I'm posting this again, because my server became unavailable afer posting, and I didn't see this in the forum. My apologies if it's there.


Ok here goes, I'm sure someone will have an answer to this.
The question surrounds coilover springs used in a quad, either 250R or lt250.

The first question is does anyone have an idea what spring rate the stock springs front and back have? I think the rear is a 10" spring with 9 active coils, but have no idea what the spring rate is from the factory. Surprisingly the motorcycle pro's around here haven't been able to help me on this. They say I could bring mine in to measure them, but that wouldn't tell me what the stock spring rate is supposed to be.

Second question: What effect, if any, does the cantilever or pro-link type suspension on either the trx 250r honda, or lt250 have on the amount of spring rate necessary? I understand straight line spring rate like in a car application, but using a lever action may make the spring rate increase?

Also the angle seems to affect the spring weight required, doubling the required spring rate at a 45 degree angle as compared to verticle.

Assuming a 175 pound driver on a trx, what spring rate(s) front and rear would be required?

Here's what I know about springs. You place 200 lbs on the spring sitting upright on a table. The weight moves the top of the spring down 1 inch. So your spring rate is 200 lbs per inch. Each one of the ten coils has shrunk 1/10 of an inch.

A 200 lbs per inch spring rate will hold 100 lbs at a half inch, 200 lbs at one inch, and four hundred pounds at 2 inches, 600 at 3" etc.

However using this ratio, it seems strange that a quad and rider can put enough weight on the spring to fully compress it, unless the spring rate is a lot less than 100?

Anyway I hope someone has experience in this area. Thanks

 

Goto Race Tech's website, there you will be able to plug in all your information, then it will tell you what the stock spring rates are (ex: 5.0, 5.5, etc), and it will also tell you what different spring rates are available. They also seel there "gold" kits to rebuild your rear shock, or have it done. Race Tech is down in california, how far from you I am not sure. Here is their web address.... http://www.racetech.com

 

Thanks!