Bottom bracket play
- Thread starter Andywinds
- Start date
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gbb
Legendary Member
- Location
- Peterborough
Modern BBs tend to be cartridge type, or external cups. Tthere are no user serviceable parts or access inside cartridge types. External BB..you can replace bearings but need to press the bearings out, depending on type. Basically its easier to buy a new BB.
Yes, you'd need a tool depending on BB type.
Yes, you'd need a tool depending on BB type.
gbb
Legendary Member
- Location
- Peterborough
Im not experienced with MTB compatability etc...I'll let someone else advise.
Gravity Aided
Legendary Member
- Location
- Land of Lincoln
Anything that fits should work okay. By fits, I mean along the two parameters involved. First, measure your BB shell, the part left after you take all the hardware out, and then measure the length of the spindle. Both of these measurements should be close to the original component. If all goes well, and no problems crop up. Then you just add the cranks and hope it all lines up perfectly.
mrandmrspoves
Middle aged bald git.
- Location
- Narfuk
You almost certainly have a cartridge BB unless your bicycles is quite old or very cheap. Shimano UN55 is a cheap cartridge replacement that will give good service. You probably have a 68mm shell - but measure to be sure, and then choose the correct axle length and type (probably square taper)
If you haven't got one already, you will need a crank extractor tool - unless you happen to have self extracting cranks.
Buy the Park Tool if you wish - but there are many perfectly adequate alternatives such as Ice Toolz that are a lot cheaper and will give good service for the average user.
If you haven't got one already, you will need a crank extractor tool - unless you happen to have self extracting cranks.
Buy the Park Tool if you wish - but there are many perfectly adequate alternatives such as Ice Toolz that are a lot cheaper and will give good service for the average user.
Cubist
Still wavin'
- Location
- Ovver 'thill
SRAM GXP axles are NOT interchangeable with Shimano Hollowtech 2. no doubt someone will be along to say you can bodge it with a spacer, but my advice is to replace your BB with a GXP.
L
Cubist
Still wavin'
- Location
- Ovver 'thill
SRAM GXP is an external bearing system, with a 24 mm axle and two piece crank, not compatible with UN55. GXP stands for Giga Ex Pipe or some such nonsense.
mrandmrspoves
Middle aged bald git.
- Location
- Narfuk
Missed that bit in the OP - I stand corrected thanks.
slowmotion
Quite dreadful
- Location
- lost somewhere
I had a weird clunking noise from my bottom bracket. It turned out that the bolt that held the crank onto the shaft had worked loose and that all it needed was tightening up. It's worth checking that.
Cubist
Still wavin'
- Location
- Ovver 'thill
SRAM GXP is self extracting. On the non drive side is a 10mm hex aperture, through which you pass an 8mm hex key, into the hex slot of the bolt inside. Turning the hex key anti clockwise undoes the inner crank arm bolt and as you do, the action pulls the crank arm off the axle. Worth checking for play as you say, but in truth GXP BBs are notorious for short bearing life as they are often exposed to water ingress, especially if the owner gets enthusiastic with the dreaded pressure washer.
OP
OP
Andywinds
Senior Member
Thanks all. I think you are right Cubist, the GXP is 24mm, the body going from the spec sheet from Specialized says "SRAM GXP BB for 2pc, 73mm shell". And yes I used to get "enthusiastic with the dreaded pressure washer".
I am going to order this one
http://www.wiggle.co.uk/sram-gxp-team-bottom-bracket-cup-set/
Along with this tool
http://www.wiggle.co.uk/lifeline-performance-external-bottom-bracket-wrench/
How can I check that this BB will fit a 73mm body?
I am going to order this one
http://www.wiggle.co.uk/sram-gxp-team-bottom-bracket-cup-set/
Along with this tool
http://www.wiggle.co.uk/lifeline-performance-external-bottom-bracket-wrench/
How can I check that this BB will fit a 73mm body?
Cubist
Still wavin'
- Location
- Ovver 'thill
Yep, that BB will fit, and the tool will too. 73mm shells are standard, and yours will be English thread so you know which option to choose. The BB cups may come with a selection of spacers so that it will fit both 68 and 73 shells. Obviously you'll need fewer spacers for a 73.
Remember when removing the current BB cups, that the drive side is reverse thread, so clockwise to loosen.
OP
OP
Andywinds
Senior Member
Hi, wow I'm getting really confused at Wiggle. They are advising that I opt for the Italian 70mm thread... Even though the English should be for 68/73mm
"The Italian threaded option in this bottom bracket will be 73mm, the 70mm mentioned in the 'About Bottom Brackets' section will be general information."
Surely the 70mm is for road bikes??
And this is what they said about the spacers
"These spacers will relate to the chain line of the bottom bracket"
"The Italian threaded option in this bottom bracket will be 73mm, the 70mm mentioned in the 'About Bottom Brackets' section will be general information."
Surely the 70mm is for road bikes??
And this is what they said about the spacers
"These spacers will relate to the chain line of the bottom bracket"
Cubist
Still wavin'
- Location
- Ovver 'thill
Ignore whomever told you this. A 73 mm Specialized MTB shell will be English threaded. You need the version that fits 68/73.
As for spacers, well, I stand corrected, you don't need them. (On a Hollowtech 2 system you can add or remove spacers or BB mounted accessories and need spacers to ensure the width is the same.) Presumably with Truvativ/SRAM the axle width determines the fit.
Have a look here for a round up of external bearing info.
http://www.parktool.com/blog/repair...ype-campagnolo-ultra-torque#article-section-5
