Bottom Bracket replacement / compatibility

MJS996
MJS996 Posts: 20
edited December 2016 in Workshop
Hi Guys,

I have an aluminium Giant Defy from around 2010 which I use as a winter bike now. It was a low spec model, with an old square taper BB.

A couple of years back I upgraded to a 105 groupset, and my local bike shop fitted a suitable BB.

Now I have clicking noise when I pedal, so I think maybe the BB is on its way out. From the markings it is a cheap MTB model BB51, and the reviews online are less than glowing, either for the BB51 or the replacement BB52.

So, question is - what can I replace it with? (If I can't trace the noises elsewhere). Is the width of threaded BBs standard? Would the BB R60 go in - it is sold as 105 5800 which matches my groupset, but will it fit in the frame?

Thanks
Martin

Comments

  • All Hollowtech 2 BB are the same... I don't think the BB R 60 is much better than your BB R50... get the one that is on offer... bear in mind you need a tool to remove/fit the bottom bracket, so it might be cheaper to just let the shop do it if you don't have it.
    PS if it lasted two years, I'd say it's not that bad
    left the forum March 2023
  • The Rookie
    The Rookie Posts: 27,812
    Have a look on eBay, you can pick up the higher end ones used for about a tenner, I'm still using an XT one bought 3 years ago for my MTB on my commuter (the MTB got an XTR).
    The bearing cups are the same its just the centre tube that is different between MTB and road.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • keef66
    keef66 Posts: 13,123
    They'll all fit into your BS threaded BB shell. New ones are cheap enough; just go for whichever you can find discounted. I replaced my 105 with an Ultegra one and it seems to be lasting a bit longer than the original, but that could just be pot luck.

    If you go for one of the newer 5800 / 6800 series bear in mind they are smaller externally so you'll need a different tool or an adapter to install them
  • The Rookie wrote:
    ... The bearing cups are the same its just the centre tube that is different between MTB and road.

    Unfortunately (again) it's not as simple. There are two other differences:
    - Compared with MTN cups, ROAD cups are 1 mm wider (11 mm vs. 10 mm).
    - Further, MTN cups have more threads (at least on the drive side).

    So while I am not saying they are not compatible at all, these differences shold be considered when mixing.

    Further, as mentioned before, Shimano invented two new designs in addition to the original 44 mm cups:
    - 39 mm cups (XTR, Dura Ace)
    - 41 mm cups (SLX/XT, 105/Ultegra).

    Which makes the tool part a bit more complicated than it has to be ...

    For clarity, the above refers to Shimano Hollowtech II cups.
  • The Rookie
    The Rookie Posts: 27,812
    Sorry, I should have used 'compatible' not the same!

    In fact I'm using the MTB centre tube as well at road bike width by cutting off the abutment shoulders, plenty of room for the ends of the tubes in the cups.
    Currently riding a Whyte T130C, X0 drivetrain, Magura Trail brakes converted to mixed wheel size (homebuilt wheels) with 140mm Fox 34 Rhythm and RP23 suspension. 12.2Kg.
  • smoggysteve
    smoggysteve Posts: 2,909
    An Ultegra BB will cost less than 10 quid and a BB removal tool a further 10 ( so long as you get the offside arm pre tensioner tool on it.) Easy to do yourself again and again.

    This is all you need. The BB has lasted pretty well if it's lasted a few years. I did this exact same swap out from square taper to 105 on my old Bianchi Via Nirone.
  • MJS996
    MJS996 Posts: 20
    Thanks for all the help guys - seems a lot simpler now. No longer convinced the BB is the source of my clicking, but at least I feel ready to do it when I need to