I have had these Dual air Revs since 2007. They used to work brilliantly with excellent small bump sensitivity. Over time they seemed to get slower, handling big bumps fine but losing responsiveness to smaller bumps. I recently changed the oil to see if that would help but they are still the same. Is this a symptom of needing to renew seals or something?
To clarify, this is not stiction, they freely move, its more like they have loads of compression damping or something.
Too much oil?
Would too much oil just limit travel and not affect the travel you get? They still have full travel fwiw.
Negative air chamber (The bottom one) leaking slowly pver time?
The imbalance of pressure (more psi in top than bottom) would create a setup like this
Having the pressures equal gives the best balance of suppleness but doesn't dive under braking/steep stuff too much for me
Haing more psi in the negative preloads the positve so it goes into the travel a little, making it very supple on small stuff, but dives a lot under braking/on steep stuff/harsh bumps etc ..
If you playing with the pressures, make sure you set the top (positive) chamber first. The negative (bottom) chamber is a lot smaller so setting this first, then putting loads in the top cuases the pressure in the small negative one to ramp up far too much
debris blocking the compression circuit?
atm the chambers are equal in pressure, the problem does feel more like its casued by damping but I'll double check that later. Possibly what science officer says.. how would I check that?
What brand and weight of oil did you use in the damper?
Without any air in the chambers, are they freely moving throughout the entire stroke?
It's the 5WT version of this: http://www.chainreactioncycles.com/Models.aspx?ModelID=112
Yes full movement through the travel with no air.
Have you ever stripped and re-lubed the air chamber?
I lubed the o ring at the bottom, is there something more you can do?
Did you strip it down like this...
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Yes that's the guide I followed, excepting that I didn't renew any seals.
Tried them this morning with more positive air in and they are no better 🙁
More positive will make them less plush on the little stuff.
I mean negative :P. typo
I think then you may be getting into the 'send to TF' (or ask him) territory!
Nooooo! That's a pretty expensive option 🙁
Maybe I'll try checking out the compression cartridge...
This may sound stupid, but i always start with the most obvious possibility...
Does the fork have a rebound adjustment? Has it been knocked to a higher setting accidentally?
Nah Ive set both the rebound and compression damping to minimum. It does feel like the compression is set too high tho, even on minimum.
Does the compression damping make it slower if you turn it up or does it stay the same. If it stays the same it may be a broken bit inside.
It does increase the damping yes, but only from hard to harder!
take out the compression damper and clean it with an air duster, then treat it to some fresh oil.
FYI That 5wt Stendec is what I use in my Pike forks, and it is a bit slower that the standard oil (nothing like what you describe though)