Cassette Query

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pubrunner
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Joined: 22 Jan 2009, 8:29pm

Cassette Query

Postby pubrunner » 10 Jun 2011, 4:21pm

Hi All,

One of my bikes has some Wolber Profil wheels that I rather like.

However, I could do with replacing the cassette which is 6 speed - I'd like one which is slightly lower geared - 30, rather than 26T.

Probably a 'daft' question, but will there be any 7 speed cassette that I could replace it with ?

What viable options are there ? - Without having the wheel re-built ?

(It is a cassette, not a freewheel)

Out of interest, can cassettes be 'moved up' a size ? ie, 7 to replace a 6 speed; or 8 to replace a 7 speed ?

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Mick F
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Location: Tamar Valley, Cornwall

Re: Cassette Query

Postby Mick F » 10 Jun 2011, 4:43pm

6sp cassette?
I wasn't aware they ever existed.

No doubt this is Shimano, so I'm not best placed to advise, but basically you can upgrade cassettes by buying the complete thing - cogs and spacers. All you have to worry about are two things:
1. Splines system that allows different cog sets.
2. Width. Some cassettes are wider than others.

Basically, can you state exactly what you have now?
Mick F. Cornwall

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531colin
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Location: North Yorkshire

Re: Cassette Query

Postby 531colin » 10 Jun 2011, 6:57pm

It might be Shimano "uniglide".....this is in my mind due to all the help I got here...http://forum.ctc.org.uk/viewtopic.php?f=1&t=51995
I think a 7 speed cassette will be wider than a 6, so you may not be able to get more gears....if you can measure your 6 speed reasonably accurately.....
my 7 speed uniglide is 32mm according to my vernier

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gaz
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Location: Kent, lorry park of England

Re: Cassette Query

Postby gaz » 10 Jun 2011, 7:00pm

Mick F wrote:No doubt this is Shimano,

Speaks a man who clearly doesn't remember Suntour. :wink:

If it's Shimano then you'll have a real hen's teeth mission to find a 6 speed cassette, if it's Suntour it won't be so easy.

If it is Shimano then it may be possible to change the "freewheel" part of the hub to a 7 compatible part (await advice from others, I'm still on proper freewheels). At a guess 6 speed will be 126mm OLN, and I'd expect you'll need at least 130mm to run 7 or upward, new axle and additional spacers. You may get away with 130mm without cold setting the frame.

I believe 7 is also pretty much obsolete and you'll be relying on new old stock.

It may be time to think 8.
There'll be tarmac over, the white cliffs of Dover ...

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Mick F
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Re: Cassette Query

Postby Mick F » 10 Jun 2011, 9:15pm

Mick F wrote:No doubt this is Shimano,
gaz wrote:Speaks a man who clearly doesn't remember Suntour. :wink:

I remember Suntour very well indeed thank you very much! I still have many of the bits.

Trouble is, Suntour was a freewheel block with interchangeable sprockets, not a cassette, but no doubt there could be cassettes out there as they modernised and were bought out by Sh - you know who.
Mick F. Cornwall

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gaz
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Re: Cassette Query

Postby gaz » 10 Jun 2011, 10:07pm

Mick F wrote:I remember Suntour very well indeed thank you very much!


Not that well, you've forgotten Suntour cassette hubs which were not Shimano compatible.

Please don't ask me any Campag related questions. :wink:
There'll be tarmac over, the white cliffs of Dover ...

oldnick
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Joined: 26 Mar 2011, 4:14pm

Re: Cassette Query

Postby oldnick » 20 Jun 2011, 7:46pm

You can replace a six with a seven if it's uniglide, I've just done exactly that. You can get the cassette here:
http://www.sjscycles.co.uk/shimano-6400 ... rc=froogle
I found the spacer on the sprocket one up from the threaded sprocket was 3.6mm instead of the 3.1mm of all the others. I've no idea why because Sheldon Brown states 6 speed should be 3.65 and 7 3.1. Either way, I just sanded the spacer until it measured 3.1 and put the cassette on the old uniglide hub. It is a tight fit but it did go on. I needed one spacer washer on each side for the chain to clear the cast alloy nut the fits on the inside of the dropout and takes a bolt going through the derailleur mount (mine uses the hub spindle nut to hold it in place).
It works fine but I've got friction shifters, not sure if it would work with indexed.