bottom bracket

lock
lock Posts: 32
edited October 2009 in Workshop
ive just fitted a new bb to my bike,its an ultegra one but when i spin the cranks round feels ok but not that free,it feels smooth but doesnt spin much once i let go?should it

im fairly new to doing my own repairs and i want things spot on
tony

Comments

  • MikeWW
    MikeWW Posts: 723
    Have you fitted the spacers correctly? and assume you have pulled up the non drive side crank hand tight only?Especially with new bearings there will be a little bit of resistance i.e wouldn't expect to just to spin freely
    www.lichfieldccc.org.uk
  • dennisn
    dennisn Posts: 10,601
    lock wrote:
    ive just fitted a new bb to my bike,its an ultegra one but when i spin the cranks round feels ok but not that free,it feels smooth but doesnt spin much once i let go?should it

    im fairly new to doing my own repairs and i want things spot on

    If you're new at it and have doubts, ask a friend, who's at the very least done it before, to help you out. There are a few good videos out there and Shimano instructions are fairly clear. Still, make sure you know what you're doing. Trial and error isn't always the best way to learn.
  • lock
    lock Posts: 32
    there wasnt any spacers,i think i might be being a little fussy

    also ive change my cassette and chain.i had 10 speed but know 9 speed will i need to change rear mech ,thanks guys
    tony
  • dennisn
    dennisn Posts: 10,601
    I've tried to find that video that shows this being done, but no luck. It was on this site about a month ago. ANYONE????????????
  • GavH
    GavH Posts: 933
    you'll defo find vids of it being done on youtube - i did when i installed a 105 bb on my hack. I'm on the mobile at the mo so can't post any links.
  • desweller
    desweller Posts: 5,175
    Don't worry too much about the unloaded spin - an unloaded bearing system will spin most freely if it has no lubricant in it at all, so it's not a reliable indicator of performance under load.
    - - - - - - - - - -
    On Strava.{/url}
  • gkerr4
    gkerr4 Posts: 3,408
    ^^ agreed - my experience of fitting and running hollowtech2 BB's (which I am assuming this is) is that they aren't that 'free running' when first fitted but if you were to take it off after a few hundred miles it would be much free-er running - but possibly still not as "spin forever" as a trad style square taper BB.
  • lock
    lock Posts: 32
    cool ,yeh i think this is the case ,thanks again for your help guys
    tony
  • lock
    lock Posts: 32
    thanks for advice fitted bb new cass and chain all working nice,lucky i live close to bike shop i kept getting wrong bits,lucky i didnt order of the net
    tony
  • ride_whenever
    ride_whenever Posts: 13,279
    Sounds normal, assuming that the bb shell was faced properly.

    Used cranksets do spin spin a bit freer once the seals have loosened up a bit, still nothing like the old square taper.
    Neeermad
    Carbon 456
    456 lefty
    Pompino
    White Inbred
  • Simon Notley
    Simon Notley Posts: 1,263
    Yep, as said above, they don't spin freely when unloaded, the important thing is that the resistance doesn't increase very much when they are under load. Whether a BB is perfectly frictionless when you're applying zero power has very little to do with how it will perform when you start riding (which lets face it, is what matters).

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