BB Identity - How do you tell?

TGR

Old School Grand Master
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Good morning all,

Is there an easy way or any way to check what type of BB a frame has? Obviously without the benefit of having a BB installed.

I recently made a boob with a French freewheel which threaded onto a hub (which was Italian or English) quite easily - removal was anything but easy and i am still crying about it; therefore i would not like to make the same mistake with a BB.

Thanks all,

Richard
 
Richard, if you measure the shell width then it should be either 68 or 70mm. 68 will more than likely be english threaded, 70mm will be italian. French (rare) and swiss (even rarer) are also 68mm, but unless it's a french bike or a very obscure make a 68mm BB is 99% certain to be english threaded.

You can also try running a fingernail round the threads in the driveside to determine which way they go - if the threading is reversed then it's an english BB, if not it's italian.

Even when you think you've determined which type you have, take it easy threading in a new BB, just in case!
 
Thanks chaps, at last - something which is not too complicated!!! I will tread carefully though.
 
The tip with the fingernail is a good one to work out if it's right or left hand thread. Other way is to knock a pin into a small strip of wood and use instead of a fingernail :)

Shaun
 
I have a CBT Italia made in Italy with German Oria tubing and uses a French threaded bottom bracket. I later found that CBT was located near the French boarder and the bikes they made for the French market were French threading. I try to avoid French frames now as the parts are much harder to find.
 
ScillySuffolk":kft3jhf8 said:
"Everything You Wanted To Know About Bottom Brackets, But Were Afraid To Ask."

The third table from the bottom of the page is a table detailing the different threading and shell sizes.

The table below that explains the hilarious consequences of fitting the wrong BB to a given shell: fun for all the family!

So, based on Sheldon's page - take spare BSC cup without shoulder, drop into BB shell, if it falls right though it's more than likely to be an Italian shell*. Sounds an easy-peasy way of IDing Italian threading.

David

*"Oh, and one other thing - in this country they thread their fixed BB cups the wrong way round." </Charlie Croker> ;)
 
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