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How stiff should BB30 be?

mortimer2000mortimer2000 Posts: 7
edited May 2014 in Workshop
I've recently bought a secondhand bike with bb30. With the chain off there feels like there is a fair amount of resistance and if you push the pedal with your hand (no chain attached) the crank doesn't spin freely for very long at all. With my older bikes the crank would always spin freely for a long time. Do I need new bearings or is it simply the way the bb30 is? I've taken off the crank and the bearing feel quite stiff but smooth with none of the creaks or noises I've heard about.

Thanks, Mortimer.

Posts

  • drlodgedrlodge Posts: 4,824
    BB30 is just the way the bearings are located (interference fit) and the dimensions of the bearing/spindle assembly. Sounds like the bearings to me, although if the interference fit is really tight, it could possibly squeeze the bearing internals.

    Replacement bearings are cheap enough, getting them swapped over is more tricky.
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
    Find me on Strava
  • keef66keef66 Posts: 13,123
    I don't think it's confined to BB30; most of the recent outboard bearings suffer from drag because of the seals. As long as it rotates smoothly I'm sure it's fine.
  • drlodgedrlodge Posts: 4,824
    Ah yes, seals. Could be the seals in the sealed cartridge bearings...
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
    Find me on Strava
  • sungodsungod Posts: 13,523
    with the crank off, without removing bearings you should be able to remove the outside seals and look at the condition, use a pick to carefully remove the seals, if the bearings are dirty/dry, time for a clean and/or grease
    my bike - faster than god's and twice as shiny
  • jgsijgsi Posts: 5,025
    I would prepare to disassemble ... have some new bearings ordered off Ebay or wherever... or get a bearing kit from Wiggle that has a few more shims. the wavy washer on the ND side is supposed to be fully preloaded.. and this depends on the number of plastic shims you use... no rule of thumb it is .. if you have a non freely spinning crank, you may need to add or even take some away.
    The crank should be solid but able to spin around a bit.. you'll know when it feels right as it doesnt at the moment.
  • Old_TimerOld_Timer Posts: 262
    JGSI wrote:
    I would prepare to disassemble ... have some new bearings ordered off Ebay or wherever... or get a bearing kit from Wiggle that has a few more shims. the wavy washer on the ND side is supposed to be fully preloaded.. and this depends on the number of plastic shims you use... no rule of thumb it is .. if you have a non freely spinning crank, you may need to add or even take some away.
    The crank should be solid but able to spin around a bit.. you'll know when it feels right as it doesn't at the moment.

    This, and watch the amount of tension that is put on with the pre-load adjuster also. Getting everything cleaned well and quality bearing cartridges that you install correctly will determine whether the BB lasts and doesn't make noises. The bearing and washer kits are not really expensive, shop around a bit at the bicycle shops and on line for your best price. Be sure you grease the seals well so they don't drag on the spindle when you assemble things, it makes a big difference in how things feel.
    Lets just got for a ride, the heck with all this stuff...
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