Bottom Bracket creak

dinyull
dinyull Posts: 2,979
edited July 2014 in Workshop
Started getting a creak from the BB the past few weeks which has moved to a constant creak when spinning the pedals.

The bike is a Boardman Road Comp 2011, I'm not sure what brand/type the BB is but the crank is Truvativ Elita compact 50x36T - if that helps?!

I'm thinking it probably just needs greasing as it's never been done, however as my maintenance knowledge isn't the best I'm not even sure I can grease it IF it's a sealed unit.

Can anyone help?

Comments

  • drlodge
    drlodge Posts: 4,826
    Sounds like the bearings could be toast in which case you need to have the bearings replaced.
    WyndyMilla Massive Attack | Rourke 953 | Condor Italia 531 Pro | Boardman CX Pro | DT Swiss RR440 Tubeless Wheels
    Find me on Strava
  • dinyull
    dinyull Posts: 2,979
    Ok, found out that it's a SRAM GXP bottom bracket.

    Bearings, does that mean I don't need to replace the BB, just the bearings in the BB? Or is it just going to be easier to replace the BB?

    How long should I expect a BB to last? I've had the bike 3 1/2 years, it's been used pretty solidly for 2 of those in all weather - is that what I should be expecting? If not which BB would people recommend to replace?
  • Dippydog2
    Dippydog2 Posts: 291
    When mine was creaking we took it out and wiped away all the grease. Reinstalled it, no creaking.
  • dinyull
    dinyull Posts: 2,979
    Am I able to mix and match crank and BB? Or if I have a SRAM crank will I need a SRAM BB?

    Was looking to do a straight swap but the reviews for SRAM GXP BB are pretty average and it's £25. I can get a 105 BB with good reviews for under £10.

    Apologies, but the BB/Crank is the only thing on the bike I've never tinkered with so completely in the dark.
  • kennygalbraith
    kennygalbraith Posts: 101
    I had the same issues on my road bike, the chain was worn,BB was fine.
  • dinyull
    dinyull Posts: 2,979
    Chain and cassette were replaced last month.

    Not due to any noise I should add, snapped a chain and replaced the cassette at the same time to avoid any slip.
  • Bozman
    Bozman Posts: 2,518
    If it is the BB they were £19.99 at CRC.
  • dennisn
    dennisn Posts: 10,601
    Just a reminder that there are many things on a bike that can, and will, creak, and they all sound like they are coming from the BB.
  • StillGoing
    StillGoing Posts: 5,211
    dennisn wrote:
    Just a reminder that there are many things on a bike that can, and will, creak, and they all sound like they are coming from the BB.

    Yep. I've had a noticeable creaking when pedalling out of the seat on a ride today. Thought the BB needed a bit of repacking, but have tracked the creak down to a cable outer that had split at the end in the ferule. The slight movement of the bars was moving the cable causing the creak.
    I ride a bike. Doesn't make me green or a tree hugger. I drive a car too.
  • dinyull
    dinyull Posts: 2,979
    Ha, this thread seems to have turned into something I'm really not after.

    I'm not trying to diagnose where the noise is from, I'm almost certain it's the BB and looking to either re-grease the BB or replace the BB altogether.

    So, I'll ask again:

    Can I re-grease a sealed BB unit?

    If not, could I replace a SRAM BB with a Shimano BB and still expect the chainset/crank to be compatible?
  • mattsccm
    mattsccm Posts: 409
    I have exactly that with mine.
    1. You can lift the seals out and add grease. I wouldn't fancy totally degreasing them. It may work.
    2. My SRAM GXP BB lasted a few hundred miles on the road. You cannot just use a Shimano BB as the GXP axle is 24mm diameter on the RHS and 22mm on the LHS. Shimano axles are 24 both. You can get adaptors, try Ebay. Not convinced.
    Only today I fitted another BB that copes with both sizes by supplying an adaptor. It all goes together fine but it took ages getting the spacers correct as the dimensions of the BB are different to the SRAM one and I am not convince about bearing preloading as the SRAM one just tightens the crank up to a set torque whereas the Shimano setup preloads the BB. Seems ok after a short 25 mile spin though.
    Best option is probably either a much better SRAM BB, but its either cheap or well over £100 as far as I can see. Hope do converters and I would like to think that the quality would be good and that you could get some set up advice. No one has replied to my thread here asking for such help so I guess you are on your own a bit.
  • deer_dance
    deer_dance Posts: 44
    Dinyull wrote:
    Ha, this thread seems to have turned into something I'm really not after.

    I'm not trying to diagnose where the noise is from, I'm almost certain it's the BB and looking to either re-grease the BB or replace the BB altogether.

    So, I'll ask again:

    Can I re-grease a sealed BB unit?

    If not, could I replace a SRAM BB with a Shimano BB and still expect the chainset/crank to be compatible?

    The Q&A on Wiggle (see page 3) suggests that the GXP system is different to Shimano Hollowtech so your existing crank wouldn't fit. The BBs look similar but guess there must be a crucial difference, not sure what though.

    http://www.wiggle.co.uk/sram-gxp-team-bottom-bracket-cup-set/
  • mattsccm
    mattsccm Posts: 409
    Differences. See above!
  • Bozman
    Bozman Posts: 2,518
    I've just had a similar creak after replacing a GXP, no creak before but it creaked after installation.
    The creak occurred when the crank was under pressure and was fine when I was spinning along, I stripped and re-greased(where necessary) the BB, pedals, crank, bars, stem, headset and I even tried different wheels but it was still there.
    After some advice I stripped the headset and fork bung again, that cured it.
  • dinyull
    dinyull Posts: 2,979
    mattsccm wrote:
    Differences. See above!

    Cheers for your help.

    Started getting a bit of grinding out on sat so will have to decide which way to go sharpish.

Categories