Weird Sprocket

[Smokin Joe]

First, a picture of my newly acquired fixed wheel bike -

Pretty little beast, if I say so myself. New bars to go on (Those in photo too narrow), new stem, clipless hoofs and a conventional brake lever. All well and good so far.

The fixed sprocket is the weirdest I've come across, the pitch is not standard and the chain rollers won't sit between the teeth, it just skates across the top. It is the same with the brand new KMC I bought today, as well as the one that came with the bike. In fact I've got to take the wheel to the LBS tomorrow to get the sprocket removed as my chain whip won't fit either and I haven't got a vice big enough to clamp it on to lever it off.

Anyone come across this before? The sprocket has never been used by the look of it and the freewheel on the other side is ok.

 

[Ian H]

It isn't just a narrow chain on an 1/8th sprocket, is it?

 

[Smokin Joe]

It isn't just a narrow chain on an 1/8th sprocket, is it?

Nope, 1/8" chain came with the bike and the same replacement was fitted today. The sprocket pitch is shorter than standard and whereas one roller will sit between the teeth the subsequent ones won't and get further out of kilter as it wraps round.

 

[Ian H]

Shimano made a track chain with a 10mm pitch. Don't think you can get it anymore.

 

[Smokin Joe]

Shimano made a track chain with a 10mm pitch. Don't think you can get it anymore.

I think I must have the matching sprocket.

 

[Ian H]

Perhaps if you ran it tight enough it would wear in.

 

[raleighnut]

Perhaps if you ran it tight enough it would wear in.

 

[midlife]

Shimano 10 stuff sells for stupid money....

 

[rogerzilla]

3/16" BMX sprocket?

 

[Smokin Joe]

Well at least I managed to get the bugger off this morning. The chain whip wouldn't wrap round it, but in the bottom of the tool box I found a large pipe wrench which gripped well enough to do the job.

Getting there slowly.