Spring rates, I need em!

[Buttercup]

What is the spring rate for the 250R? I have an 04 crf450 and 250 and the suspension on my 450 is way softer. What is the difference in the springs? If i put 04 450 springs on my 250 (if i could) would it be softer?

[therapture]

2004 CRF250 stock spring rates are 5.3 rear and .45 fronts, the 450 stock uses 5.5 rear and .47 fronts.

So the stiffer springs for the 250F, are the same as the STOCK springs on the 450F.

To answer the question, if you put the stock 450 springs in your 250F, it will be STIFFER. At 200lbs I am using the stock 450F springs I had left over from a previous bike. Which are stiffer than the stock 250F springs. ?

EDIT: looks like you said 250 "R" 2-smoker...I don't know what rates those are stock, but they are softer than the 450F I can tell you that. The 450 weighs alot more. So using the 450 springs on the 2-smoke 250 will still be STIFFER than the stock 250 springs...

[Buttercup]

no, im a 4 strokes. Why is my 250 so stiff and my 450 so soft? is it valving then? I should probably run this over to the suspension forum.

[therapture]

The 250F is sprung a bit stiffer than your normal "125cc" class machine...

The 450F is alot heavier to start with, has alot more gyro effect from the engine too...and if your oil has not been changed periodically, any bike is going to be softer due to damping changes from viscosity breakdown.

To know where you are at, we need to know what sag settings you are able to get....are you familiar with this?

[Buttercup]

Ive got the rear spring pre-load backed all the way off on both bikes. The 250 has 3 1/2 inches of race sag and the 450 has 4 inches.

[therapture]

Ive got the rear spring pre-load backed all the way off on both bikes. The 250 has 3 1/2 inches of race sag and the 450 has 4 inches.

OK, now measure the bike sag with it sitting on the ground, no rider, with a full tank of gas. We need to know that measurement. That is what determines if you are using the correct spring rate. And what do you weigh?

[Buttercup]

Ill get the static sag tomorrow. I weigh about 160. Thanks for the help so far ?

[skipn8r]

no, im a 4 strokes. Why is my 250 so stiff and my 450 so soft? is it valving then? I should probably run this over to the suspension forum.

If by "stiff" you mean that the bike feels harsh while riding and transmits sharp impacts direclty to you rather than absorbing them, it's probably damping/valving related.

[Buttercup]

the problem is mainly the first half of the stroke. It doesnt settle into corners. The bike feels like it rides high, like it doesnt settle. I had the forks re-valved and it made a good difference through the braking bumps but the whols bike still feels a little stiff.

[Buttercup]

Static sag on my 250 is 1 3/8 inches. Is it sprung too stiff?

[therapture]

Static sag on my 250 is 1 3/8 inches. Is it sprung too stiff?

Yes. You want to get 100mm of rider sag and have from 15mm to 25mm (.59 inch to 1 inch) of free sag. At 1 3/8" (35mm) you are sprung too stiff, this would account for the "not settling" the front end into corners....

[therapture]

Ill get the static sag tomorrow. I weigh about 160. Thanks for the help so far ?

160lb is a bit light for the standard springs. I think a good setting would be to go one size softer on both fork and shock, say, a 5.1 or 5.0 rear and .42 fronts...the 250F is sprung a bit heavier than your average "125cc" class machine...really, a 180lb guy could probably get correct sag settings using the standard springs. At 20lbs lighter than that....you really need a softer spring at both ends.

[mikerides33]

a 180lb guy could probably get correct sag settings using the standard springs.

Just to reinforce what Rapture said. I am 180lb and have correct measurements using standard springs. ?

[Lackey-92]

Yes, the spring is too stiff. Idealy you should set the rider sag at 100mm (4") and have 17mm-30mm (.75"-1.25") free sag.

If you where to set you rider sag at 4" instead of 3.5" you would have even more free sag as it will require loosening the spring. It 's too stiff.

If your rider sag is correct and you have > 1.25" of free sag then the spring is too stiff.

If the rider sag is correct and you have < .75" of free sag then the spring is too soft.

[therapture]

Yes, the spring is too stiff. Idealy you should set the rider sag at 100mm (4") and have 17mm-30mm (.75"-1.25") free sag.

If you where to set you rider sag at 4" instead of 3.5" you would have even more free sag as it will require loosening the spring. It 's too stiff.

If your rider sag is correct and you have > 1.25" of free sag then the spring is too stiff.

If the rider sag is correct and you have < .75" of free sag then the spring is too soft.

For the record guys, this is the man that does my suspension...it's good ? and he knows what he is talking about.

Hey Don, did you get the check? Any word on the head?

[Buttercup]

hmm, looks like ill be looking into springs. Thanks guys