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124.5 bottom bracket (first rebuild) help

Hi everyone,

I have an old trek 4300 disc from 2008.
Im trying to get this back on the road, I've had to cut the crank off with a grinder as it was stuck solid. This was an SR Suntour.

First time I've done this since my BMX days.

I've removed the bottom bracket which was also seized. But cannot find an exact match anywhere.

It is a VP-BC 73T square tapered I'll try posting a pic but not sure it will show up.

So the bike needs a new crank and bottom bracket and front derailleur.

I have earmarked a Shimano Altus FC-M361 7/8
That's on eBay, but I need advice if this will fit and work with the 8 speed cassette which is in good condition.

I've read the other posts on the bottom bracket size that a 122 may be ok providing there is clearance for the crank, but with the old one cut in half and I haven't purchased the new one yet I've no way of knowing.

The old bottom bracket is 73x124.5 would a 122 be ok with the afformentioned crank ?

Also not sure what front derailleur I need either so any help on that will be very much appreciated also.


  • mully79mully79 Posts: 283
    Now you've cut the cranks off you dont need to limit crank choice by sticking to an old standard like square taper.
    also why 8 speed ? Are the shifters part of the brake levers ?
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