I got this bike from craigs list owner had put this crank in it, I'm wanting to make this a singlespeed . ill be upgrading to 700c wheels and want a crank with one sprocket. any recommendations? thanks in advance this is an ols 1978 Schwinn

shirefolkbike, You'll want a crank or a single chain ring that has no shifting aids (ramps and pins) meant for a single speed. Determine the BCD of your crank arm's spider to find a chain ring. You can use the chain ring on the inside and a trouser guard at the big ring's location

Brad

To expand on the above post - You can use the cranks you have, just need to get a chainring and bashguard. BCD refers to the diameter of the mounting bolts for the chainrings, needed to find a compatible ring How to measure Bolt Circle Diameter (BCD). Once you have the BCD just search for a chainring with that BCD and the tooth count you need, plus a trouser/bashguard.

What's wrong with the current crank? You could just leave the chain on one ring all the time, or remove one ring and use BMX chainring bolts to hold the remaining ring in place. If you prefer a different tooth count than what you currently have, you just need to match the bolt-circle diameter of your crank (your picture is too small for me to identify your crank, but I'd guess perhaps a Shimano with 130mm bolt-circle diameter; post a better picture if you want a positive identification). As mentioned above, avoid modern rings intended for multiple chainring installations, as these have ramps and pins to facilitate derailment; not something you want on a single ring set-up. There are modern rings intended for single ring installation, and your bike appears to pre-date ramped and pinned rings, so the current rings are unlikely to have these features.

heres the crank that came on bike. I just want to eliminate the bigger sprocket. on the outside

Then just get a "chainring guard," probably 130mm BCD, to install in place of the outside ring - done. Although ideally you would install a plain chainring in place of the ramped/pinned one in the middle, it's not necessary.

thanks for the chain ring guard idea