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Bottom Bracket

LittigatorLittigator Posts: 1,262
edited October 2008 in The workshop
HURRAH! Here we have our newest sub category in the Commuting forum for daft questions and silly qeuries

So here's mine first of all - my bottom bracket is starting to make a nasty noise, particularly when I am climbing out of the saddle and so putting it under a lot of stress.

Also, it's developed a sort of gluey sensation is the best way I can describe it, i.e. it feels a bit like someone has poured glue into the bearings, but only every now and then and only when I am pedalling forward but not when I'm back-pedalling.

Any thoughts anyone, is it just a case of a dab of grease (if so where) or does it need something more significant?

Thanks
Roadie FCN: 3

Fixed FCN: 6

Posts

  • What a daft question... :wink:

    I have no idea :lol:
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  • LittigatorLittigator Posts: 1,262
    Pah...what a silly answer and I thought it was the questions that were supposed to be silly

    :lol:
    Roadie FCN: 3

    Fixed FCN: 6
  • Get thee to a LBS and ask for the tool which you need to get the pedal doobrees off the bottom bracket (I think it's a crank puller), and a giant flat spanner to undo the cartridge, start on the chain side, mine was a wrong-way thread, then you can have a look yourself.

    Apparently the LBS normally charge what my friendly LBS man says is an 'extortionate amount' for inspecting the bracket.

    So, once you can see it, check for any rusty or dirty bits, if none are visible whack some grease in and put the whole thing back together. Having obtained the tools you;ll want to use them again, unless like me you borrowed them, so you can then replace your bottom bracket if need be! Hurrah!

    However, as these tools are pretty specific to this quite infrequent job, ask your LBS how much they charge to do it and weigh that against the price of the tools and the opportunity cost of getting annoyed and frustrated a lot.
  • biondinobiondino Posts: 5,990
    A word of warning - for some esoteric reason, most bad clicky clunky crunchy noises on a bike *appear* to emanate from the bottom bracket but they don't necessarily do in reality. I had a strange noise yesterday, which sure enough seemed to start down below, but eventually I realised it was my sunglasses knocking against the headset and, presumably, the sound traveling down the tube.

    Anyway, I also have some genuinely horrible noises I think are coming from mine too - I'm hoping a full service (this is the Trek rather than the Focus btw) will sort them out without me having to explore any further myself.
  • downfaderdownfader Posts: 3,686
    I had this horrible clicky crunchy sound on my bike last week. Checked it over and couldnt find where the hell it was coming from. Its only started this last couple of weeks and I was just about to phone the LBS when I realised something... standing there trying to rack my brians I started tapping on the pannier rack and realised that was it.

    Checked the weilding, sound. Screws, all sound. Flipped the bike over and figured out it was the metal flaps that secure under the shelf. Gonna put some silicone sealant on there just to deaden it :wink::lol:

    I think I can use it to fill the scars on me tyres too. :lol:
  • Head to the roadie board, and there's a "sticky" thread on strange noises eminating from bikes (as opposed to cyclists). Finding them can be a non-trivial excersise.

    Figure out if its the BB (does it feel lump when you turn it by hand without the chain on, for example?), then get to the LBS. The other way round can lead to lots of bills for them doing lots of meaningless things by process of elimination.
  • itboffinitboffin Posts: 19,954
    Littigator wrote:
    HURRAH! Here we have our newest sub category in the Commuting forum for daft questions and silly qeuries

    So here's mine first of all - my bottom bracket is starting to make a nasty noise, particularly when I am climbing out of the saddle and so putting it under a lot of stress.

    Also, it's developed a sort of gluey sensation is the best way I can describe it, i.e. it feels a bit like someone has poured glue into the bearings, but only every now and then and only when I am pedalling forward but not when I'm back-pedalling.

    Any thoughts anyone, is it just a case of a dab of grease (if so where) or does it need something more significant?

    Thanks

    If you're sure it's the BB then removing the whole thing for a proper inspection is surprisingly easy, I should know i've done it to all my bike recently.

    So a couple of questions to get started;

    1. Which make and model of bike?
    2. Has it ever had the BB serviced and or replaced?
    3. Does the BB turn roughly and or noisily?
    4. Have you checked for any obviously loose components?

    A good starting point I've found on my older bikes that clearly had never had a BB service was to flush the BB with WD40 (which is not a lubricant) several times then re-lub the bearings with a nice light Teflon grease.

    But really what you should do is take the BB out and check for signs of wear, not so easy if it's a sealed unit :) - even small pits in bearings and spindle can be very noticeable after a while.

    As ever Park Tools is a great source of knowledge http://www.parktool.com/repair/readhowto.asp?id=93
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  • Litt, sounds like the same thing that was happening to me. Horrid crunching noise's, that got worse if I tried to put any power down i.e when climibing or sprinting.

    I ended up getting my BB replaced when I had the bike serviced. The LBS said that they always scrimp on these on lower end bikes. Ho hum!
    Not to worried at the end of the day as it's a fairly vital part and I'd much rathe get started on the upgrades sooner rather then later!
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  • So many times this has happened to me and others? Often the creaking can be stopped by loosening and then re tightening the rear QR. I'm not saying it IS the problem but a cause to eliminate
  • nicklousenicklouse Posts: 81,520 Lives Here
    well it might help with what crank and bb set you have,

    Otherwise have a read though the diagnosing a noisy drive train topic on the parktools webby.

    It could be so many things.

    From wheel bearings to headsets.

    http://www.parktool.com/repair/readhowto.asp?id=123
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
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  • BuglyBugly Posts: 520
    From your post on the road forum - I would suggest that your external Bearings are shot, they are not user servicable but are relatively cheap and easy to replace.

    1) remove left crank arm, Assuming a hollowtech style crank undo the two allen keys

    2) undo the plastic cap which is used to preload the bearing.

    3) unclip the plastic divise attached to said allen bolt. This clip is used to correctly locate your crank arm on the axle.

    4) pull on crank to remove from axle.

    now the right side.

    5) remove chain from chain ring

    6) tap the axle on the left hand side with a rubber mallet (or place a block of wood on axle and tap that with a hammer). The crank and axle will slide out.

    7) Inspect the axle if worn you may be up for new cranks but this is not likely.

    8) using the appropriate spanner (cost in the region of 10 quid) undo the two bearings. Remember that they both will unscrew towards the front of the bike.

    9) place said bearings in the bin and replace with new ones. The bearings should come with a set of 3 spacers. If you have a road frame I think a single spacer on the chainwheel side is required.

    10) assemble in reverse order to above, Give the RHS a good tap to push into placem pushing the LH crank on last, you will know its correctly located when the plastic clip goes down.

    11) before tightening the allen keys remember to preload the bearings with the cap. Should be about 6 to 13 foot pounds. The little plastic tool that comes with the bottom bracket tool should not allow yout to over tighten.

    12) alternate between the two allen bolts tightening them to between 106 and 132 foot lb.

    put the chain on and you are good to go.

    BTW may be a good time to check the chain for stretch. Old chains wear out chainrings and clusters.

    Cheers
  • LittigatorLittigator Posts: 1,262
    Thanks all for the helpful replies...I feel a bit out of my depth but what the hell I'll give it a go anyway.

    The cranks and BB are as follows according to the website, if that makes any difference...

    CRANKS FSA Vero 46T
    BOTTOM BRACKET FSA BB-7420ST
    Roadie FCN: 3

    Fixed FCN: 6
  • cjcpcjcp Posts: 13,345
    The noise means you have to lose weight. :wink:

    There was a right ol' racket coming from my left crank a couple of weeks ago. Took it off, took the BB out, cleaned (sort of - it was before I set off for work) and re-greased it. It's now as quiet as a church mouse. For the moment...
    FCN 2-4.

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  • nicklousenicklouse Posts: 81,520 Lives Here
    Littigator wrote:
    Thanks all for the helpful replies...I feel a bit out of my depth but what the hell I'll give it a go anyway.

    The cranks and BB are as follows according to the website, if that makes any difference...

    CRANKS FSA Vero 46T
    BOTTOM BRACKET FSA BB-7420ST

    from your other BB post!
    Littigator wrote:
    The BB is an Ultegra 6500

    two very different set ups and things to look at.

    got a picture of your set up?
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • LittigatorLittigator Posts: 1,262
    nicklouse wrote:
    Littigator wrote:
    Thanks all for the helpful replies...I feel a bit out of my depth but what the hell I'll give it a go anyway.

    The cranks and BB are as follows according to the website, if that makes any difference...

    CRANKS FSA Vero 46T
    BOTTOM BRACKET FSA BB-7420ST

    from your other BB post!
    Littigator wrote:
    The BB is an Ultegra 6500

    two very different set ups and things to look at.

    got a picture of your set up?

    Ahhh, I can see the confusion...two very different bikes as well. The FSA BB is on my cheap fixie, the Ultegra 6500 is on my carbon roadie which both seem to be displaying similar symptoms apart from the roadie has the glueiness I've described.
    Roadie FCN: 3

    Fixed FCN: 6
  • nicklousenicklouse Posts: 81,520 Lives Here
    basically you are just going to follow the steps in the parktools link

    But when out on the bike(s)try and make notes of when and how the issues happen and make sure all joints are tight.

    with the cranks some pulling and pushing will show up slack fitted crank arms (Ultegra) while pulling in and out on the pedal will show up loose/worn arm crank interfaces.

    removing the chain and spinning the cranks will give two very different results for both bb set ups as one is ball bearings andthe other is a mix of needle and ball bearings.

    the ultegra is strippable and easily re greased. the other is not.

    i can post up a pic of the ultegra (XTR) one if you want.
    "Do not follow where the path may lead, Go instead where there is no path, and Leave a Trail."
    Parktools :?:SheldonBrown
  • Sealed Bottom Bracket: If your bottom bracket is a sealed cartridge unit (as most are nowadays), it can't be serviced or adjusted. If it grinds, wobbles, or catches, it must be replaced as a unit. Just remove the old cartridge and replace the entire thing.
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