Mountain Bike Parts

crank size for my road bike bicycle.?

i am making my old road bike into a singlespeed. i have the wheels set up and everything but i realize the original crak (a really old three piece) had too many teeth (52) so i took it off in the hopes i could but i different one on. i have an old BMX bike lying around so i wanted to use its DK crank but it was too big, the bearring were too big and i could even get the one piece crank part to fit through the BB hole in my bike. can someone explain the different sizes and maybe suggest the one i need. thanks!

There are two major bottom bracket sizes used on bikes. BMX (one piece) and Road (also used on Mtbs). Road is further separated into two different widths (68mm and 73mm). There are also three different types of threading (Italian, English (somethings called BSA) and an older French threading (this is pretty rare). Most likely you need English thread in a 68mm width. This is a great crank:

http://www.velo-orange.com/suxdtrcrhipo.html

Here’s the BB you’ll probably need: 68 x 107

http://www.velo-orange.com/suxdtrcrhipo.html

Check with your local bike shop to figure out the exact size BB you’ll need.