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Bottom Bracket - play

Daz555Daz555 Posts: 3,976
edited February 2018 in Workshop
A few weeks ago whilst riding home on my 2014 Boardman Hybrid Comp my left hand crank arm started to loosen - I had no tools with me so rode gently hoping to make it home. Well I didn't - it fell off.

I have now retightened it and thought everything was ok. However today I notice that whilst it is fully tight, I am able to "knock" the crank/chainset from side to side by a few mm.

So I'm thinking that when the crank arm fell off I perhaps lost a spacer or two in the process? Can anyone confirm if this sounds about right? It is (I think) a BB-6000 FSA bottom bracket.
You only need two tools: WD40 and Duck Tape.
If it doesn't move and should, use the WD40.
If it shouldn't move and does, use the tape.

Posts

  • chris_basschris_bass Posts: 4,913
    the spacers are usually between the bottom bracket and the frame so it is unlikely.

    If you have a triple there is sometimes a kind of washer between the left crank and the bottom bracket (or at least there was on a specialized I had a few years back).

    have you tightened the plastic crank bolt as far as it will go?
    www.conjunctivitis.com - a site for sore eyes
  • Monty DogMonty Dog Posts: 20,614
    Is the play due to the crank rocking on the BB spindle or the spindle moving in the BB shell? If you've ridden with the crank loose on the BB spindle, then it can deform the splines in the soft alloy crank and no amount of tightening can remove it. Might be worth popping into your LBS for a proper diagnosis. You might be able to find a suitable replacement crank.
    Make mine an Italian, with Campagnolo on the side..
  • arthur_scrimshawarthur_scrimshaw Posts: 2,596
    I don't know but Boardman favoured BB30 bottom brackets, if so it's possible you lost the wavy washers and or some spacers when the NDS crank came off? These are used to take up side to side play in the assembly.
  • svettysvetty Posts: 1,904
    Daz555 wrote:
    I had no tools with me so rode gently hoping to make it home. Well I didn't - it fell off.

    There's your problem ;)

    Although to be fair many multi-tools won't have an Allen key large enough for large chainset bolts - I assume yours needs an 8mm? For Shimano chainsets though, crank clamp bolts are tightened with a 5mm Allen key which most multi-tools have. A handy multitool will get you home more times than not
    FFS! Harden up and grow a pair :D
  • Daz555Daz555 Posts: 3,976
    Re the splines - no they are fine. The issue is the crank spindle being able to move left and right by a few mm if you give it a kick even when crank arm is fully tight - I only noticed this when I was seeing chain rub against the front shifter despite knowing I had it set up correctly.

    Cheers for responses. As it is relatively new I'm going to have to just rock up to Halfords and ask them to sort - I just wanted to be armed with some info before I went there - I'm handy with bikes but don't trust Halfords and this is a new type of crank/bb for me.

    Wavy washers - yes I think there might be something in that. Hopefully that just dropped off when the crank arm dropped off. I'm going to get Halfords to show me a shop bike so I know what's up.
    You only need two tools: WD40 and Duck Tape.
    If it doesn't move and should, use the WD40.
    If it shouldn't move and does, use the tape.
  • veronese68veronese68 Posts: 25,950 Lives Here
    Daz555 wrote:
    Cranks move in a direction they shouldn't.
    Can I direct you to your sig? :wink:
    Although they are supposed to move, so should you use tape? You're going to need magic tape.
  • jgsijgsi Posts: 5,038
    There are a number of modern day BB standards.
    But
    get yourself one of these and fit it, if you are correct with your BB-6000 diagnosis.
    http://www.chainreactioncycles.com/fsa- ... lsrc=aw.ds
    Cuvettes_FSA_Meg_4e4d06447fe04_945x945.jpg
  • Monty DogMonty Dog Posts: 20,614
    If your BB is FSA BB-6000/MegaExo then its likely to be a Gossamer alloy crank or similar - have you got one of these for the non-drive crank?
    https://www.rosebikes.co.uk/article/fsa-crank-fixing-bolt-for-gossamer-mega-exo/aid:197327
    This is needed to take-up adjust bearing end-play before tightening the pinch bolts on the non-drive arm
    Make mine an Italian, with Campagnolo on the side..
  • A photo would help....

    If it is a BB30 FSA Gossamer crank, there were issues with them coming loose (despite being tightened to the corect torque). You can follow FSA's instructions for installing and tightening. Not sure why you have lateral movement - sounds like a missing washer...
    All the gear, but no idea...
  • Daz555Daz555 Posts: 3,976
    Update - now confirmed 100% to be a missing wave washer - after crank arm fell off I did not notice it was missing at the time. New one on its way.
    You only need two tools: WD40 and Duck Tape.
    If it doesn't move and should, use the WD40.
    If it shouldn't move and does, use the tape.
  • I had the exact same issue today, left hand crank came off on a fast downhill section and I thought at first my foot had slipped out of the pedal till I looked down and saw that the crank was attached to my shoe and not the bike! I have the same issue now too, lateral movement by a few mm in the bottom bracket spindle. Looks like I have also lost that washer so need to track something down also.
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