bottom bracket

RyanMK43

i know you guys on here must get asked this all the time but how do i know what size bottom bracket i need? i have tried looking on the net for the spec of my bike but cant find anything about the BB. i would just take the old one out and have a look but i don't have the tools to do that yet as it is in my basket waiting for the BB to be put in with it any tips or help would be great. if its any help im riding trek 4500 2010 model

kdawg74

From the specs of the bike, i think this is the right BB for your bike

http://www.sjscycles.co.uk/shimano-bb-e ... prod20429/

cooldad

Measure the BB width and axle length.