this, at least until well-worn. also some threading issue as i recall...loose on some hubs? foggy recollection.

otherwise, solid work-a-day cogs. the eai black is barely more expensive and a helluva lot nicer. no silver though...if you're into that.

I had a Surly cog once. Machined badly. Very noisy and lots of grinding. Deep sixed it. Now it's nothing but Dura Ace up to 16T and Soma for anything larger. Cheaper actually.

After messing around a little, I was able to find some weird areas in the rotations. Here are two pics where the chain looks kinda funky on the cog. Any ideas?




The chain kind of sticks and bends up in a weird way - almost like a stiff link, but the link is not stiff. Either way its causing the wheel to not spin freely, and kind of jumping and slowing down the rotation.

Like I said, Surly cogs are machined wrong. Deep six the dang thing and get a good cog like Dura Ace. Heck, even a $16 Scrod cog would be better.

It ran fine with my KMC Kool, which is why I'm concerned. Bleh. Guess I wont go Surly again

It's because Surly cogs have those big dumb square teeth.

Thats what the master link or quick pin link is for, And if you do it right, Nothing happens.

I was looking at the scrod cog. What exactly is the difference? Looks kinda just like the Surly. And I'd love a DA cog, but they only go to 16t, and I need 17.

Why don't you PM Scrod ? I'm sure he can tell you. Also, Somas go from 17 to 21 teeth, and are great cogs as well.

Ok, great. Thanks for the advice everyone.

Arent surly's cogs a little taller then the average to prevent dechain

That would make sense as to why my chain isnt wanting to "let go" so to speak, causing a bit off an off rotation.

them's fightin words...

Im glad I found this thread. Ive been running a 18T surly cog/sram pc-1 combo for years with no noise issues. I recently switched to wipperman chain and now I get a ton of chain noise off the rear cog. I didnt even think about the cog. If I flip the bike over and spin the cranks, you can tell that the noise is coming from the rear.

I can tell you that surly cogs are quiet with SRAM chains. Dont throw out the surly cogs, just run a PC-1 with it. If you have wipperman expect noise. The wipperman side plates are much larger than the PC-1 I guess that is why its noisy with the square teeth....

On another note, my surly 18 tooth cog has squared off teeth, my 19T surly is more pointy - go figure.... Might take a dremel to round off the corners of the square tooth. My Euro asia 17t has pointy teeth too..

Well I took a grinding wheel to the sharp corners of the squared off surly teeth and I think I did the trick. The cog is smoother with the chain. I finished off the sharp edges with a file to smooth them out. Sorry for the grainy pic.

You should expect some noise any time you put a new chain on a used cog.

bang. last reply hit it.
look...work your own diagnostics, but...

you need to make sure its not a chain link.
otherwise, your components may not match. in other words, chains stretch and cogs/chainrings wear. if they aren't matching, it may take some time to mesh...or if its bad enough, it just won't work

we're so glad you're back.