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Old May 10th, 2004, 00:30
RobertF RobertF is offline
NAXJA Forum User
Join Date: Apr 2003
Location: Santa Barbara
Posts: 361
Re: Pre-runner type suspension stuff

To shed a little light on gas pressure in a rebuildable, revalvable, reservoir shock.
You are not going to make the shock significantly stiffer or softer with a pressure change.
The pressure is exerted only on the cross section of the shock shaft.
Do the math, a 100psi increase on a 14mm shaft shock, an area less than a quarter square inch, is about 24psi.
Not really going to make the shock stiffer.
What is extremely important about the gas pressure is how it works on the oil.
The force the gas puts on the oil must exceed the damping force or the oil will cavitate going through the valving, the shock will fade, and your rig will turn into a flying pogo stick.
A stiffer valved shock requires higher gas pressure than a softer valved one to combat this.
Using unnecessarly high gas pressure will increase seal wear and shock stiction, so a manufacture recommends the pressure accordingly.
This is why Richard's rock crawling shocks use a lower pressure than Marcus's pre-runner shocks.
Raising the pressure in a softly valved shock will not make it stiffer and is unnecassary untill it is re-valved stiffer.
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