Brian_T

Sheldon Brown has an awesome article on Fixed Gear conversions. Here’s a direct quote:

"I usually check the chainline by installing the hub in the bike, with no chain installed. By placing my head just in front of the chain wheel, I can sight along the chainwheel and see back to the rear hub, to see if the chainwheel lines up exactly with the rear sprocket. If it doesn't, I re-arrange spacers or change the bottom bracket axle as necessary.

Usually, on a bike that came with double chainwheels, the inner chainwheel will be more in line with the rear sprocket. If you wish to make the bike a pure fixed gear, you can buy a set of shorter "stack bolts" (the 5 bolts that hold the chainwheel(s) to the crank spider). You may find it easier to locate these in a shop that deals in BMX bikes."

Please review Sheldon’s article in its entirety at:

http://www.sheldonbrown.com/fixed-conversion.html