Bottom bracket compatibility

by cavasta   June 5, 2013  

My Dawes Galaxy currently has a Shimano UN55 bottom bracket fitted (http://www.wiggle.co.uk/shimano-bb-un55-bottom-bracket-british-thread/)

Is it possible to replace the BB with one of the Hollowtech type BBs such as this one:

http://www.wiggle.co.uk/shimano-deore-bb51-bottom-bracket-cup-set/

This will then enable me to fit one of these chainsets:

http://www.wiggle.co.uk/shimano-fc-m590-deore-9-speed-483626t-triple-cha...

Reason for asking: I get quite a lot of flex with my current set up (UN55 BB and Spa Cycles XD-2 triple touring chainset) and I'm looking for a stiffer set up. What are my options?

Full current setup is:

Shimano UN55 bottom bracket
Tiagra FD4503 front mech
Spa Cycles XD-2 triple chainset (48-36-26)
11-32 9 speed cassette
Tiagra STI shifters
BB shell width = 68mm

4 user comments

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the bb should normally come with all mtb chainsets.

not sure how much stiffer you will find it but it should feel a little different.

posted by mathewshotbolt [100 posts]
5th June 2013 - 13:12

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mathewshotbolt wrote:
the bb should normally come with all mtb chainsets.

not sure how much stiffer you will find it but it should feel a little different.

Thanks for the reply. But will the BB be compatible with my frame (shell width 68mm) and front mech?

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posted by cavasta [210 posts]
5th June 2013 - 14:06

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I think you should be fine. Both are 9-speed triple setups, so the horizontal spacing of the chainrings should be the same. The Chainrings are the same size (same number of teeth), so the front mech should work.

Your bottom bracket will be compatible with the Deore chainset, and yes, the chainset will come with the bottom bracket.

two wheels good; four wheels bad

posted by cat1commuter [1364 posts]
5th June 2013 - 16:36

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cat1commuter wrote:
I think you should be fine. Both are 9-speed triple setups, so the horizontal spacing of the chainrings should be the same. The Chainrings are the same size (same number of teeth), so the front mech should work.

Your bottom bracket will be compatible with the Deore chainset, and yes, the chainset will come with the bottom bracket.

Cheers - just what I wanted to hear! Smile

cavasta's picture

posted by cavasta [210 posts]
5th June 2013 - 17:24

1 Like