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PostPosted: Sat Jan 19, 2013 3:18 pm 
retrobike rider / Gold Trader
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Is it possible to make an 8speed cassette 9speed?

I've got an m737 XT cassette, which would be nice to make into a 9sp. The smallest cogs are 11 and 13t, would it be a simple case of adding a 12t inbetween them? Or would I need a complete set of lower cogs, due to spacing on the freehub?

Or should I just forget it as its not even possible??

Cheers for any help


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PostPosted: Sat Jan 19, 2013 3:20 pm 
Retro Guru

Joined: Tue Jun 05, 2012 8:04 pm
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I may be wrong but if i remember rightly the spacing and chain are different from 8speed to 9speed.


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PostPosted: Sat Jan 19, 2013 3:28 pm 
retrobike rider / Gold Trader
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Makes sense, but thought I'd ask before I sourced a 9sp cassette..


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PostPosted: Sat Jan 19, 2013 3:43 pm 
Gold Trader / rb Rider / Special
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Yeah as above. I think yours is on a spider? If not maybe you could change all the spacers too?


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PostPosted: Sat Jan 19, 2013 3:56 pm 
retrobike rider
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You can of course, like we used to make 8spd from 7spd BiTD with a screw in bottom cog.

The stumbling point would be shifters at 8 speed spacing with an extra 9th click as each cog is that little bit closer together, as you guessed it, to get it to fit on.
It's actually a much larger decrease in cog to cog than there was from 7 to 8 speed.
(almost half a mil.)

To be honest, given the number of 9 speeds available it's a pointless exercise


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PostPosted: Sat Jan 19, 2013 5:53 pm 
Old School Grand Master
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8 and 9 speed cassettes are the same width which means the cogs are closer together.

if your 8 speed cassette is made up of individual cogs and spacers, then using thinner spacers from a 9 speed may work assuming the thickness of the cogs is the same which I doubt.

plonking on another cog means the cassette is wider than the freehub so you will not be able to screw on the small cog.


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PostPosted: Tue Jan 22, 2013 10:43 am 
BoTM Winner
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Joined: Thu Jan 19, 2006 1:23 pm
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If you fancy selling the 8 speed to fund a new 9 speed them pm me with condition and price.
Cheers,
Steve T.


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PostPosted: Tue Jan 22, 2013 1:25 pm 
Gold Trader / rb Rider / Special
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02gf74 wrote:
if your 8 speed cassette is made up of individual cogs and spacers, then using thinner spacers from a 9 speed may work assuming the thickness of the cogs is the same which I doubt.


A 9 speed chain will work fine on 8 speed sprockets.


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PostPosted: Tue Jan 22, 2013 1:25 pm 
Gold Trader / rb Rider / Special
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02gf74 wrote:
if your 8 speed cassette is made up of individual cogs and spacers, then using thinner spacers from a 9 speed may work assuming the thickness of the cogs is the same which I doubt.


A 9 speed chain will work fine on 8 speed sprockets.


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PostPosted: Tue Jan 22, 2013 5:55 pm 
King of the Skip Monkeys
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And theres me thinking you actually knew what you were doing.

Tut.

Try SRAM 9spd cassettes - very light and some come with alu spiders


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