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Converting road frame to commuter: HELP with BB choice


JFP.Urbike

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I am converting a roadie frame into a single speed commuter.

I have been been given a Shimano MTB crankset for free. But now I am confused as to which BB to put on the bike.

Do I put on a MTB BB and the put the spacers on the frame side?

Or do I put on a road BB to fit the frame and then put the spacers on the crank side (outside) of the BB?

 

Have I made a boobie by having to choose a BB?

 

PS: if anyone knows where I can get a set of FREE road brake callipers you would rock a lot!

Edited by 2Wheels1Smile
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Hey. In terms of a BB I'm not sure. But I'll be able to help you with calipers, they just don't have pads in. Send me your details if you're interested

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Hey. In terms of a BB I'm not sure. But I'll be able to help you with calipers, they just don't have pads in. Send me your details if you're interested

That would be BRILLIANT! #KeepingBikesAlive
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I expect that your BB is the regular British Threaded Kind and that you are installing an external Bearing Bottom Bracket? If its cartridge type the bottom bracket width matters (and there is no spacers).

 

Chain-line (frame center line to middle ring) on Road Bike is 43.5mm, on MTB that's usually 50mm. I'm guessing that you may not need to install the spacers (not sure if this will cause a problem with the hollowtech crank spindle to be too long though).

 

Then again as long as the SS chain is straight its all good, and you have all the space on the free hub body to ensure the gear at the back is on the correct place to ensure a straight chain.

Edited by johanpre44
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