SRAM type 2

Sambuca
Sambuca Posts: 116
edited September 2013 in MTB buying advice
Been running a new sram type 2 rear mech with the clutch for the last week and have been feeling a clunk from the rear end. It turns out its the chain growth overpowering the clutch on the mech as the bike moves through its travel and it jumps forward just a little but causes a big clunk through the bike. Are people feeling this with the XTR shadow plus? It does it's job of keeping the chain tight but must be restricting the movement of the suspension ? Also feels horrible clunking every time you stand up and pedal or land a jump etc. Its on a whyte 146....

Comments

  • nicklouse
    nicklouse Posts: 50,675
    seems odd as that would imply the chain is being pulled the wrong way!

    i would not have though many have them yet due to the planned production has only just started.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
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  • Sambuca
    Sambuca Posts: 116
    It definitely is the mech because when you lock it forward with the button the clunking stops and the suspension is lovely and smooth again,
  • nicklouse
    nicklouse Posts: 50,675
    brain engage.... it is pulling the cage forward getting the clutch to slip. not much that can be done.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • The Rookie
    The Rookie Posts: 27,812
    Chain growth would see the mech move BACK, chain shortening move forward.....surely....are is the back and forward the suspension, I'm confused

    Sounds like the clutch is set too tight and then when the return spring/suspension movement finally overpowers it it goes with a bang perhaps? Not very familiar but can you adjust the preload on it?

    Hate the name clutch as it's really a damper (just a friction damper which is similar to a clutch - see the front of an old Bentley with friction dampers) but still that's just me!
    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.
  • Frodo1095
    Frodo1095 Posts: 252
    I haven't had any of these issues with the Shimano XTR shadow +
    2015 Ritchey Swiss Cross Disc
    2013 Santa Cruz Highball AL
  • fritzz11
    fritzz11 Posts: 40
    My xtr is quiet all the time, no noises at all, one of my favourite upgrades.
    2011 Cube Fritzz http://sdrv.ms/Z8xkDa
    2012 Zesty 714 http://sdrv.ms/YgJV4u
  • YeehaaMcgee
    YeehaaMcgee Posts: 5,740
    The Beginner wrote:
    Chain growth would see the mech move BACK, chain shortening move forward.....surely....are is the back and forward the suspension, I'm confused
    Semantics here...
    When referring to a full suss design, "chain growth" means, the amount a chain length must "grow" in order to accommodate the suspension action.
    So, a frame with a high degree of chain growth would see the mech move forwards as the suspension operates.
    My photos
  • Sambuca
    Sambuca Posts: 116
    Yes this is exactly what's happening so the problem will be the same if I switch to an XTR shadow plus although because of its different internal design may not clunk as it gets pulled forward.. Realise no one has alot of experience with the SRAM type 2 but it seems the XTR version isnt causing these issues for the users on here,
  • Sambuca
    Sambuca Posts: 116
    Someone suggest this but not sure it makes sense?

    "Run a chain device. The chain growth will be controlled by the roller as it moves and releases more chain. This allows the mech cage to maintain it's angle during chain growth"
  • YeehaaMcgee
    YeehaaMcgee Posts: 5,740
    No. Makes no sense whatsoever.
    My photos
  • nicklouse
    nicklouse Posts: 50,675
    LOL
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • supersonic
    supersonic Posts: 82,708
    Shimanos system has adjustable tension on the clutch, so it will move, slowly if needs be.

    You want it to move with a full susser. If you lock the mech out completely and you have sus with chain growth (like most), then the sus will not work!
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  • Chunkers1980
    Chunkers1980 Posts: 8,035
    It will, my weight on a heavy landing would be no match for a poxy clutch, something has to give or it'll bend something
  • hoots
    hoots Posts: 134
    I've been having exactly the same problem as the OP with X9 and X0 type 2 mechs (both on FS bikes), i.e. noticeable 'clunk' from mech when suspension compressed, as chain overcomes resistance of clutch mechanism. I'd got to the point where I'd given up with type 2's and was going to fit Shimano, so with nothing to loose (er..apart from some more money!), I thought I'd try a DIY fix on the type 2's.

    Just in case anyone is having similar problems with their type 2 mech, I thought I'd post the quick fix that I've found works. (apologies in advance for lack of photos and exact size of torx required)

    Lie bike on its side with drivetrain facing upwards. Prize off small shirt button sized plastic cap/cover off the clutch mechanism of rear mech - this reveals a threaded plug with torx type recess (circa 8 or 9mm size). I hadn't got the correct sized torx, so carefully removed it with the large allen key I use for pedals (8mm I think). The plug is thread locked in but is not torqued super tight, so with care, it's easy to remove with the allen key without damaging it. The base of the plug has an O-ring, so needs a little teasing out to pull the plug free (I used a drop of chain lube to ease things).

    Once the plug is out, it reveals the top of the clutch bearing. I put about 6 or 7 drops of ceramic chain lube on the bearing whilst moving the mech cage back and forth. Some of the lube disappeared down two small holes in what I think is a retaining ring, and the initial breakaway point of the clutch instantly improved and the movement of the cage is much smoother. Screw the plug back in and clip the cap on and you're good to go.

    TBH, I wasn't expecting much, but it worked!! I've tried both mechs on two rough rocky and bumpy rides and they've performed better than new - no knocking, the chains stayed on and the clutches still seem to prevent chain slap. I'm trying to convince myself that it's not just mental, but I'm sure the VPP suspension on the one bike seems to perform better now aswell.

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