Worn XT crankset splines – Will it keep coming loose?

Viewing 11 posts - 41 through 51 (of 51 total)
  • Worn XT crankset splines – Will it keep coming loose?
  • Aye, it’s pointless Tracry, putting forward your experience of a fix that actually works when someone clearly knows better. I’ve worked in Engineering in a few forms for 26 years now, and I find myself quite surprised on a regular basis by things that just shouldn’t work, but they do.

    It’s only now at 43 that I’m actually studying the theory behind it all!.

    Here’s something to try. Do your little plastic cap up finger-tight to preload the bearing, fit NDS crank, torque to recommended setting, and then try and undo that finger-tight cap.

    Then tell me it’s not taking any load. 🙂

    hols2
    Member

    Tracey, its no good telling people that as a solution it works in practice, they ‘know’ that in theory it doesn’t work.

    So, do you guarantee that it won’t come loose again? I’m not saying it isn’t a useful bodge, but you have absolutely no way of knowing how long it will last because you don’t know how much the splines have been damaged, or how heavy the riders are, etc. It might last for years in one case where the splines aren’t badly damaged and the rider isn’t a heavyweight and it might last a few minutes in another case where the splines are badly damaged and the rider is much heavier.

    So, to answer the OP’s question as to whether it will keep coming loose, nobody knows. It’s probably worth trying, but just because it worked in one case doesn’t mean it will work in another. If you want a guarantee that it won’t fail, you need to replace the crank arm. If you don’t mind taking the risk, try the bodge and see how long it lasts.

    Premier Icon Tracey
    Subscriber

    In practice it worked for me and in theory it shouldn’t have. Others have said its worked for them or people they know. It may or may not work for the OP. You cant guarantee the new crank arm wont fail. We have damaged another XT crank beyond repair on a rock strike but did wait at the pub whilst it was pushed back.
    I wont fall foul of it again as most of the bikes are on X0 and when we go away in the camper, holidays or competing, have enough spares to build a bike except a frame. And have a spare bike just in case.

    We have bodged a few things in the 30 odd years of mountain biking, some worked some didn’t. I think the best was at the top of the Brazilian in Switzerland. We had done the hike a bike up the back and just set off on the down when the little rubber grommet on the top of Abigales Hayes 9 rear brake lever popped out. We bodged an allen key held in with tyre cement and duck tape to get her down to the valley bottom. It worked but it shouldn’t have.

    Hope it all works for the OP and is saves a bit of cash.

    Im going to leave it, my excuse is been a girl.

    hols2
    Member

    It may or may not work for the OP.

    Exactly. So the answer to “Will it keep coming loose?” is “Nobody knows because it’s impossible to know”.

    nickjb
    Member

    Funnily enough, exactly the same answer if you fit a new crank

    Premier Icon Akers
    Subscriber

    Thank you everyone for your responses, I had no idea it would spark so much debate!

    To be honest I was pretty much resigned to buying a new crank, but thought it was worth an ask before buying.
    An alloy cap has been purchased and installed. I loosened the pinch bolts for installation and could immediately feel the lateral play on the NDS arm, however as soon as I screwed the cap in place the arm would no longer wobble. With the pinch bolts retightened to the instructed 12nm it feels completely stable.

    I’m off out on a 30km loop on Saturday, so if the problem remains it will become evident.

    Thanks again.

    Best of luck mate.

    hols2
    Member

    Funnily enough, exactly the same answer if you fit a new crank

    If a shop charged you to fit a new crankset and it came loose, you would expect it to be repaired under warranty. No mechanic with any sense would offer any guarantee that a bodged repair to a damaged crankarm would last 5 minutes. Very different answer.

    Im going to leave it, my excuse is been a girl.

    Tracey, you’re one of the few folk I’d happily let work on my bike! 🙂

    Premier Icon Jon Taylor
    Subscriber

    Folk have been getting very het up in here and I don’t think there’s been any real disagreement. Just some folk saying “you’re not supposed to expect it to do X” and others saying “yes, but it can do X” 🙂

    Here’s something to try. Do your little plastic cap up finger-tight to preload the bearing, fit NDS crank, torque to recommended setting, and then try and undo that finger-tight cap.

    Then tell me it’s not taking any load

    It’s being pinched by the pinch bolts, which are squeezing the tube of the axle. I always, without fail, try and undo the torque cap before releasing the pinch bolts, ’cause I’m a numpty.

    I’m going to leave it

    I don;t think there’s any shame in removing oneself from a thread when it’s getting a bit repetitive 😉

    And good luck OP, if you keep everything nipped up it’ll hold on for quite a while.

Viewing 11 posts - 41 through 51 (of 51 total)

You must be logged in to reply to this topic.