Crank wobble/vibration when pedaling at speed..

surlysoul
surlysoul Posts: 17
edited October 2013 in Workshop
Hi All,

I'm getting to grips with my new self build road bike and have a slight niggle!

When pedaling down hard at speed I noticed a judder or vibration in my chainset. It seems smooth at all other times..

Any thoughts to what this might be.. I have a brand new sram rival chainset with GXP BB which all seems tight and has no play.. Could it be that I haven't faced my BB shell and it's not quite aligning my BB properly?

Cheers..

Comments

  • gethmetal
    gethmetal Posts: 208
    It could well be...
  • gethmetal
    gethmetal Posts: 208
    edited August 2010
    Whoops double post...
  • gethmetal
    gethmetal Posts: 208
    edited August 2010
    Whoops triple post. I hate my laptop :oops:
  • rake
    rake Posts: 3,204
    1+
  • rake
    rake Posts: 3,204
    +1
  • rake
    rake Posts: 3,204
    +1
  • topdude
    topdude Posts: 1,557
    Rubbish, nothing to do with facing the BB.
    The bearing cups are aligned by the threads inside the BB and just butt up to the outside faces. If the bearings were that far mis-aligned you would never get the axle through them.
    Could be the left crank is not butted up to the bearing giving some sideways play or something to do with the chain :?:
    He is not the messiah, he is a very naughty boy !!
  • gethmetal
    gethmetal Posts: 208
    So facing BB's is a complete waste of time. The threads will do the alignment.

    Right...
  • theruck242
    theruck242 Posts: 1
    i can't believe that this is the 10th web page describing the exact problem i have but there are none answers. what is wrong with you people? when in trouble you ask the community but you do not share the knowledge/experience once you solve it...
  • Monty Dog
    Monty Dog Posts: 20,614
    Either knackered bearings or incorrect installation.

    I've never been convinced for the need to face BBs - it's the threads that align the cups and there's no way you can distort the cups - if the cups do distort they're badly designed.
    Make mine an Italian, with Campagnolo on the side..
  • kajjal
    kajjal Posts: 3,380
    First check everything is done up tightly enough and aligned properly. This includes QR on the wheels, derailleurs and that the wheels are stable. A loose QR means the wheel starts moving more under heavy pressure. Check all bearings hubs, BB, pedals etc are not loose with play in them. Pretty much anything lose or rubbing like a poorly aligned front derailleur can cause noise and vibration.

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