Originally Posted by
flintpond
I think I'm gonna go with the body change to hyperglide and put on a 7sp hyperglide cassette. After going with the hyperglide cassette, if I were to change a cog in the future, would I still have the same compatibility issues to deal with?
Yes and no.
Replacing uniglide cogs:
I really dont see that you have a compatibility issue right now. Its an easy fix, grab a 19t cog from wherever you can find one. It doesnt matter if its a 6, 7, or 8 speed cog and it doesnt matter if its uniglide or hyperglide. If its a hyperglide cog you'll need to file/dremel the wide hyperglide spline so it'll slide onto the uniglide body. A single hyperglide will slightly improve shifting quality into and out of the that particular cog.
Replacing hyperglide cogs:
Hyperglide cogs are designed to work with the cogs before and after. The cutoouts and tooth profiles are desgned to take advantage of the cog on each side of the one your shifting into and out of. Shimano letter codes each cog with a multiple letters like 'B-C-D' or 'E-F-G'. That means if your replacing a cog thats stamped 'E-F-G' your new cog should have 1 of those 3 letters but not all of them. What happens if you put a cog on that doesn have a matching letter? You lose a little shift quality becasue the cutouts and tooth profiles are no longer optimized. Heck, you can put a uniglide cog on if you wanted to with the only drawback being uniglide shift quality into and out of that particular gear.
Originally Posted by
flintpond
Yeah, I read that, but it looks as though one of the teeth(see pic) on my 19t is broken. If there's compatibility issues with just buying the 19t cog, I also saw a full ug cassette on loose screws for under $20.
You have broken teeth on more than the 19t!!!! Those are 'short' teeth designed to improve shifting performance. Back in the day we had at least 1 customer a week who'd come in complaining of a broken cog or worn out chainrings.