Bottom bracket

Focus-rider
Focus-rider Posts: 126
edited September 2012 in Workshop
Hey folks, just came back from a ride today and can hear a bit of a crunching bearing noise from my bottom bracket. I've taken the cranks off and regressed it but it's still there. I've got a focus izalko with a press fit bb30 bracket. Any suggestions on a fix or a replacement. What benefit is there to installing a ceramic bearing bracket and if it's worth it any recommendations.
Ta

Comments

  • sungod
    sungod Posts: 16,887
    bearings in bb30 may need periodic maintenance, especially if you've done many wet miles (i've done mine 3 times already in this year of miserable weather)

    the crunching may simply be due to some cack getting in, or it may be the bearings are damaged, either through contamination or bad fitting

    take off the seals, give them a *complete* degrease, they should run 100% smooth grease-free, you can spin them up with fingers, if they're not smooth you'll need to replace them

    if they're ok, regrease, and make sure seals are correctly fitted when you rebuild

    ceramic bb bearings won't make much difference, other than to your pocket

    steel fsa or sram ones should be fine
    my bike - faster than god's and twice as shiny
  • When you say remove the seals are you just talking about the three washer seals? I have never removed the bearings as I dont have a press. I have removed all grease and reapplied which mde a bit of difference but not perfect. May see about getting them replaced. Ta for the heads up about ceramic ones, don't mind spending more money if it's going to be a benefit but work to hard to waste it. it's the fsa ones I'm currently using with an fsa carbon crank. Forgot to mention I've only got about 2500 miles out of these, is that normal?
  • sungod
    sungod Posts: 16,887
    When you say remove the seals are you just talking about the three washer seals? I have never removed the bearings as I dont have a press. I have removed all grease and reapplied which mde a bit of difference but not perfect. May see about getting them replaced. Ta for the heads up about ceramic ones, don't mind spending more money if it's going to be a benefit but work to hard to waste it. it's the fsa ones I'm currently using with an fsa carbon crank. Forgot to mention I've only got about 2500 miles out of these, is that normal?

    they should last *much* longer

    i've done over 25,000km on mine so far, including many many wet miles, with some monsoon-like rides washing out half the grease, and i would be annoyed if they don't keep on running smooth for a long time yet

    rapid wear suggests they weren't fitted correctly, or, worse, that the bearing seats are misaligned/insecure, if this is the case then replacements could fail early too

    if it was a new bike, take it back to the shop and ask them to fix it, no way should the bearings fail that fast

    otherwise, you need to find out if the crunching is contamination or wear, a short period with some crud shouldn't trash them, so cleaning may be all they need, but if it's wear/failure then the root cause needs to be determined

    the seals can be popped out, use a fine needle, just be careful nor to tear/buckle them (you can get spares but it can be a hassle), this video shows someone cleaning bearings...

    http://www.youtube.com/watch?v=Cou3nLe3wwM

    if you can't remove the complete bearing, you can just take off the seal on the exposed outer face, you'll need to use a can of spray solvent to blast out the old grease, once that's done, stick a couple of fingers inside and turn the bearing to feel for any roughness (it won't spin freely due to the seal on the hidden side)

    if it's rough, replacement time - make sure the mechanic understands there may be a problem with the bearing seats that needs fixing to avoid a repeat failure

    if it's ok, repeat for the other side

    once both are clean/smooth, wipe out the inside of the bb, there's probably some crud in there, plus you want to get all the solvent out

    when you're sure the solvent is all gone, use a syringe to pump grease right into the bearings, then as you replace the seal it should squish out, put some more grease on top of the seals and then there's usually a loose cover ring that goes on top (packing fully with grease adds a little drag, but means i can go longer between servicing)

    replace cranks and follow the instructions to set preload
    my bike - faster than god's and twice as shiny
  • Thanks for that, judging by what your saying I maybe haven't cleaned them out as well as I should. My bike is ridden most of the year so plenty of wet dirty ride outs nd commuting. May give it another go before I take it to bike shop. Ta or te help.