I’m messing around with an old bike I’m trying to figure out how to take this bolt out. It threaded on one end and there’s nothing on the other end to un screw it? It’s a really old bike and the current front cog doesn’t fit a regular chain so I want to try and replace it with one off a different bike.
by Fun-Opening-7977
3 Comments
Here’s a page with instructions: https://www.sheldonbrown.com/cotters.html
It may be hard to get a replacement to work with that crank arm or bottom bracket.
Yes, it looks like a cottered crank. However, I am surprised that a new chain does not fit. Which dimension of the chain does not fit? Have you tried a single speed chain?
That’s called a cotter, sometimes called a “cotter pin”, even though there is no pin in the cotter.
the best way is with a lot of heat from a blowtorch on the crank arm, so it expands and releases the pin. Then you can knock it out.
But I have to caution you, there is a good chance that this chainwheel actually does fit a regular chain, it looks like standard half inch spacing between teeth. Likely you have tried a thin chain from a modern bike that has derailleurs, you want a wide chain for a bike that doesn’t have derailleurs. Look for “single speed chain”, “1/8th chain”, whatever.