square or external bottom bracket?

stefano
stefano Posts: 254
edited November 2014 in Workshop
after removing the square taper bottom btacket from my fixed bike the thread was a bit damaged on the non-drive side. Now I want to get new bottom bracket and cranks also.
Shall I get again a square bottom bracket or I should go for an external one like Omnium cranks with SRAM GXP BB?
What whould put less presure on the damaged threads on the frame?

Comments

  • arlowood
    arlowood Posts: 2,561
    Theory would suggest that a replacement square taper would be the way to go. With the square taper the bearings are "inboard" pretty much within the shell of the BB - therefore they should experience less bending/twisting forces compared to a Hollowtech type BB where the bearings are external to the main shell.

    Thus if your threads are a bit suspect I would go for a square taper replacement.
  • keezx
    keezx Posts: 1,322
    Cartridge square taper BB is fit and forget if you buy a decent one.
    Can last years without any attention.
  • stefano
    stefano Posts: 254
    any tested good square BB?
  • Shimano, Shimano, Shimano.. the UN 55 is the only bottom bracket for outdoor cycling left... all the others are track BBs, which means they don't last long if they get wet.
    I've got a 110 mm new still in box that I don't need if you want it... that's for JIS cranks and 68 mm British BB, which fits most bikes/cranks
    left the forum March 2023
  • lpretro1
    lpretro1 Posts: 237
    Just get your LBS to rechase the bb threads :D
  • lpretro1
    lpretro1 Posts: 237
    Just get your LBS to rechase the bb threads :D
  • stefano
    stefano Posts: 254
    The frame has been rechased, though, it is alu and some damaged is left. I will probably go for Miche advanced chainset with 144 BCD that takes 107 JIS BB.
    Any other suggestions are wellcome ...
  • sheffsimon
    sheffsimon Posts: 1,282
    Shimano, Shimano, Shimano.. the UN 55 is the only bottom bracket for outdoor cycling left... all the others are track BBs, which means they don't last long if they get wet.
    I've got a 110 mm new still in box that I don't need if you want it... that's for JIS cranks and 68 mm British BB, which fits most bikes/cranks

    Got to disagree with you...had a Campag Centaur square taper in my winter bike for at least 5 years, still runs smooth with no play, and it's been through all kinds of weather.

    On the other hand, before that I used Campag Veloce and they were sh**e....
  • marcusjb
    marcusjb Posts: 2,412
    Royce square taper - fit and forget. Tens of thousands of km in year round conditions on the distance bike - hasn't given me a bit of bother.

    Many dollar though.
  • Moonbiker
    Moonbiker Posts: 1,706
    SKF one is crazy money also.

    http://www.velovitality.co.uk/products/ ... om-bracket

    i'd get teh shimano
  • SheffSimon wrote:
    Shimano, Shimano, Shimano.. the UN 55 is the only bottom bracket for outdoor cycling left... all the others are track BBs, which means they don't last long if they get wet.
    I've got a 110 mm new still in box that I don't need if you want it... that's for JIS cranks and 68 mm British BB, which fits most bikes/cranks

    Got to disagree with you...had a Campag Centaur square taper in my winter bike for at least 5 years, still runs smooth with no play, and it's been through all kinds of weather.

    On the other hand, before that I used Campag Veloce and they were sh**e....

    You can't buy a Centaur square taper anymore, I think, besides, it's got a different taper from Shimano, so it won't even fit.
    left the forum March 2023
  • keezx
    keezx Posts: 1,322
    Centaurs are still available from lots of locations...
    Just one:
    http://www.wiggle.co.uk/campagnolo-cent ... m-bracket/
  • keezx
    keezx Posts: 1,322
    marcusjb wrote:
    Royce square taper - fit and forget. Tens of thousands of km in year round conditions on the distance bike - hasn't given me a bit of bother.

    For those ridiculous prizes you may expect it runs forever.
  • craker
    craker Posts: 1,739
    I'm running a sleeved / threadless bb on my ss. I've just replaced one after 18 months (as it was creaking though it turned out to be something else that was creaking).

    At £18 a go I need to get through 4 before I'll start kicking myself for not stumping up £80 for a replacement bb shell from Avon Cycles.

    Depends on your frame really.
  • marcusjb
    marcusjb Posts: 2,412
    Keezx wrote:
    marcusjb wrote:
    Royce square taper - fit and forget. Tens of thousands of km in year round conditions on the distance bike - hasn't given me a bit of bother.

    For those ridiculous prizes you may expect it runs forever.

    Nothing rediculous about the price if they do run forever (and they do seem to - my distance bike has only done around 35-40000km on one so far and I know people that do much bigger mileage than me with them).
  • keezx
    keezx Posts: 1,322
    Good for a trip around the world, but in the civilized world it's ridicilous.
  • marcusjb
    marcusjb Posts: 2,412
    Keezx wrote:
    Good for a trip around the world, but in the civilized world it's ridicilous.

    Why so?
  • dj58
    dj58 Posts: 2,221
    Plus 1 for Royce BB's, I have one that I fitted to my 1992 Kona MTB, still on the original bearings, still running as smooth as the day I fitted it. True fit and forget.
  • keezx
    keezx Posts: 1,322
    marcusjb wrote:
    Keezx wrote:
    Good for a trip around the world, but in the civilized world it's ridicilous.

    Why so?

    There should be a certain relation between quality and price.
    You can buy a good quality ST BB for 30, for 300 the relation is silly, unless you really need it going forever without any attention (who does?)

    Recenly I changed the bearings in a Chorus BB after 10 years of use, that's good enough for the 50€ the thing cost me....
  • stefano
    stefano Posts: 254
    I have benn through several BBs, all square taper. A sugino one lasted four years and 30,000 miles. The last one with carbon cell, the cell was detached from the threaded end causing the non drive cup to bite into my frame almost destroying the frame itself :cry: . That is the reason trying to find a good quality square taper or to explore the option of a BB with external cups like the SRAM GXP.
    I understand that the external cups can take larger diameter bearings that can last longer, but I am not sure if this is the case in practice?
  • stefano wrote:
    I understand that the external cups can take larger diameter bearings that can last longer, but I am not sure if this is the case in practice?

    No, they use 37 x 25 x 6 mm sealed units, which are quite under engineered for the job they have to do
    left the forum March 2023
  • DeVlaeminck
    DeVlaeminck Posts: 8,882
    I've not been overly impressed with the longevity of Campag square taper bottom brackets - I've a Chorus one in at the moment that has just started to develop a bit of play after only maybe 6-7000 miles. For what it cost that is not impressive.
    [Castle Donington Ladies FC - going up in '22]
  • keezx
    keezx Posts: 1,322
    Mine lasted 10 years and probably > 50000 km.
    It did not have play, but I mounted another one for another crankset and I noticed that 1 bearing was shot (it ran still fine)
    The bearings are sealed one side, so if water comes in the seat tube it goes fast, put in double sealed ones.
  • stefano
    stefano Posts: 254
    From the discussion I am between the Shimano UN55 and the SKF bottom bracket. Has anyone tried any of them? How long they last?
  • Semantik
    Semantik Posts: 537
    I run UN54 and UN26(cheaper) square taper bottom brackets in my winter and commuting bikes. Both done 5k+ miles without a whimper.
    I like square taper and have no issues with it.
    Except... where is the choice of suitable chainsets?
    If I want a square taper chainset I am looking at either Stronglight or some cheap 'n' nasty ones aimed at low end 8 speed bikes.
    If I want to spend, say, £70- £100 on a 53/39 JIS fit, what is out there?
    Not much from what I can see.
  • k-dog
    k-dog Posts: 1,652
    arlowood wrote:
    Theory would suggest that a replacement square taper would be the way to go. With the square taper the bearings are "inboard" pretty much within the shell of the BB - therefore they should experience less bending/twisting forces compared to a Hollowtech type BB where the bearings are external to the main shell.

    Thus if your threads are a bit suspect I would go for a square taper replacement.

    Ain't that the wrong way round - the more inboard the bearings are the more leverage you have so the more twisting/bending? That's the point of wider BB standards.
    I'm left handed, if that matters.
  • keezx
    keezx Posts: 1,322
    Pure theoretically external bearings with a large axle or wider BB with internal bearings are superior, no doubt about that.
    But in the daily praxis the old system still works sufficient for lots of cyclists, including me.
    Sugino-Stronglight are pretty much the only good and cheap ones left indeed.
    TA makes still some nice square taper cranks, but far too expensive.
    On my bike for races I use a FSA Vero Compact which serves me perfect with absolutely no issues, besides that it doesn´t look bling.
    I may change it to an older SRAM Force compact which I have laying around, but I´m still not convinced that it brings me any advantage.
    In the complete picture cranksets are low on the list of gains to be made.