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Bottom Brackets

MrJim007MrJim007 Posts: 64
edited July 2012 in Workshop
I have decided to up my fettling and having noticed some play in my bottom bracket decided to have a go myself. I have a 9-speed Tiagra chainset and the existing BB is of the Hollowtech 2 variety. I popped into my LBS and asked for a Hollowtech 2 BB and once home realised it was different to the one I took out. They appear to have given me one for a Mountain bike and my old one says Road on it, the threads are different lengths. Upon further investigation I have now realised there appears to be an endless amount of varieties of Hollowtech 2 BB's.
This will probably seem like a stupid question but do you match your BB to the chainset you have on your bike? I realise you have differing sized shells (68mm/70mm/73mm) but can you put any chainset you want into it and then you have to get the correct BB for that particular chainset.


  • Cleat EastwoodCleat Eastwood Posts: 7,508
    If you mean if you have a tiagra BB can you put an Ultegra crank in it, then yes - the cranks and BB's dont have be of the same model. I have dura ace bb and tiagra crank - oooh get me.
    The dissenter is every human being at those moments of his life when he resigns
    momentarily from the herd and thinks for himself.
  • MrJim007MrJim007 Posts: 64
    Yes, I am sort of getting at that. My old BB I took out says 'BC1.37x24 Road' on it yet I have seen a 105 BB on Ebay that says '36x24 Road' on it. Will this work with my Tiagra Chainset, what do these numbers mean? Also in the blurb it says 'Outboard bottom bracket bearing cups for use with 105 FC-5700 and FC-5703 HollowTech II chainsets'. So will it not work with any other Hollowtech II chainset?
  • topdudetopdude Posts: 1,557
    You need a 68mm road BB, either Tiagra or 105 or Ultegra. Just get a Tiagra one from CRC for £12 that will work fine, no need to pay more than that.
    He is not the messiah, he is a very naughty boy !!
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