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2012 Giant XTC composite XT 1X converstion BB / crank question

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2012 Giant XTC composite XT 1X converstion BB / crank question

Old 06-29-16, 02:53 PM
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stockae92
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2012 Giant XTC composite XT 1X converstion BB / crank question

The bike in question is a Giant XTC Composite from 2012. I am thinking of converting from SRAM X7 2x10 to Shimano XT M8000 1x11.

Do I need a new BB? How about crank option? Would a XT M8000 crank (32T) for press fit BB fits?

Thanks
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Old 06-29-16, 02:57 PM
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From the spec, looks like the stock BB is a SRAM GXP Press Fit
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Old 06-30-16, 11:07 AM
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bikeme
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Aren't BBs all the same? Sorry I don't know for sure. What I do know is that I love my Shimano M8000 1x!!! Good choice.

Related to this is that you probably don't need to change your crank, I had a 2x Shimano XT (c. 2013) and just put a Race Face (or Wolftooth) narrow-wide chainring on it. I even did that with my daughter's SLX triple--now she has a 1x at age 11 :-) You just need a M8000 11-spd clutched RD, cassette, chain and a shifter plus the chainring (RF or WT are my choices) and cable w/ housing. Save some $ and change out only what really needs to be upgraded. After thought edit: What hub is on your rear wheel? M8000 will fit hubs that accept 9-10-11 spd. Shimano. Sram hubs are diff fit and might need an adaptor or may not work at all--not sure, sorry.

Last edited by bikeme; 06-30-16 at 11:16 AM.
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Old 06-30-16, 11:32 AM
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Bottom brackets get confusing quickly. Long story short, SRAM GXP bottom brackets are not compatible with Shimano Hollowtech II cranks. Shimano cranks have a 24mm spindle. The GXP cranks also have a 24mm spindle but with a step down to 22mm on the non-drive side.

If the OP has SRAM cranks then they'll need a new BB to install Shimano XT cranks.
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Old 06-30-16, 01:10 PM
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stockae92
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You are telling me ... the BB standards are all over the place. And it doesn't help it has been +10 years since I put together my own bike ...

from what I read, seems like I need a shimano BB91 kind of BB, I guess that's what I am going to try and see if that's going to work
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Old 07-07-16, 03:24 PM
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OP, why do you need to change out the BB and crankset? Just change rear shifter/derailleur, chain, cassette, chainring (to NW), and remove FD/shifter. If needed, some spacers and longer chainring bolts for a better chainline. Done.

Doing this with my brother in law's '14 XTC carbon.
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Old 07-07-16, 07:06 PM
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https://www.chainreactioncycles.com/u...t/rp-prod61801

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