Advice on Bottom Bracket / Chain-set: from 3x9 to 1x9

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Voinar

Active Member
Location
Lancaster, UK
Hi There


I'm looking for some technical advice on bottom brackets and chain-sets:

I have a Trek 7.3 FX (2014) bike which has the following 2 parts:

(a) Bottom bracket: Unknown square taper
(b) Chain-set: Shimano Acera M371

In the not too distant future I would like to switch from 3x9 drive train to a 1x9.

Unfortunately (b) has none removable chain-rings it's a cheap all-in-one unit so for this project it's a write off and will need replacing.

So based on this I would have to source a replacement triple chain-set that has removable chain-rings, so I can remove them all and fit something along the lines of a race face (or equivalent) narrow-wide chain-ring.

The problem is with (a) - I have no idea of the spindle length and I don't have any tool to remove the chain-set to measure it.

So I have no idea when I'm looking at a square taper chain-set on eBay whether it would fit correctly and give a good chain line or not.

I'm looking to do this as cheaply as possible and would like to avoid having to replace (a) as well as (b).

If anyone can shine any light on this for me or give any advice i would be most grateful.


Thanks

Jim
 

Tim Hall

Guest
Location
Crawley
You're going to need the tool to remove the chainset if you're going to replace it, so buy one and get measuring.
 
OP
OP
Voinar

Voinar

Active Member
Location
Lancaster, UK
You're going to need the tool to remove the chainset if you're going to replace it, so buy one and get measuring.
Good point - Though I may be able to borrow some tools for the job - still working on that one - but moving on let's say I remove the chain-set and measure it ...

UN55 BBs are so cheap** and last something close to forever so it's no biggie if you have to get a different length.
£7.99 at CRC !
Is there a general source of info and what chain-set needs what length of BB spindle - I guess I would have to check with the manufacturer?
 
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OP
Voinar

Voinar

Active Member
Location
Lancaster, UK
I have done some searching and anything that gave some info relative to this all mentioned the same thing:

The BB appears to be a UN26 68x123mm - but until I do get 100% measure I can look at what options are available if this should be the case.
 
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