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My knackered old pub/commute bike currently has some old shimano derailler on, indexed grip shifters and a 6 speed cassette.
The cassette is really too knackered now and needs replacing. In the box of spares I've got a partly worn 7 speed cassette, and it looks like there is room for it in the frame (bit of a gap between small cog and the frame where cog no 7 could fit).
But would the indexed shifters work with the change from 6 to 7 or not?
yes - spacing is the same up to 8, I think
Depends whether your 6-speed hub is Hyperglide compatible, i.e. can take a cassette with a lockring:
http://sheldonbrown.com/k7.html
Six-speed cassettes have a screw-on top cog, so the hubs don't always accommodate a lockring.
Also, cog spacing is different from 6- to 7-speed, so no, the indexing won't work:
http://sheldonbrown.com/cribsheet-spacing.html
SP - WRONG! 6 and 7 speed have different spacing, 8 is slightly different to 7 as well.
If the bike is from post 1989 or so it will have a block not a cassette, and a cassette won't go on the hub. If it's a 6 speed cassette it may have a threaded top cog meaning a modern 7 speed cassette won't fit either.
In short...pics?
Wow, more complex than I thought. Will post pics when I can.
I'm thinking of changing my username to exactly thatSP - WRONG!
Ah, my 1st mtb had 7 - see how young I am ? (the 7-8 sp diff was trivial though wasn't it ? I def used the wrong cassette on a bike for a while before I got new shifters with no problems)6 and 7 speed have different spacing, 8 is slightly different to 7 as well.
http://sheldonbrown.com/speeds.html
It's all in here.
If you have 6 speeds it won't be a cassette. it'll be a screw on freewheel. Just get another off these off ebay, they're common enough.
Yeah they did Uniglde which is different to Hyperglide. Then they did one that covered both. Then of course there was a 6 speed freewheel. Simples.
Deffo did 6 speed cassttes, though did they use it for MTB?
Yeah they did but I bet this isn't one.
If it IS and you can be bothered you could disassemble the two cassettes and use the sprockets from the 7 speed and the spacers from the 6 to build a new one.
Deffo did 6 speed cassttes, though did they use it for MTB?
Yep, 1987-88 Deore and Deore XT.
Yep, def did 6 spd cassettes. Got an nos one in shed 😉
I'm sure the STW family can rustle up some parts for you. I cant think many have the need for that (servicable) old cassette lying in the scrap heap. I can't help BTW
I'm going through this with a 1985 Ritchey Ascent. As I bought it, the freehub was locked up. The original 12-28 6 speed cassette was mangled, with bent and broken teeth. It was Uniglide (with the twisted teeth) not the newer Hyperglide with the shift ramps and teeth.
I had a Shimano 7 speed 12-28 cassette on hand. I took it apart and used a dremel tool to grind off the one wider spline that is used to index the cogs on a Hyperglide hub. I then used the 5 largest cogs along with the original 6 speed spacers (had to trim some little tabs off) and reinstalled on a new hub body. I bought a NOS Uniglide threaded small cog which holds everything together on the hub body. The 3 tiny bolts that hold the cassette together are just for convenience, and aren't really needed.
So its now 5 Hyperglide and 1 Uniglide cogs. Will try it on the bike today or tomorrow.
HTH.
I mounted the 5 HG +1 UG cassette and it works just fine.
OP - I suspect that the biggest problem that you will come across is removing the threaded cog from your current cassette if it doesn't use a lock ring like current ones. Since the threaded cog has a right hand thread, the chain acts to tighten it every time that you pedal in that gear. Add to this years + water + dirt and they can be almost impossible to remove!
top tip for removing stuck freewheel. Put the freewheel tool in the wheel, then clamp the tool also in the vice. Turn the wheel around the stationary tool = lots of leverage!
ps don't forget to turn the right way, otherwise you won't get anywhere!
Wow, this takes me back to 1990-91 when I was using the old 6-speed screw-on Hyperglide freewheels with 6-speed indexed shifters for cheap, quality shifting. The Cannondale with that set-up got nicked 🙁
6-speed hyperglide screw-ons existed in 1991? IIRC they were all UG.
6-speed was bomb-proof though.
I did this,but was using non indexed downtube levers.
6-speed hyperglide screw-ons existed in 1991? IIRC they were all UG.
6-speed was bomb-proof though.
Yeah, I was surprised when I looked into it at the time. These days, I consider 8-speed to be largely bomb-proof and will not upgrade until I absolutely have to.