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PDS revalve for new spring - Restackor weight scaling

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I'm trying to model enough of the rather busy internals of a PDS shock on a stack by stack basis to complement a fairly big jump in spring rates.

I'm 'just a wee bit' over my head. Anyone have some PDS tuning tip CONCEPTS that will allow me to cover both the velocity AND the position without actually test riding the damn bike?


As I'm sure you all know, there's not a huge pile of PDS function overview out there that goes to this level............😳

Also, Pri Rebound stack weight scale...how close do you have to get with the curve fits? And is several metric tons of damping a real thing...???


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Are you running a progressive spring?

Set the main stack for the primary spring rate, both compression and rebound. The secondary is only additional damping when the suspension compresses, in theory you could probably leave it alone. Especially if you use a straight rate spring. If you've changed from a straight to progressive spring, you'll need to set the secondary up to compensate for the secondary spring rate. Or if it has a progressive spring already, you'll need to compensate for any variation soft/hard on the new spring. Like if the new one is say 10% stiffer on the soft rate, but 20% stiffer on the stiff rate, you'll need to bump up the secondary rebound (as well as the primary), as it makes a difference only when the spring is compressed, and at least theoretically working in the higher rate area.

The PDS will need a fair bit of rebound, they run pretty stiff springs.

For a shock, 3m/s is plenty fast enough, they rarely see more than that. In fact, the rebound won't even see that much.

That's a terribly progressive curve, I'd be trying to flatten it out a fair bit.

The curves should be fairly close, at least within the clicker range, unless you're changing it for a reason.

Edited by DEATH_INC.
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Posted (edited)

It's a 500 EXC from 2014. A heavier guy wants to ADV it, and we've decided on 9.2Kg/mm, up from 7.3, so it's a fair jump.

Straight rate.

I worked my ass off to get that damn HS curve fit just because the dotted red line was projected there, never once thinking that ReStackor is just scaling what may be a bad stock curve! Thanks for that wake up call, and the advice. I may actually get this done if my computer doesn't keep erasing my work...it keeps crashing due to a probable mobo issue.

Edited by Keebler750
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