# 9 Speed Cassette on 7 Speed Hub?



## weltyed (Feb 6, 2004)

i feel embarrassed asking this question, but can i put a 9sp cassette on a 7sp wheel? The Wife has 1997 steel mtb and i am thinking of upgrading the drivetrain form a 3x7sp stx to a 1x9. if it is not possible, i might just find a newer 7sp rear mech.


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## Peanya (Jun 12, 2008)

IIRC, hubs changed when drivetrains went to 8sp.


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## Dave Hickey (Jan 27, 2002)

It depends....If you take off the 7 speed cassette and there is a 4mm spacer, yes it will work. If the 7 speed cassette does not have a spacer, no a 9 speed won't fit...

Many 7 speed geared bikes actually used 8/9 speed hubs.....Since hers is a 1997, you will probably be OK


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## rx-79g (Sep 14, 2010)

Unless you have the parts laying around, is this worthwhile? I'm betting you just want a simpler bike for her, since this one sounds very entry lever. Why not just stay with 7 and enjoy the benefits of cheap chains and cassettes?


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## Dave Hickey (Jan 27, 2002)

One additional comment....Any 7,8,9,10 speed Shimano(except Dura Ace 7400 series) RD will shift 7 speeds when connected to 7 speed shifters. They all have the same pull ratio...

That might be your cheapest option...


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## weltyed (Feb 6, 2004)

thanks, yall. im probably gonna have to take the wheel off just to check. i have a feeling there is no spacer. 

the drivetrain is original. i have a spare 7sp cassette, but will need to get a new chain. i really wanna throw a SS crankset on there. i will be able to run 9sp chainrings with a 7sp chain, right?

my original plan was to get me a sram 1:1 for my mtb and take my parts off and bolt them on hers. i even thought of building up a rear wheel as i am still running that bike as a mullet and have some nos disc calipers from when i built the front wheel and slapped a disc on there. if i did that the rear wheel is no problem as long as the frame is spaced correctly. its steel, so i could cold set if needed.

actually, the original original plan was to get her a flatbar 700C bike and turn her current bike into a SS (she never shifts anyway). but she doesnt really want one. and the ones i keep finding are AL, which is lighter, but im afraid she will not like the ride. every now and then i take her bike for a quick spin around the block and it is comfy. and i recall how more comfortable my steel mtb is than my AL. if she goes from steel fat tires to AL slimmer tires, i think i will hear nothing but complaints. so i think just upgrading the drivetrain and trying to teach her to shift might be a better option. afterall, she is ulling The Girl in teh cart while i have trail-a-bike duty with The Boy.


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## Dave Hickey (Jan 27, 2002)

weltyed said:


> the drivetrain is original. i have a spare 7sp cassette, but will need to get a new chain. i really wanna throw a SS crankset on there. i will be able to run 9sp chainrings with a 7sp chain, right?
> 
> .



No worries with 9 speed rings....


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## SystemShock (Jun 14, 2008)

Sheldon Brown had a trick called "8 of 9 on 7". You'd use 8 of the cogs from a 9-spd cassette, and one less spacer, of course.

Turns out that that pretty much perfectly fits into the space allowed by a 7-spd unit (at least with Shimanoo-compatible?). 
Cheap and clever way to upgrade to 8-spd.
.


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## ericm979 (Jun 26, 2005)

SystemShock said:


> Sheldon Brown had a trick called "8 of 9 on 7". You'd use 8 of the cogs from a 9-spd cassette, and one less spacer, of course.


You need the right kind of 7 speed hub for that, and you need the 7sp outer cog that screws on to the hub. But it works well, that's what I did on my Vitus.


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## PJ352 (Dec 5, 2007)

SystemShock said:


> Sheldon Brown had a trick called "8 of 9 on 7". You'd use 8 of the cogs from a 9-spd cassette, and one less spacer, of course.
> 
> Turns out that that pretty much perfectly fits into the space allowed by a 7-spd unit (at least with Shimanoo-compatible?).
> Cheap and clever way to upgrade to 8-spd.
> .


Here's the info:
http://www.sheldonbrown.com/k7.html#up7
Scroll down to *8 Of 9 On 7*.


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