[Dh builder]

I bought a 10.5x3.5 fox dhx rc4 shock. The place I bought it from sent me a 3.25 stroke spring. The place I bought it from told me that it is a different size so that I will not bottom out the shock, after I asked them why they sent me a 3.25 when my shock is a 10.5x3.5.

I called Fox and they told me I should or maybe could or recommended to go longer than a 3.5 spring?? I think they said they sell 3.65 springs and that is what I should get. I never knew they even have 3.65 stroke springs.

OK, so I am confused here. What spring stroke should I get for my 10.5x3.5 DHX RC4 shock? Should I go with a 3.5 or a 3.65 or keep the 3.25? The weight is a non-issue as I know the weight that I want which is 400lbs.

 

[maxyedor]

Sounds like the shop is recommending you go into coil-bind to save the shock, stupid idea. I don't believe a 3.25" stroke will coil-bind at 3.5", as they usually allow some space between coils at full compression, however I'd trade it out anyway.

The shock has a rubber bumper on the shaft to prevent a harsh bottom-out, if you go into coil-bind you'll be bottoming out metal to metal, which is all kinds of bad for you, your bike, and handling.

Get a 3.5" stroke spring for a 3.5" stroke shock. Or do it the hard way, and measure the free length of the 3.25" spring, count the coils, and subtract the total of all the coils from the free length to find the amount the spring can actually compress and if it's more than 3.5"+your preload, it'll work.

 

[wood booger]

Fox marks their springs with actual "bind stroke", it will always be more than shock stroke. 3.65 for 3.5 stroke, 3.4(?) for 3.25 stroke, etc.
Other companies (like X Fusion) mark their springs based on shock stroke they are to be used with. 3.25 spring for 3.25 shock.
So kinda depends on the spring mfg.

But yeah, coil bind is bad. Better to be longer than shorter as the ladies say.

 

[Dogboy]

A 3.25 Fox spring is for a 3" stroke shock.

 

[yellowdogx]

Take a set of calipers and measure all the free space between the springs coils (in a straight line) if the sum of these numbers is greater than the stroke of your shock you should be good to go.

Easiest way to get the right size spring with the lowest weight (as your not buying a spring with extra length your not going to use).

I have heard that doing this will cause the spring to fail earlier as you are causing the spring to deflect more than a longer spring.