunroof, headlights, Sport +, etc., but tend to be around 225 front and rear.

H-Sport uses a progressive rate, and they are 190 front and 320 rear once you are into the compressed range. Per inch of compression, the rate will change, which is what you are measuring - the rate is in pounds of force required to move the spring one inch.

H&R springs are also progressive, but do not split the rate front to rear. They are 280 front and rear in the compressed range.

Eibach are similar, though softer than the H&R at 250.

I haven't had the M7 springs in my hands, so I don't know of the rates for those.

I believe those are the only units I have the numbers for - let me know if you were curious on any other set ups. The Leda coilovers use any number of rates, depending on the car, but the most common are 250 front 350 rear for the street, and 350 front 500 rear for full race.

Hope that helps!

Randy

 

I've looked into H&R Coilovers and emailed them about the rates. The reply I got stated that the standard H&R coilover kit had rates of 465F and 235R, and the RSS kit had rates of 545F and 405R. Just FYI.

Randy, Leda uses linear rate springs with their coilovers correct?

Also, how do you think a GC kit sounds with rates of 325F 375R mated with Koni Yellows and a H-sport Comp rear bar? Comfort really isn't my biggest issue, and I do autocross the car at every opportunity and am starting to do some track events with it as well. Thoughts?

 

Isnt that why there are "barrel" types springs in order to eliminate coil binding?

 

"

Thanks for the info on th H&R coilovers. When I tested those, I hadn't found the spring tester that was accurate at that point.

Leda springs are 2 1/4, so you could use Hypercoil, Eibach, H&R, etc. The fronts I use we had designed for the MINI, and I'm not sure who is using those other than Webb Motorsports, but they are made by Leda, and are barrel springs to avoid the coil binding issues we were having with standard springs. They are linear rates.

The Koni yellows with a GC kit would be a good way to go, they just require you to design them yourself. I wouldn't go that stiff in the front, due to the harmonics of the chassis you might get an undesirable oscillation with that stiff a front and that soft a rear (even though the rear rate is stiffer, I'm talking about the split). Use a 275 front with a 350 rear. That should keep you where you want to be with regard to oscillations in rebound and give you the right dynamics for the balance (neutral). The only issue you may have is coil binding with the right height spring. We found that with the Leda and H&R kits. To get the right ride height, the spring needed to be 7", but with the rate we were using, there was an issue with the number and size of the coils, and we had bind before bump stop. If you stiffen the rate, the coils are either too many or too thick, and you throw off the balance. If you soften the rate, there isn't enough to keep the shock from compressing. That's why we ended up making a custom spring for the front.

Let me know if I can help - I'd be happy to.

Randy

 

I still think this would be an awesome solution... I noticed that someone in Germany is using them on their race car, or at least it looks that way - you can see what looks like the GC coilovers in this link...

http://www.hubertus.net/mymini/track...s/page_33.html

Also, note the brake cooling duct... trick!

 

"If you stiffen the rate, the coils are either too many or too thick...

stiffening the rate would require either fewer coils (less overall wire length) or thicker wire.

 

Has anyone tried these yet?

(bump)

 

You can get wirewraps at RadioShack and wrap your top coils. That'll
rid the chattering. :smile:

 

I was very interested in these back a few months ago, and when I called and spoke with a few people over at Ground Control I was informed that they're not yet ready for sale. They claimed they may be ready in March or so... but who knows. I ended up just getting H-sport springs with my Konis that I'm pleased with. Give GC a call, they're pretty helpful over the phone but damn near unresponsive through emails etc.

 

i second all of this exactly. i was interested in these back in late 2002 i spoke with cg at length by phone. they were very helpful and informative. i volunteered my mcs as a guinea pig when they were ready, but i never heard back.