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Progressive Suspension Fork Springs

Posted: 03:21 pm Jan 15 2010
by exbee
I finally found a shop that has a set of springs for my 93 KDX 250 but they are progressive rate springs. Does anyone have any experience with these in a KDX? I would assume that any aftermarket spring is better than stock. The owner tells me they are 34-41 pound progressive rate springs. I'm not sure how that relates to the kg/mm rating of other springs. I know my stock springs are straight-rate, how will the progressive rate act differently? Any advice would be appreciated.

Posted: 03:38 pm Jan 15 2010
by Indawoods
Softer at the top... harder on the bottom.

Could work out real nice....

Posted: 06:55 pm Jan 15 2010
by IdahoCharley
They sound real stiff to me. I believe the KDX springs are somewhere in the 21-23 lb range at least for the KDX 200/220 machines.

Posted: 07:17 pm Jan 15 2010
by Mr. Wibbens
I thought stock kdx200 was around 33?

I'm +260 lbs and I'm running .46's on my 200

Posted: 07:27 pm Jan 15 2010
by Julien D
33 kg yes, and yours are 46 kg. Not quite sure how that relates to lbs, or if the OP was given the right information from the vendor to begin with. I'd bet they are 34 - 41 kg, as that would make much more sense since 1 kg is about 2.2 lbs. If those springs are 34 - 41 lbs progressive, that'd be something like 75 - 90 kg??? Unless you're a REALLY REALLY big guy, I'd say that's way too stiff. I've never seen springs rated in lbs/in so I'm not sure if I'm way off base here.

Posted: 08:33 pm Jan 15 2010
by skythrasher
15.4-18.6 Kg = 34-41 lbs I think you may have converted the wrong way.

Posted: 08:52 pm Jan 15 2010
by Mr. Wibbens
found this on wiki

1 kg = 2.2 lbs
so 33 kg = 72.6 lbs

Posted: 08:55 pm Jan 15 2010
by Mr. Wibbens
Springs on my Vstrom are 1.0 kg

Posted: 11:27 pm Jan 15 2010
by exbee
Yeah, maybe the shop owner is confused. 0.34kg/mm-0.41kg.mm sounds much more reasonable. 0.34 is the stock spring rate if I'm not mistaken so the progressive springs must start at the stock rate and progress to 0.41 in the stiff part of the stroke? Does that sound right?

Posted: 06:48 am Jan 16 2010
by Julien D
That would sound right, yeah. And if that is the case, I'd probably like those springs ;)