400ex ride height?

[trailrider894]

Hey guys, i am wondering, i have +2 A-arms and i am racing motorcross next year. I am wondering what my ride height should be in the front?

[PaRedneckRiders]

im thinking with 450r shock u should be right around 11-12in from the ground to the enter of the frame in the front.
If u ran yfz450 shocks it would drop it down to about 10in

[416racer]

It should be 1/4 to 1/2 inch higher than rear. I think for motorcross you'll want to be in the 6-8 inch range.
BTW where are you going to race mx at?

[dustin_j]

Get the rear of the quad set up (I recommend GT Thunder's linkage and a resprung/revalve). Then set the rear ride height (40-50%) by sag, and put the front 1/4" higher than the rear. All measurements with rider standing on the footpegs for consistency.

[trailrider894]

Originally posted by dustin_j
Then set the rear ride height (40-50%) by sag, and put the front 1/4" higher than the rear. All measurements with rider standing on the footpegs for consistency.

Can you explain this in a little better detail? It seems kinda confusing...

What does the GT Thunder Link do for me?

[trailrider894]

and could i get my shocks rebuilt by somebody else and get the gt thunder link? or would it be best to not do that?

[trailrider894]

Originally posted by 416racer
It should be 1/4 to 1/2 inch higher than rear. I think for motorcross you'll want to be in the 6-8 inch range.
BTW where are you going to race mx at?

I was going to do the ATV Amatuer National next year, but heard some rumors of them not doing it. So i just plan to hit up some random races then i guess... if not i will drive to different states or something... Its my last chance to race before i have to start work full time.

[dustin_j]

The linkage changes the progression rate of the rear suspension. Progression rate is the change in leverage ratio (wheel travel / shock travel) throughout the wheel travel. Stock Honda has too large of a progression rate (like 55%), hence the bucking. GT Thunder's linkage lowers the progression rate (around 30%, but I still need to measure mine to verify), which makes it ride smoother through the travel. It also lowers ride height, which helps stability in corners. This is the best modification I've done to my quad, my brother's quad, and my brother-in-law's quad.

There are other linkages and other theories for fixing the 400ex rear buck. I think a different linkage is the best solution, and GT Thunder's linkage uses a better progression rate than others I've seen (Elka). If you are going to use a different linkage, you will want to use a shock builder who frequently builds for those linkages. I'd use GT Thunder or M@ul Tech ATV, with a GT Thunder linkage. They will both make your front shocks work very well also. If you start using different companies front and rear, and/or ones not used to the linkage, you could end up with a quad that doesn't stay level and rides bad. I hope this helps your decision.