Bottom bracket sizing?
 

Hello all you wise wonders !

http://img30.imageshack.us/img30/3476/mar002.jpg

I have a Maruishi 202 road ace.

http://img194.imageshack.us/img194/9356/mar001e.jpg

I want to convert it to a single speed, get a more appropriate single speed crankset.
Yet don't know what the bottom bracket size
I've been to the bible, yet don't quite understand what i am supposed to be looking for.
http://sheldonbrown.com/gloss_bo-z.html#bottom

You need English threading. The BB size (width) with be dependent on the crankset.

Chain line questions like this have puzzled me as well, and I too have read Sheldon's without gaining much wisdom. The BB length will definitely be shorter than the one for your double. I would suggest posting on the mechanics forum, I've gotten great realtime advice there.

I hate to correct a esteemed fellow C&Ver but you need a an english threaded BB and the spindle length will depend on the crankset you wil use, not your BB width.

hen you purchase a new crankset check the specs and see what length spindle you need

OFG and BG are both correct in saying that BB spindle width is determined by the crankset used.

However, with a less than ideal BB width, it is possible to correct chainline by means of hub spacers on the rear axle. The key is to use a crank spindle narrow enough to allow the freewheel to adequately clear the dropout. After that, in/out alignment can be made
with the spacers.

I was trying to not get too technical with a newbee, obviously the bb width will be 68 on a road bike. My apologies.

Thank you everyone... for replying.

I don't think it's going to be something, that I can understand without a little more experience.
At the moment it's all just gobbledygook. Bike stores and the people who run them are great and all.
But if you want to do something inexpensively... and you don't have the knowledge,
there isn't a lot of options out there. Bike sizing is a mine field of different scales and formats.