Sram BB help
mr.b-campag
Posts: 413
in Workshop
Looking to put a shorter crank on the bike I bought recently - one of these:
https://www.bikes.org.uk/scott-addict-r15-2011-road-bike/
It came with a 172.5mm chainset and I've bought a 167.5mm. Only thing is the latter has outboard bearings on it and the bike doesn't. Obv. I won't be able to use that BB with the outboard bearings, but can I swap them for what is on the bike (press fit) and use the chainset I've bought?
This is the new chainset:
And this is the existing one:
To my untrained eye they look like the same GPX chainset. Can I (or 'my' mechanic) fit this 'new' chainset on the bike?
Thanks
https://www.bikes.org.uk/scott-addict-r15-2011-road-bike/
It came with a 172.5mm chainset and I've bought a 167.5mm. Only thing is the latter has outboard bearings on it and the bike doesn't. Obv. I won't be able to use that BB with the outboard bearings, but can I swap them for what is on the bike (press fit) and use the chainset I've bought?
This is the new chainset:
And this is the existing one:
To my untrained eye they look like the same GPX chainset. Can I (or 'my' mechanic) fit this 'new' chainset on the bike?
Thanks
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Comments
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If the old chainset is GXP and not BB30, then you shouldn't have to touch the BB itself. Just pull the old chainset and insert the replacement.0
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Thanks me-109 - any way of knowing without removing the one that's in there atm (which I almost certainly don't have the tools for)?0
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It's almost certainly GXP. GXP has the bolt on the non-drive side, BB30 and DUB have it on the drive side. Removal is just with an 8mm hex key by the way, they have a self extractor built in.0
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Ah ok thanks, an 8mm hex key I should be able to manage. Assuming it is a GXP does the 'new' bb with the outboard bearings just slide off (I guess I have to remove the spider on the drive side)?whyamihere said:It's almost certainly GXP. GXP has the bolt on the non-drive side, BB30 and DUB have it on the drive side. Removal is just with an 8mm hex key by the way, they have a self extractor built in.
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Spider removal not required. Use the smaller hex key/bolt not the larger - that's what the small one presses against. Standard right hand thread IIRC - anticlockwise to loosen. You might need a tapping stick to get the axle moving out of the frame. If the threaded BB doesn't just slip off you might need to lever against the inside if the spider or hold the BB and tap the end of the axle. Don't hold the chainset too far off the ground if you do that.0
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If its on properly you'll need more than a hex key ,never got 1 off without a 2ft breaker barmr.b-campag said:
Ah ok thanks, an 8mm hex key I should be able to manage. Assuming it is a GXP does the 'new' bb with the outboard bearings just slide off (I guess I have to remove the spider on the drive side)?whyamihere said:It's almost certainly GXP. GXP has the bolt on the non-drive side, BB30 and DUB have it on the drive side. Removal is just with an 8mm hex key by the way, they have a self extractor built in.
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