Fitting XT cranks, is there something missing?

noidea · April 2010

Hi,

This is my current crappy gear setup which is all worn down (this pic if 4 years old) and im gradually replacing all the components with XT bits.

I have just bought some cheap second hand XT cranks and want fit them on my Giant, im guessing I need a new BB as my old cranks have a square tapered axle underneath the cover bolts.

These are the cranks I bought, am I correct in thinking that all I need to buy now is a new compatible BB such as this:
http://www.chainreactioncycles.com/Mode ... elID=41445

To me it looks like there is supposed to be an axle that is part of the cranks, which slides into the BB or does this come with the new BB?

Thanks guys and sorry about the crappy iPhone cam pics.

supersonic · April 2010

The cranks you have and the ones you link too are completely different - yours use the Octalink cartridge bottom bracket, the linked ones use an external bottom bracket with integrated crank axle.

ride_whenever · April 2010

nope, you've got hollowtech cranks...

You need an octalink bottom bracket of the correct length, i *think* it will be the same as the one on your current setup which will probably be square taper.

noidea · April 2010

Thanks for clearing that up so quickly gus 8)

Im not going for this one specifically (as its £50!) but an Octalink BB such as this:
http://www.chainreactioncycles.com/Mode ... delID=1205
But of the correct length is all I need?

Will I also need some of these bolts?
http://www.chainreactioncycles.com/Mode ... elID=18775

Thanks again and bare with me as I haven't really touched gearing before.

supersonic · April 2010

The XTR BB does not fit XT cranks.

Type the model number of your crank into Shimano Tech Docs search engine to find out what length axle you need. ES25, ES50/51 ES70/71 are compatible.

They usually come with the bolts.

noidea · April 2010

Right so these cranks are "FC-M752 Octalink Crankset"
http://techdocs.shimano.com/media/techd ... 611898.pdf

It doesn't list which length BB to buy but this site suggested that the ES25 is compatible with the M752:
http://www.rei.com/product/753546

supersonic · April 2010

It was in a weird place lol.

You need a 113 for a 47.5mm chainline, or a 118 for a 50mm chainline.

ES25 is compatible, but the bearings are better the higher the number is.

noidea · April 2010

I have measured the chainline to be 50mm but im not certain so im going to email Giant, which means this should be spot on as its a higher model as well:

http://cgi.ebay.co.uk/SHIMANO-SEALED-BB ... 3efd7d597c

Thanks for your help!

EDIT: They have an E-Type model for the same price, any ideas?

supersonic · April 2010

You will need to fit a 2.5mm spacer on the driveside if use etype BB.

Or an etype front mech lol.

Do check the frame shell width too.

noidea · April 2010

Damn, the shell width measures 68mm, so I gotta try and find a 118x68!

supersonic · April 2010

Try this:

http://www.lessthan.co.uk/product_info. ... _id=103393

or this:

http://www.onyourbikeonline.co.uk/produ ... _id=103393

noidea · April 2010

Nice finds, also found this which is a higher model but double to price:

http://cgi.ebay.co.uk/Shimano-Splined-E ... 2eac961609

Once I can confirm the chainline is 50mm im probably going to order one of those two you linked, thanks again for all your help! 8)

supersonic · April 2010

50 is what most modern cranks are anyway, and is the safe choice.

Two cheaper ones sounds better than one expensive lol, but I think the 5 is lighter.

noidea · April 2010

Screw it, just ordered the ES50 lol.

Fitting XT cranks, is there something missing?

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