Shimano Hyperglide Cassette 7 sp

chickendrumsticks

Senior Retro Guru
Hi all

I want to change my 7 speed 13-26 version to a 12-21 (or 12-24 if necessary). The only info I have is that the cassette is described in the catalogue as "Hyperglide" and it's about 1990 vintage. My LBS could only offer a new body(?) and cassette which was too pricey. If anyone has a suitable cassette for a reasonable price I'd be interested.

Any advice welcome - I have glanced at Sheldon Brown's site but came away more confused! It's me age...

I wonder if a CS-HG50 (13-21) would be a direct replacement? They seem to be available widely.

Thanks in anticipation.
 
Do you want the original part, or just a 7 speed cassette in that ratio? If you just want a 7 speed cassette then there are still plenty to choose from. If you can't find a 12-21 then you can mix and match between two cassettes to get the 7 sprockets that you want.
 
The lower end cassettes have the 6 largest sprockets riveted together, you can dremel or drill out the rivets to separate them. The higher end cassettes have the sprockets bolted together, you just need to take the long bolts out and they all come apart.
 
Re:

Yeah, thanks again. Upon closer inspection I can see 9 evenly spaced splines, which I think means it's a Uniglide rather than a Hyperglide - whatever the catalogue says. And I think if the smallest sprocket is unscrewed it means that the next six are just sitting on the splines with spacers in between and can be pulled off? The outer (smallest) one bears the markings "8-BC34.6" and what looks like Shimano's date mark for Dec '89 (NL) which matches the bike's age.
 
If the hub / body only has threads on the out side where the smallest cogs screws on then its a Uniglide, if it has threads on the inside then its a Hyperglide.

This is the case with both 105 and 600 from this time period, if its a Dura Ace hub then the 1st two sprockets are unique I believe.
 
k7hub-3-stylessm.jpg


Sheldon has a good picture (above)

Shaun
 
Re:

If it is UG you need, then they are now hard to find. If it is Dura Ace UG, then even harder. It is only the screw-on smallest sprocket that is different with Dura Ace -- smaller diameter to allow 11sp.
It is possible to file down HG sprockets, though I haven't tried it myself. See http://cycleseven.org/fitting-hyperglid ... de-freehub, for example. I agree with their statement that the metal is pretty soft, and you already have the plastic spacers...

Nick
 
Thanks to all who have taken the time and trouble to help. I'm now pretty sure that I have a UG due to the 9 evenly spaced splines...Now I think all I need is two UG sprockets - a 22T and a 24T - which I should imagine someone must have lurking in their spares box? That's if I'm right in thinking that once the outer "lock-ring" small sprocket is removed the 6 remaining can be pulled off? Can someone confirm this please? And if they can, are they bolted or riveted together (as described by Foz above) or are they loose (with spacers obviously)? Thanks again, all.
 
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