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First and foremost.. I'm slowly trying to replace my bottom bracket.. it makes a kind of knackered-bearings sound when I move the pedals round without the chain attached. This is because I've been bad and not washed my bike after cycling out in the rain, snow and gritted/salty roads. Whoops :(

I have a Trek 1.5 2011 with a compact chain ring.

I'm having great difficulty identifying what sort of bottom bracket it has. I believe the crank is an FSA Vero, 50/34 if that helps.

Unfortunately the manufacturer does not provide any information on the bottom bracket.

How can I identify for sure what I have, what I need to get, and what tools I'll need to replace it? I really don't want to start spending lots of money on the wrong tools and the wrong parts.

Any help would be massively appreciated!

Thanks! John.

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FSA Vero Product Page: fullspeedahead.com/products/37/Vero-Compact-Crankset –  Benzo Feb 12 '13 at 23:12
    
Upon contacting Trek they confirmed it's a 68x110mm square taper bottom bracket. I'll confirm it went ok once I find time to order it and try and fit it! Having said that, I'll probably just try removing it first and checking. –  John Hunt Feb 13 '13 at 15:11
    
In case you intend getting new cranks any time soon - dump that square taper and get a more modern hallowtech or octalink one. Nuch less hustle and fewer tools to service, also lighter. –  Vorac Oct 16 '13 at 10:44
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2 Answers 2

up vote 3 down vote accepted

I'd ask Trek.[1] Most likely you have a 20-tooth splined bottom bracket that the Park Tool BBT-22 would remove[2], but check first. You'll also need to know what width the bottom bracket is (varies) and its threading (probably ISO).

You may be able to just replace the bearings and not the whole bracket. If you want to go that route, you're best off pulling the bottom bracket out and taking the bearings to a bike shop. Might be easier to just a whole new one, though; the races could be messed up if it is making "knackered-bearings" sounds.

You will also need a crank puller, like this one.[3] And a metric ratchet set.

[1] http://www.trekbikes.com/faq/contact.php

[2] http://www.parktool.com/blog/repair-help/bottom-bracket-tool-selection

[3] http://www.parktool.com/product/universal-crank-puller-for-square-taper-and-splined-cranks-cwp-7

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Thanks for a really complete answer :) I feel a bit more confident this will go right.. I've contacted Trek and if they can give me the info then I'll paste it here so that others may find out what's in their bike! –  John Hunt Feb 13 '13 at 10:09
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FSA Vero uses a standard JIS square taper bottom bracket. You can measure and see what size your existing bottom bracket is, see related question on how to measure.

How do I measure a bottom bracket?

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