Rear shock - should it compress by hand?

apreading
apreading Posts: 4,535
edited August 2017 in MTB workshop & tech
Just bought a new Fox Float DPS shock from ebay - it apparently came off a new bike and it unused. Certainly looks that way.

Should I be able to compress it by hand, or see it compress/expand when I add/remove air from it? It doesnt budge even the slightest when I really push. Am I being silly and would only see it move if I put it on the bike and sit on it with my full body weight, or is there something wrong?

When I first connected the shock pump it was about 150 PSI. I let some out and still couldnt compress it by hand, let it out to about 75PSI and still the same so in the end I let all the air out and it still doesnt/hasnt moved even the slightest bit.

I had expected some, even if slight movement, particularly when I let some of the air out. And I thought it might move in/out when the air pressure was dropped to zero? I pumped it back up and in holds the pressure but just doesnt move.

Please feel free to call me stupid but I just want to check...! I dont have the bike with me at the moment so I cant mount it and check it.

Comments

  • cougie
    cougie Posts: 22,512
    Not got a FS but if you could put the force of a jump out in your hands I'd not be shaking hands with you.
  • apreading
    apreading Posts: 4,535
    cougie wrote:
    Not got a FS but if you could put the force of a jump out in your hands I'd not be shaking hands with you.

    But you can compress front forks by hand. And its not just jumps that compress the rear - as soon as you sit on it the sock sags - especially if you set a really low pressure, you can probably get 100% sag just through your weight at very low pressure.
  • moonshine
    moonshine Posts: 1,021
    No, you can't compress it by hand.
    Fit it to the bike and it will compress fine
  • JGTR
    JGTR Posts: 1,404
    moonshine wrote:
    No, you can't compress it by hand.
    Fit it to the bike and it will compress fine

    I would think it would compress with zero pressure?
  • The Rookie
    The Rookie Posts: 27,812
    With no air pressure you,should be able to compress it by hand, the best test is to remove the valve completely.

    I've found its pretty hard to move a shock by hand until pressures get down below about 30psi as they are used with high numerical linkage ratios and they are harder to get a grip on than forks.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.

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