bottom bracket questions
 

hey, i need a new BB for my '79 peugeot, and wanted to know if i got this french thread cup set from amazon and this spindle from ebay if i could use them together. thank you very much
http://www.amazon.com/gp/product/B00...GMKCNZ2TN08CEE

http://cgi.ebay.com/RITCHEY-BOTTOM-B...#ht_2072wt_698

I thought it would be tough, but this one is easy.

Those two are definitely not a match. The cups are for a loose ball bottom bracket, and the spindle for a cartridge bearing bottom bracket.

The cups will work, but before buying them ask the seller if he has a matching spindle for your bike.

But before you even call, you need to know whether your cranks are steel cotter pin cranks, or aluminum cotterless cranks that take a square taper spindle. Once you know what kind of spindle you need, you need to know the length (over all length).

Once you have the spindle spec'd then you need compatible french thread cups to match.

okay. thank you for that information. i will need a square taper spindle. if you could tell me what kind of spindle i would need to fit those cups that would be great

You're doing it backwards.

You know that you need French thread cups, so you start by measuring your existing spindle to find out what spindle you need, then you get French cups to match that spindle.

Work form the harder to spec part to the easier one.

well the thing is i need new cranks as well. and i actually have a set that fit on 107mm spindles. could i just replace the whole crank and BB with new parts that are meant to fit each other? or would i need a specific length to fit through the BB tube on my bike?

If you have the cranks, and a matching BB or at least the spindle, give it a shot. Most bikes are fairly close to each other in terms of BB width and chainstay clearance.

Unfortunately, since the crank offset varies, just knowing the spindle length isn't enough. You could assemble the right crank onto the spindle with a cup, and start measuring where it'll end up, but by that time it's just as easy to install and see if it's OK. If not, you'll know how much longer or shorter a spindle you need.