using a cog from a casette as a sprocket

i stumbled across this on ebay:

Campagnolo 17 Tooth cog - fixie project (eBay item 140499310820 end time 17-Jan-11 22:16:16 AEDST) : Sport

it’s a 17T cog taken from a larger casette. it happily states “Suit any fixie project.” could this actually be used as a single sprocket? or would there be problems fitting it on/abnormally fast wear?

it could be used for a single speed using a cassette hub, you couldn’t use it fixed without some skillz or uncommon hubs.

fixed that for you

took me a while to get that one

or welding up a campag freehub so it doesn’t freewheel anymore, which would be dumb.

I’m going to try to be helpful here:

Sprockets from modern cassettes (like the ripper little bargain above) are designed so that the chain will slip off them fairly easily. That’s why the tooth profiles are shallow and the sprocket faces are ramped, both to make shifting easier. This is rather the opposite of what you want in a fixed-wheel drivetrain - you want a deep tooth profile and no fancy ramping so the chain stays on your sprocket as best it can (with appropriate chain tension and chain line etc etc). The same pretty much for SS applications - a specific SS sprocket is best but you can kind of get away with using a cassette sprocket and a few spacers on a cassette freehub if the sprocket’s not too worn and your chain tension and chain line is good.

Here endeth the lesson.

And…if you wanted a Campag freehub singlespeed, Gusset make ss cogs with Campag splines that would be a better option.

Listen to Snowflake. Campag splined SS sprockets didn’t exist until Gusset made them. Don’t use a cassette sprocket, it’ll throw the chain all the time.

And if you have a shimano/SRAM splined hub, then that sprocket being sold won’t fit anyway.

And it’ll probably quickly chew the shit out of your freehub body as a nice bonus seeing as it cant spread the load across little more than 1mm of metal.

One of the reasons the Gusset cogs are good is because the footprint is 10mm wide.