Hi guys,

I have a 564 circa 1990. I just replaced the chain(original) and now it's skipping on the 19t cog. I read these cassettes aren't available anymore.

1) can I find a replacement cog?

2) is there a 7sp cassette that will fit on the existing rear wheel(stock)?

Any info will be appreciated.

I'm not sure what your information source is or why they're saying the Shimano 7-speed cassettes are no longer available, but they are. Your 564 has a Shimano 7-speed cassette with 13-14-15-17-19-21-23T.

Go HERE and order CS732 for $29.95.

Hmmm....I have a stock 564 and my cassette is 13-25. I also think it may be a Uniglide and not a Hyperglide like the ones for sale at Harris. If so, a hyperglide freehub body would have to be installed on your wheel to use a hyperglide cassette.

1989 Schwinn Lightweight Specifications.

Hmmm. It says here the 564 came with a 13-14-15-17-19-21-23T cassette (it wasn't beyond Schwinn to substitute). My 1987 Paramount with Dura-Ace 7400 7-speed is Hyperglide, so I assumed the '89 and later 564 would be Hyperglide. I see the '89 specs call for a Uniglide chain, so my assumption could be wrong. He could still use a Hyperglide cassette by changing to a Hyperglide ratchet body as you suggest and as Sheldon Brown explains ON THIS PAGE. It's an easy and inepensive modification.

You guys are making me work tonight.

The Repair Parts page for the 564 shows the freewheel as a Shimano CS 1000 7-speed cassette 13-26 with the part number, 27-401, marked with an asterisk which indicates a substitution from the original spec'd part.

Looking at the Shimano freewheels page in the Parts & Accessories catalog, part number 27 401 is a 13-26 7-speed 600EX (Ultegra) cassette. which is, indeed, Uniglide. So, to use one of the Hyperglide cassettes, the freehub ratchet body would have to be changed. It's an easy and inexpensive mod.

Do you have a close up picture of the cassette? This would solve the confusion.

This is a pic of my cassette. notice the third largest cog, 19t, which is the problem one. tooth in 12 o'clock position looks broken. I only noticed this skipping when I changed the chain.

It looks like uniglide. If I am on track, this means I can swap out the body for a hyperglide, and then use a seven speed hg cassette. Would loose threads be the best place to buy?

You can buy individual Uniglide cogs from Euro-Asia Imports in California. If the problem is just with the 19t cog, you can replace just that cog on the cassette; you wouldn't need to change the hub. To ensure you get exactly the right cog (thickness and spline pattern), you may want to take your bike to a LBS and have them disassemble the cassette to determine the correct 19t cog you need and replace it on the hub and reassemble it.

I think I'm gonna go with the body change to hyperglide and put on a 7sp hyperglide cassette. this will keep me from worrying about other cog issues for a while.

The Harris Cyclery part # for the freehub body shows as CS015. I would then use a CS733 cassette. Is this correct?

I thank you for the help. I didn't realize there were so many compatibility issues. I'm gonna do the change myself, as I'm an aspiring weekend mechanic.

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?

Stupid bike tricks. You can get more miles out of a worn twist-tooth cog by turning them around. Remove the cassette, disassemble, either by undoing the screws that hold it together or knocking apart the rivets and slide them back together with the cogs flipped over.

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.

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.



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.

What about thickness and spline pattern of the uniglide 19t cog replacement? I'm not concerned with ultra smooth shifting, but would want it to fit...

As long as its not an IG cog thickness isnt an issue. If its a HG cog all you need to do is grind a little off the wide spline.

I have a silver 19t hyperglide cog you can have for free. If you want it I'll grind down the wide spline for you.

PM me your mailing info if you'd like it.

Jim