Changing cartridge BB to hollowtech II

shmo
shmo Posts: 321
edited May 2008 in Workshop
Due to repeated crashes, knocks and general abuse of my chainset I was thinking about removing the cartidge bb and chainset on my Giant SCR and replacing it with a Tiagra 4500 hollowtech II one with a new Tiagra crankset. Question is would I need to get the frame "chased and faced" or would it likely be okay without?

Also if this is likely to be a problem and I shouldn't bother changing the bottom bracket does anyone know a budget triple chainset that would be compatible with the current cartidge bb and tiagra components on the giant scr?

Cheers.

Comments

  • maddog 2
    maddog 2 Posts: 8,114
    if the frame is painted then yes you should get it faced really. Otherwise the HT2 BB may well not last that long.

    your LBS should be able to do it for £10-15

    I'd get it done (if you intend to keep the bike a while) as the HT2 c/sets are much better IMO.

    If you run a bare frame, say ti, then it's not as important. I didn't face my ti frame and the external BB has been fine.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
  • gkerr4
    gkerr4 Posts: 3,408
    i didn;t bother getting my Trek Pilot 1.2 done when i fitted a tiagra HTII chainset - fitted fine and the BB lasted for ages (still there in fact..)

    HT is excellent by the way - well worth changing for.
  • shmo
    shmo Posts: 321
    Thanks very much for the replies.

    I'm not massively fond of the frame but it has mudguards and I need it for commuting and wet weather. Could definitely use the upgrade though as my pedals are gradually stripping the threads out of the cranks and the chainrings are slightly bent in places.

    Think I'll buy the upgrades and keep an eye out for cheap frames in the reader's ads to maybe transfer over in the future.
  • topdude
    topdude Posts: 1,557
    Hi, i fitted a Hollowtech chainset to my Trek Pilot 1.0. Before fitting the bearing cups i just carefully removed any lumpy paint from the BB ends with sandpaper on a wooden block. This left a nice smooth surface for the cups to seat against and it is running fine 1000 miles later.
    He is not the messiah, he is a very naughty boy !!
  • Dai_bach
    Dai_bach Posts: 16
    Definitely worth getting your BB shell faced before fitting a Hollowtech BB. Any unevenness can lead to the BB being misaligned, over stressing the threads. If you strip them, your frame will be knackered. It's only a small probability of that happening, but what is £15 or so quid for facing against a whole new frame (and BB unit)? Besides, it looks so much neater then everything is flush and square.

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