What's the easiest way to know what BB threading?

[Buffalo Dude]

I bought a road bike with a mish-mash of parts, how do I know what BB threading I have? The frame predates the internet, so I can't google it. Right now it has a Shimano Deore XT crank, and I want to change it to something a little more modern (and not off a mountain bike ). Should I just take it to a shop and have them tell me or is there a way to easily identify it?

 

[bobbyOCR]

I bought a road bike with a mish-mash of parts, how do I know what BB threading I have? The frame predates the internet, so I can't google it. Right now it has a Shimano Deore XT crank, and I want to change it to something a little more modern (and not off a mountain bike ). Should I just take it to a shop and have them tell me or is there a way to easily identify it?

How old does the Deore look? any photos. It is almost a definite English threading as most cranks are/were, especially shimano.. To find the width, just use a tape measure.

 

[CAMPYBOB]

your fixed cup may be marked with threading information.

 

[hd reynolds]

Width of the BB is the determining factor - 68mm English, 70mm Italian.
For spindle length, just get the spindle that goes with the crank you're replacing it with.

 

[Buffalo Dude]

Does this mean anything to anyone? And why would someone put mtb parts on a road bike?

 

[hd reynolds]

Does this mean anything to anyone? And why would someone put mtb parts on a road bike?

1992 Shimano Deore LX crankset.
Came with either BB-M550 or VV-UN51 bottom bracket.

And why would someone put mtb parts on a road bike?

Possibly because he wants a lower gear triple.

 

[DMF]

Doesn't mean anything in the way of threading; that's a BB issue. Chances are good, though, that it's English.

 

[Insaneclimber]

I bought a road bike with a mish-mash of parts, how do I know what BB threading I have? The frame predates the internet, so I can't google it. Right now it has a Shimano Deore XT crank, and I want to change it to something a little more modern (and not off a mountain bike ). Should I just take it to a shop and have them tell me or is there a way to easily identify it?

http://www.sheldonbrown.com/gloss_bo-z.html

This web page gives all the info that your after, but id say that it will be the english thread as its the most common. And thats not realy a mtb crank set its just a cheap set.

 

[Buffalo Dude]

Thanks everyone

And thats not realy a mtb crank set its just a cheap set.

Shimano still lists the Deore LX as mountain bike parts. Was this just a cheap part back in the day?

 

[drubie]

Does this mean anything to anyone? And why would someone put mtb parts on a road bike?

MTB parts are easier and cheaper to get in 8 speed variants if you want to patch up an old road bike. I had an Alivio (or something) 8 speed rear der. on my road bike after I snapped the Mirage one. It worked surprisingly well with the campy levers.

Most of the bottom brackets have some markings or serial numbers on them (not the crank as in the picture, but the bottom bracket itself). Try getting a picture of that.

cheers,

dave.