liam asked in SportsCycling · 2 months ago

Can someone explain cranksets to me?

I know the bottom bracket on my bike is a BB-UN55 73 x 122mm square taper. Are all square taper the same measurements?

2 Answers

  • David
    Lv 6
    2 months ago

    So is it cranksets or square taper you’re asking about?

    The taper itself is NOT all the same. Campagnolo uses one, the rest of the gang use another.

    Square taper BBs come in different lengths, usually between 113-122 mm and need to match the crankset. And the bike. Otherwise the chainline goes off and you risk messing up front shifting and/or have clearance issues.

    Cranks can have different crank arm lengths.

    1, 2, 3-rings.

    Riveted or bolted.

    Bolted come in 4- or 5-arm.

    And different bolt circle diameters.

    Cranks can have different Q-factors, ”width” between the pedals.

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  • 2 months ago

    Cranksets & bottom brackets are two different things.  A crankset is the front gears on a bike.  Could be a single, double or triple crankset.  And no...all  square taper B/B's are not the same.    There's seven of 'em all found on Amazon with the same BB-UN55 prefix.   


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