Rockshox Revelation Positive Air problem?

shin0r
shin0r Posts: 555
edited January 2008 in MTB workshop & tech
Hi all - I have a set of Revelation 426 dual airs (130mm) - After a ride yesterday I noticed that they definitely weren't sitting at 130mm. They seem to be sagging even when I'm not on the bike. I'm guessing I need to add some air to the positive chamber (I'm looking through the manual now), but I'd like to get some expert opinions!

Here's a pic to explain what I mean - I've not measured but this doesn't look like 130mm to me.

bikesag.jpg

Comments

  • dave_hill
    dave_hill Posts: 3,877
    You need to check pressure in both the positive AND negative chambers.

    Drop the pressure right off in the negative chamber to start with. Set the sag using the positive spring, then pressurise the negative chamber to equal or slightly higher than the positive.

    As an example - I set the positive chamber on my Pikes to 150psi and the negative to 155 - 160psi. This is just enough to pull the forks slightly in to the travel and stop them from topping out.

    If in doubt READ THE INSTRUCTIONS. There's easy to follow step by step instructions on how to do it there.
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  • Splasher
    Splasher Posts: 1,528
    No it's not and yes you do need to add air. If that doesn't bring them back up, there's a fault.
    "Internet Forums - an amazing world where outright falsehoods become cyber-facts with a few witty key taps and a carefully placed emoticon."
  • nicklouse
    nicklouse Posts: 50,673
    Ok just a daft question. the 426 dual air can also come with a U-turn? which is yours?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • shin0r
    shin0r Posts: 555
    Hi Nicklouse - I can confirm this isn't the U-Turn version.

    I'm not quite *that* stupid :lol:
  • nicklouse
    nicklouse Posts: 50,673
    has the bike been stored up sidedown recently?

    Ok let all the air out and start again as suggested above.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • shin0r
    shin0r Posts: 555
    Thanks for the responses guys, I ended up removing all the air from both negative and postive and set 150psi in each - I'm nearly 14 stone and this give me about 15% sag.

    Some oil came out of the bottom schrader valve when I let the air out - not much, probably a teaspoonful - anything to worry about?

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