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Pike 454 Air Pressure???

Hair TriggerHair Trigger Posts: 24
edited August 2010 in MTB workshop & tech
Hi People,

This has probably been discussed before but couldn't find anything that direcly related so, here goes...

I have a Rock Shox Pike, U-Turn, Dual Air 454 Fork and have fiddled with different pressures to obtain the correct sag etc. I weigh 200lbs, give or take and going by the manufacturers guidelines on the fork leg, I should be using 170psi in both positive and negative chambers but when I do this (wearing all my usual biking clobber, plus camel pak etc) I get about 7 to 10% sag (rather than the desired 20 to 25%) and the small bump response is very harsh. I've found that putting 135psi in the positive chamber and 145psi in the negative chamber sets the sag at the desired 20 to 25% sag and make the overall response from the forks very reactive and responsive, almost to the point of being soft. I have yet to bottom out the fork but have, of course, noticed that it dives further into the overall travel under braking and rough(ish) terrain in comparison to the manufacturer's suggested pressures for my weight, however, I also get a a slight sea-saw effect in conjunction with the rear shock at times.

My question is, have I moved too far away from the manufacturers suggested pressure guidelines so as to make the fork too soft for my weight and if so, should I compromise sag settings and up the pressures to say 145psi in the positive and 155psi in the negative chamber? (I've tried this and variations and it reduces the sag to around 15%)

I look forward to your replies and suggestions.

Tim

Posts

  • supersonicsupersonic Posts: 82,708 Lives Here
    The suggested pressures are nigh on useless - go on what feels right to you.

    Set sag: 15-20% gives a firmer ride, 20-25% is pretty standard, 25-30% a little softer.

    To combat brake dive use the compression damper adjuster.

    Also see FAQ on RS air forks - I would try to start 140psi in each chamber, see what sag that gives.
  • Cheers Supersonic - I will relax now in the knowledge that the suggested guidelines are pants! ;)

    Tim
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