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Bottom bracket query

darrell1967darrell1967 Posts: 360
I’m building a trick Boardman Hybrid that’s going to use a Tiagra chainset.

I tried said chainset in the frame using a spare bottom bracket which is model number BB4700 so I bought another one off eBay. Stupidly I didn’t check the model number but it turns out to be a BB52. Apparently it’s for a Deore. Question is will my Tiagra work in it?

Cheers

Posts

  • masjermasjer Posts: 363
    Yes it'll work fine. They use a universal spindle size (24mm).
  • darrell1967darrell1967 Posts: 360
    masjer said:

    Yes it'll work fine. They use a universal spindle size (24mm).

    Excellent. I thought as much.
    Thanks.
  • darrell1967darrell1967 Posts: 360
    edited May 2020
    Learnt today that as masjer said, the spindles are both 24mm diameter but the plastic sleeves are different lengths.

    It seems that an MTB bottom bracket is 7-10mm wider than a road bike bracket.

    No dramas cos it was only a tenner.
  • darrell1967darrell1967 Posts: 360

  • masjermasjer Posts: 363
    edited May 2020
    You can use the shorter black plastic insert in the new bottom bracket or leave it out entirely.
  • lesfirthlesfirth Posts: 1,226
    edited May 2020
    Why do you not just swap the plastic spacer?
    Edit . Sorry i did not read the above post.
  • darrell1967darrell1967 Posts: 360
    edited May 2020
    Because I’m building 2 bikes

    The Specialized Tarmac will use Ultegra with the 4700 BB whereas the Boardman Hybrid is using a Tiagra groupset but I bought a 52 BB by mistake.

    I wondered if I could take the plastic sleeve out the equation because it doesn’t really seem to do anything.
  • You can run it without the plastic sleeve. It is really there as a form of added protection. Stops carp getting into the back of the bearings, but that doesn't happen too much in the real world.
    Its advisable but not essential.
  • darrell1967darrell1967 Posts: 360

    You can run it without the plastic sleeve. It is really there as a form of added protection. Stops carp getting into the back of the bearings, but that doesn't happen too much in the real world.
    Its advisable but not essential.

    Thanks for the advice on that. I did wonder if I could ditch the sleeve because on close inspection it doesn’t seem to do anything or be a structural part of the bb.
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