Crankset/BB Compatiblity

chatlow
chatlow Posts: 850
edited October 2016 in Workshop
Looking for some advice on new crankset.

I have a 2015 Cube Agree GTC pro with 105 5750 and per many sites, the spec shows it has:

Shimano 105 FC-5750, Hollowtech II, 50x34T, 170mm (50/53cm), PressFit SM-BB71-41.

First of all, I always thought you couldn't have Hollowtech II with a press-fit BB setup?

I am wanting to replace the 105 crankset with Tiagra 4700 53/36 which uses Hollowtech II. Would there be any problems with this or will I need a new BB as well?

Thanks in advance

Comments

  • trailflow
    trailflow Posts: 1,311
    Both the 5750 and 4700 cranksets use a 24m spindle diameter so it's a straight swap. No change to the bottom bracket needed.

    You cannot use a Shimano crankset in BB30/BB30A/BB386 EVO without buying aftermarket adapters. Shimano only make pressfit bb's for BB86,BB71,BB92
  • chatlow
    chatlow Posts: 850
    trailflow wrote:
    Both the 5750 and 4700 cranksets use a 24m spindle diameter so it's a straight swap. No change to the bottom bracket needed.

    You cannot use a Shimano crankset in BB30/BB30A/BB386 EVO without buying aftermarket adapters. Shimano only make pressfit bb's for BB86,BB71,BB92

    Great, thanks. So that also answers my next question about my 2nd bike using BB30. If wanting same Tiagra 4700 then I will either need an adaptor or new BB to fit this.
  • trailflow
    trailflow Posts: 1,311
    Yes, either adapters like Wheels-Manufacturing BB30 to 24mm adapters that slide into the existing BB30 bearings. This is the cheapest option and is easy to install by hand. And makes it easy to switch back if needed.

    or install a full conversion sleeve like a Praxis converter. This is more expensive and more work that involves removing the existing BB30 bearings.

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