9 into 7 won't go.....

[neilob]

I am building a tough stuff tourer using a 1990s steel MTB frame and some parts plus bits from my stupidly large spares box. The wheels originally had a 7 speed cassette but the shifters I want to use are 9 speed. Although the 9 speed cassette body goes on to the freehub it isn't deep enough to allow the smallest cog to fit. However if I remove this cog I can then lock the cassette properly albeit as an 8 speed with 9 speed spacing. So providing I lock out the rear mech at the top end I am assuming it will work ok?

[ElCani]

It will. My partner’s bike is running exactly that set up.

[Tompsk]

Ditto, 9 of a 10 on a 7 works well too. See Sheldon Brown pages on this topic.

[fastpedaller]

AIUI the criteria are:-
the gap between sprockets needs to match the shifter - as long as you've used 9s spacers that will be correct.
The total width has to 'match' the cassette body (this can be achieve by using thinner spacers to arrive at the 'target width')
the high/low limit screws need adjusting as necessary.
there will be redundant shift position(s) on the shifter- no problem.
I altered one of my bikes (a Montague Rudge folder) using 5 of a 7 cassette with spacers to achieve a similar objective.

[The utility cyclist]

I filed back the meat on the alloy freehub body of my carbon tubs to fit 11 speed cassette, probably not worth doing it for this set up but would think there's more tolerance on a 7 speed wheel than mine.

[NickJP]

I have that exact setup on one bike where I used an NOS 7-speed Deore DX rear hub. I discarded the 11t cog from a Shimano 11-32 9s cassette, and that gave me a 12-32 that fitted on a 7s freehub. I also needed to use 12t lockring instead of the 11t lockring. And another advantage of that setup is that with a rear rim with offset spoke holes (which can just be seen in the photo below), the 135mm OLN rear wheel is essentially dishless. Here's the setup in question:

[mattsccm]

I have done the same as the Utilitycyclist on half a dozen wheels to fit 11 on to 10 so why not do the same, especially if its nearly there? Is it a 7 speed free hub? If not why not bung on an 8 and up speed freehub? I know that, in theory, there are many versions etc but in practice if you raid a free hub from something like an old 8 speed MTb hub you will find it drops on. Try your local bike shop for knackered wheels.

[Brucey]

I am building a tough stuff tourer using a 1990s steel MTB frame and some parts plus bits from my stupidly large spares box. The wheels originally had a 7 speed cassette but the shifters I want to use are 9 speed. Although the 9 speed cassette body goes on to the freehub it isn't deep enough to allow the smallest cog to fit. However if I remove this cog I can then lock the cassette properly albeit as an 8 speed with 9 speed spacing. So providing I lock out the rear mech at the top end I am assuming it will work ok?

yes of course. If you search for '8 from 9' or similar you will find many mentions I expect.

There are a few wrinkles concerning the smallest sprocket though; there are at least three different types of 7s freehub and the same top sprockets don't work with all of them. If there is a problem it is one that can be solved though.

I personally like (actually prefer) this setup because I have very little use for an 11T top sprocket anyway, and the wheel has a far better dish with one sprocket less.

cheers

[MtbTourer]

I have that exact setup on one bike where I used an NOS 7-speed Deore DX rear hub. I discarded the 11t cog from a Shimano 11-32 9s cassette, and that gave me a 12-32 that fitted on a 7s freehub. I also needed to use 12t lockring instead of the 11t lockring. And another advantage of that setup is that with a rear rim with offset spoke holes (which can just be seen in the photo below), the 135mm OLN rear wheel is essentially dishless.

Hi Nick,

I'm preparing to do the exact same thing with an CS-M770 11-32t cassette. Is that the cassette that you used?

There are 2 things I would like to check though.

Will an Ultegra CS-6700 10-speed 12t Lockring be compatible?

With the 11t cog removed from a CS-M770 11-34t cassette, my Vernier Caliper indicates an Overhang of about 1.2 mm for the 13t cog. Is that enough to properly engage the Lockring? How much Overhang was there for you with the 12t cog?

Thanks!

[NickJP]

I'm preparing to do the exact same thing with an CS-M770 11-32t cassette. Is that the cassette that you used?

There are 2 things I would like to check though.

Will an Ultegra CS-6700 10-speed 12t Lockring be compatible?

With the 11t cog removed from a CS-M770 11-34t cassette, my Vernier Caliper indicates an Overhang of about 1.2 mm for the 13t cog. Is that enough to properly engage the Lockring? How much Overhang was there for you with the 12t cog?

The cassette I used was a Deore HG-50 11-32. It has serrations on both the 11t and 12t cogs, so if you don't fit the 11t the lockring still has serrations to grip onto on the 12t cog.

My rule of thumb is that three threads should be engaged. If the lockring turns three times once the threads engage before you have it tight, that should be enough. If you're worried about it, use a lower level steel lockring, rather than the Ultegra one, which is aluminium.

Can't tell you how much overhang there was. There has to be some, or the lockring will bottom on the freehub body before tightening on the cassette.