Hi there. I am so desperately confused and I need help. I have a 1985 Fuji Allegro (pic attached) that I would like to convert into a single speed. This is my first time doing this. After perusing the forum and consulting Sheldon Brown, I figured that all I would really need to do is remove a chainring and replace the cassette with a BMX freewheel, using some spacers to get a correct chainline. I was hoping I could get this done for under $50.

I went down to my local bike shop and the guy said it would cost me $300, or $250 if I did the work myself. He said my back wheel needs to be replaced because just replacing just the freewheel would cause an incorrect chainline. This price seems absurd, and there's no way I'm putting that type of cash into a $25 garage sale bike.

Anyway, now I'm really confused. How much would this project cost me? What would I need to do/buy to make this a single speed?

Thanks very much!

Here you go:

https://www.cicle.org/wordpress/2007/...-conversion-2/

Wonderful link there Ben, I didn't know about the washers! I've been stalling on my own version of this project as well, mostly held up by the fact I haven't ordered my freewheel tool yet. OP, that link will simplify it all for ya!

If that's a 10 speed, you can swap out the current freewheel with an ISO-tread single speed freewheel. The wheel isn't dished for gearing, so the chainline should be almost perfect to run on the inner chainring. The rest of the work is just Definitely nowhere near $250. You can use the current derailleur as a chain tensioner, or get a purpose-built one cheap.

This is very informative. Thanks!

It's actually a 12-speed. Does that make a difference?

Maybe.

To keep the axle from getting too long, the wheel is dished inwards on the right side to leave more room for the gears. If you look at your spokes, you'll notice that the ones on the right side are at a much steeper angle than the ones on the left. This means the freewheel threading is too far to the left relative to your chainrings, although with a 6 speed you should have a good chainline going from a single speed freewheel to the inner chainring without having to mess with spacers. An SS freewheel's cogs will be about where 2nd gear is on your current freewheel.

However, I would NOT file the dropouts to increase chain tension as suggested in the article.

You may also find this thread helpful:
https://www.bikeforums.net/showthread...bikes-to-SS-FG