KDXRIDER.NET

2 weeks ago I took my KDX to a MX park for the day. I think I found out the hard way that the front suspension is set way too stiff for my weight, as every bump and turn and jump was slowly beating me up. I rode a friends YZ whose suspension was set for him (he weighs about the same as I do) and it was super smooth and controllable compared to my KDX, granted he has USD forks and I don't but it made me consider setting up my suspension. I went to racetech's website and they recommended .46 springs for my weight, 140 lbs without gear (every spring rate calculator gave me different results) and i currently have them in my bike. But I'm also using emulators and thicker fork oil, and the springs are pretty tight in there as the spacers are relatively large. I'm no suspension expert, so what do y'all recommend? Are the stock spring rates OK? Do I just have to use different spacers and that will solve the harshness?
I played with the clicker adjustments and they hardly did anything

What springs are in there? KDX forks and "too stiff" don't belong in the same sentence. I think the only way to make them too stiff would be way too much spring. There's almost no amount of setup you can do to the stockers to make them too stiff for an MX track. Are you sure they aren't bottoming out constantly, or riding up in the top of the stroke all the time?

+1

Haha yeah they were beating me up at the track when I went. I'm pretty sure they weren't bottoming out. My current setup is .46 Eibach springs, Castrol ATF dextron 6 for fork oil, measured at I think 125 or 130mm from the top, fork emulators set at half way screwed in, and the big spacers made me cram the springs in. Im wondering of shorter spacers and/or the stock springs would remedy this problem

That sounds like a super stiff setup for someone like wibbens. At 140 I'd say make new preloads at about 10mm of spring compression when the caps are on and go to about 150mm for the oil level. I'd try fredettes rates and go up one or 2 stiffnesses for mx stuff.

IMO you just went way to stiff.

I know nothing about emulators or their set up but I'd like to try them...

.46 is way too stiff for your weight. I weigh 155, have .38 in my KDX and it's perfect for me. My MX bike has .40 and it's borderline stiff for my preferences.

How can i tell what rate the springs are? I re-installed the springs that used to be in there before the .46's. I know that they are Progressives and that they are far more smoother than the .46 Eibachs, but not sloppy like the stock springs

That's a mystical question, I'm not sure there is a way to tell....

Mathematically, Hooke's law states that

F=-k*x

where
x is the displacement of the spring's end from its equilibrium position (a distance, in SI units: meters);
F is the restoring force exerted by the spring on that end (in SI units: N or kg·m·s-2); and
k is a constant called the rate or spring constant (in SI units: N·m-1 or kg·s-2).


the real mythical question is how to measure the force exerted by the spring when you compress it.

I may be interested in your .46 springs if you think you might want to sell them. I am running .40 XR springs which have been great the last couple of years but, well.... I've gotton fat.

haha yeah I'll let you know if I intend on selling them or not. I have an E-series KDX, will they fit your bike?

Yeah, i believe the springs should work for both E and H series.