1991 Trek 7000 bottom bracket size

[Jaggs]

I hope you can shed light on a bottom bracket question.

I have never needed to work out which size BB I needed, as the frames I've obtained have had the BB still. I've got my hands on a 1991 Trek 7000, without one.

So, the question is....which do I need?

After some googling, on a different site/thread, someone states 'The size you'd normally need for that crank/frame combo would be a square taper 73x127mm'

However after a quick measure, it looks more like a 70mm.

And will it likely be English threaded, or do I not need to worry about that?

Any help/advice as ever is appreciated!

 

[boy"O"boy]

Re:

Just going through the same bottom bracket issues with my Trek 8700.

If I run the Deore DX chainset, I'm currently using a 68 × 127mm UN55

Theres enough space on the chain set vs chain stay to actually run a 68 x 122mm if I wanted to continue to use the Deore DX

Once a Hero rightly points out on my thread that this is the recommendation from Sheldon Brown. He also mentions that his own Trek 7000 runs a difficult to source 132mm bottom bracket.

I'm looking to run a pair of cook bros racing on the 8700. These need a spindle length longer than the 127mm UN55 that is currently installed, so I've got a 134mm Stronglight bottom bracket heading my way.

So, I suppose it depends on which chain set you want to run really.

Cheers.
boy"O"boy

 

[Jaggs]

Re:

Thanks for the reply. I was reading your Trek thread, I always wanted one of those.

Reading that triggered this thought actually, because it suddenly occurred to me that not all BB's were the same.

I have a DX Chainset already, and I have a 68 x 127 BB on the way, so I will just have to see. As long as it won't damage the frame or anything, I'm happy.

One of those things I've never needed to question, until now!

Thanks again