Forum home Road cycling forum Road general

crank and bottom bracket queries

custom-freakcustom-freak Posts: 85
edited July 2007 in Road general
hello am in the process of getting together the bits for my fixie project and have got to the crankset, i have a campag crankset and a shimano copy crankset and was wondering about the bott5om bracket lengths, they are both doubles and i will buy the ring for whichever one seems suitable, the frame is either going to be an old road bike or a converted mtb frame, the hubs are on-one track with the cnc sprockets, i have seen the miche bottom bracket, is this adjustable for position? which taper is it? jis or iso?

thanks
cf

Posts

  • You can't sort out the bottom bracket assembly until you have decided on the frame because the width of the bottom bracket shell (on the frame) determines the length of the axle.

    Marv
    What tree ? ...........

    Trek 8000 ZR XC hardtail.
  • You can't sort out the bottom bracket assembly until you have decided on the frame because the width of the bottom bracket shell (on the frame) determines the length of the axle.

    Marv

    Don't quite see what you mean there. The required length of the BB axle is dependent wholly on the chainset and the required chainline, which in itself depends on the hub.

    However you are right in saying that you can't decide on the BB before you choose the frame because you buy a bottom bracket for the correct shell width, but with the axle length to suit your chainset and chainline.
    "Swearing, it turns out, is big and clever" - Jarvis Cocker
  • hello, i know that i need the frame before picking out the bb, i am 99.9% sure though that it will be an english 68mm bottom bracket as that is what is fitted to most of the bikes that come my way, the main thing i was hoping to find out was whether the miche bb was compatible with campag cranksets and whether there is the ability to adjust the postion of the botttom bracket a little to line it up, there don't appear to be sholders on the miche bb so thought i would ask. was hoping that someone might have tried this before and could point out any pitfalls to me, this is my first fixie build (although not my first fixie) and i want to get it right.
    Ta Cf
  • Monty DogMonty Dog Posts: 20,614
    I think I've also answered your same question on the 'other' board. Miche BB is ISO taper, so compatible with Campag crank - but it does matter what model of crank you have as Record and Chorus use a 102mm BB with Centaur, Veloce and previous models generally 111mm - Miche BB is 107mm - so probably means you can run chainring in outer position to get correct chainline, provided there's enough clearance between inside of crank and chainstay. Floating cups on either side of Miche BB mean you should be tune chainline to perfection. However - if you are using an old MTB frame, chainstay clearance could be an issue so I'd stick to a road frame.
    Make mine an Italian, with Campagnolo on the side..
  • thankyou monty that was exactly what i wanted to know, will be waiting to see what comes my way in road frames but if i get really impatient might have to use a mtb frame as a stop gap measure. btw is there a jis taper bb available with the floating cups? the chainset is veloce so 111mm, if i had anything nicer it would go on the geared bike

    Thanks again

    Cf
  • DavidBelcherDavidBelcher Posts: 2,684
    As a follow-up; you can run a Campag (ISO) taper crank on a Shimano (JIS) taper BB, but not the other way round as the Shimano crank won't seat properly on the Campag axle. But if you do use a Campag crank on a JIS-taper BB set, the crank taper will deform slightly to fit the BB, so you're stuck with that combo and can't go back to using ISO BB sets (though it does work without any grief - I've run a Campag Mirage chainset with JIS-taper Stronglight JP400 and Shimano UN52 BB sets for nigh-on 4 years now with no bother).

    David
    "It is not enough merely to win; others must lose." - Gore Vidal
  • Monty Dog wrote:
    I think I've also answered your same question on the 'other' board. Miche BB is ISO taper, so compatible with Campag crank - but it does matter what model of crank you have as Record and Chorus use a 102mm BB with Centaur, Veloce and previous models generally 111mm - Miche BB is 107mm - so probably means you can run chainring in outer position to get correct chainline, provided there's enough clearance between inside of crank and chainstay. Floating cups on either side of Miche BB mean you should be tune chainline to perfection. However - if you are using an old MTB frame, chainstay clearance could be an issue so I'd stick to a road frame.


    thanks for that i was wondering about an old campag daytona chainset and miche bb on a road frame i've got spare.
Sign In or Register to comment.