Tightening of brakes effecting suspension stiffness

aaronw2
aaronw2 Posts: 8
edited June 2013 in MTB workshop & tech
Before posting here I have asked around in many shops but they have never heard of my problem and don't know how to fix it. My older bike a diamondback groove (2010) has a problem where the tightening of the brakes effects the stiffness of the suspension. I need the front brake to be tightened for the suspension to be loose enough to be classed as suspension still. If the front brake it not fully tightened the front shock goes completely stiff. Also when tightening my front brake the pads do rub a lot with the disk, but I can fix this myself.

Any advice or knowledge of this problem would be greatly appreciated.
Thanks -aaron

Comments

  • bails87
    bails87 Posts: 12,998
    What fork?
    What brakes? And/or what type? Disc/rim?

    And what do yuo mean by 'tightening' the brakes? What exactly are you doing?
    MTB/CX

    "As I said last time, it won't happen again."
  • aaronw2
    aaronw2 Posts: 8
    Not very knowledgeable about this bike,
    fork - GILA pro RST
    brake - Disk brake, from reading all I can tell you is that it is shimano v brake ( however it is disk) with quad qmd 5 pads.

    When tightening I am twisting the pad adjustor making it tighter.
  • supersonic
    supersonic Posts: 82,708
    I'd say that adjusting a brake pad to affect fork stiffness is impossible - but if it does happen, and you can sort the rubbing, why not just do that?
  • supersonic
    supersonic Posts: 82,708
    Also post some pictures of your set up.
  • The Rookie
    The Rookie Posts: 27,812
    Absent some weird reaction (interference of items not meant to be interfering with each other), it's just not possible for tweaking the pad adjuster to affect suspension stiffness.
    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.
  • aaronw2
    aaronw2 Posts: 8
    That is what every shop has said that it is impossible aswell. I will post a few pictures when I can, even with my tightening/adjusting brakes fix the suspension is still very still. It wont take in the impact of a 3ft drop at all.
    I may send my bike o evans suspension workshop and see if they can reset it or just buy a new fork altogether.
  • The Rookie
    The Rookie Posts: 27,812
    What do you mean by it won't take the impact of a 3foot drop?

    What forks? Presumably basic if you have cable discs?
    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.
  • cooldad
    cooldad Posts: 32,599
    What do you mean by it won't take the impact of a 3foot drop?

    What forks? Presumably basic if you have cable discs?
    aaronw2 wrote:
    fork - GILA pro RST
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools
  • aaronw2
    aaronw2 Posts: 8
    When doing small jumps or drops, about 3ft in height the forks stay stiff, there is no movement when the bike is landing at all. Even if I were to drop the bike onto only the forks they wouldn't absorb the impact at all.
  • supersonic
    supersonic Posts: 82,708
    But if you take the brake off they work?
  • Plyphon
    Plyphon Posts: 433
    Have you taken your bike into a shop and demonstrated the issue?

    That would be what I would do.
  • aaronw2
    aaronw2 Posts: 8
    If I take the brake off they go stiff again...
  • supersonic
    supersonic Posts: 82,708
  • thelonegroover
    thelonegroover Posts: 1,073
    A three foot drop is quite high. If you have your weight on the handle bars on a drop from that height and there’s no absorption, you will be in danger of breaking the frame. Never mind your wrists. Plus, you shouldn’t really be using the front brake in that situation.
    Planet X Kaffenback 2
    Giant Trance X2
    Genesis High Latitude 2x10
    Planet X n2a
    Genesis Core 20
  • The Rookie
    The Rookie Posts: 27,812
    I wouldn't be doing 3 foot drops on RST Gila's anyway.....

    As the bike weighs about 13-15Kg to the rider 70+kg the suspension responce when dropping the bike is irrelevant to how it will perform when ridden (which is when it is meant to work), how do you know there is no suspension movement when you land on the bike?
    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.
  • The Rookie
    The Rookie Posts: 27,812
    edited May 2013
    Duplicate post
    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.
  • aaronw2
    aaronw2 Posts: 8
    If the bike is still, you would expect to be able to push the fork down, even slightly. There is no movement even if I push down with two people the forks remain stiff. I have had them adjusted by the shop since the last post, still there is no movement.
  • thelonegroover
    thelonegroover Posts: 1,073
    Not locked out are they?
    Planet X Kaffenback 2
    Giant Trance X2
    Genesis High Latitude 2x10
    Planet X n2a
    Genesis Core 20
  • ilovedirt
    ilovedirt Posts: 5,798
    And how does that have anything to do with the brakes?...
    Production Privee Shan

    B'Twin Triban 5
  • supersonic
    supersonic Posts: 82,708
    I have seen this happen with V brakes, in a slightly different scenario - pull the brakes, it forces the legs apart slightly, then the fork works. But with a disc caliper, nay.

    This is why I want pics ;-)
  • Is the lockout mechanism functioning properly?
  • thelonegroover
    thelonegroover Posts: 1,073
    How many bike shops have checked the forks for you? And which shops, because I wouldn't want to take my bike to them!
    Planet X Kaffenback 2
    Giant Trance X2
    Genesis High Latitude 2x10
    Planet X n2a
    Genesis Core 20
  • benpinnick
    benpinnick Posts: 4,148
    You know that pad adjuster? Not on top of the fork leg by any chance?
    A Flock of Birds
    + some other bikes.
  • thelonegroover
    thelonegroover Posts: 1,073
    Not heard from the OP for a few days, is he OK?
    Planet X Kaffenback 2
    Giant Trance X2
    Genesis High Latitude 2x10
    Planet X n2a
    Genesis Core 20
  • aaronw2
    aaronw2 Posts: 8
    Sorry been getting it fixed.. I have no need for pics now, I sent the bike off they stripped down the forks and replaced the brakes and gears. The problem seems to be fixed or greatly improved. I plan to get some new forks anyway.
  • cooldad
    cooldad Posts: 32,599
    Kaching!
    I don't do smileys.

    There is no secret ingredient - Kung Fu Panda

    London Calling on Facebook

    Parktools