9 speed chainset with 7/8 speed gears

[e-rider]

so, I know that a 9 speed rear mech can work perfectly well with 7/8 speed systems as I'm already doing that and it's fine (as most manufacturers say anyway)

BUT will a modern 9 speed triple chainset work with older 7/8 speed gears and chain (ie. 3/32")? Or will the chain be too wide and creat noise and poor shifting? (not that I shift much between front chainrings anyway)

 

[bobones]

so, I know that a 9 speed rear mech can work perfectly well with 7/8 speed systems as I'm already doing that and it's fine (as most manufacturers say anyway)

BUT will a modern 9 speed triple chainset work with older 7/8 speed gears and chain (ie. 3/32")? Or will the chain be too wide and creat noise and poor shifting? (not that I shift much between front chainrings anyway)

I run a 9 speed compact double with an 8 speed cassette and chain and it's fine. There is some rubbing of chain against big ring in small-small combination, but that's one I don't use so it doesn't bother me. I imagaine a triple would be similar. I've read (but not tried it) that a 9 speed chain might solve this rubbing, need less trim, and still have good shifting at the rear on the 8 speed cassette. Don't know about 7 speed tbh.

 

[Smokin Joe]

It'll work.

Chains have only got narrower across the total width, the difference between the plates is still the same.

 

[e-rider]

It'll work.

Chains have only got narrower across the total width, the difference between the plates is still the same.

so would that mean I might be better off using a 9 speed chain as well?

 

[Smokin Joe]

A nine speed chain will cut down the chance of chain rub on the outer rings when running it at an angle.

*Edited in case you wondered how a narrower chain will stop your chin rubbing.

 

[e-rider]

are you sure that the inner width hasn't changed? and that a nine speed chain will sit on the teeth properly?

because what would be the point of a 10 or 11 speed chainwhip? If the inner width was the same then they would all fit.

 

[Mark_Robson]

I use a 9 speed chain on a 8 speed cassette and it's fine. And as an added benefit the narrower chain reduces rubbing and trimming.

 

[bobones]

are you sure that the inner width hasn't changed? and that a nine speed chain will sit on the teeth properly?

because what would be the point of a 10 or 11 speed chainwhip? If the inner width was the same then they would all fit.

Who said anything about 10 or 11 speed? The only assertion that matters in this case is that 8 and 9 speed chains have the same inner width. 10/11 is a different matter.

 

[e-rider]

Who said anything about 10 or 11 speed? The only assertion that matters in this case is that 8 and 9 speed chains have the same inner width. 10/11 is a different matter.

yes indeed.......

I'm actually using 7 speed and mixing the components with 9 speed items as decent 7 speed stuff is no longer available and I'd like the option of one day moving to 9 speed anyway. Unfortunately my wheel has a freewheel and not cassette so it's not so simple - shifters are expensive too. So far I've just put on a 9 speed rear mech and that works fine. Chainset was next up as the HTII system has many advantages and would save plenty of weight and avoid hassle of BB lengths

 

[andy_wrx]

are you sure that the inner width hasn't changed? and that a nine speed chain will sit on the teeth properly?

The internal width is the same, the external width is what differs.

Remember that the chain got narrower in order to get more cogs onto the cassette, not because of any chainring issue.

A 9sp cassette is (essentially) the same width as a 8sp cassette
But the thickness of the metal sprocket is nearasdammit the same - 1.80mm for 8sp and 1.78mm for 9sp
What allows a 9sp cassette to be the same width as 8sp is the fact that there are 7 x 3mm spacers in an 8sp cassette and 8 x 2.56mm in a 9sp .
http://www.sheldonbrown.com/cribsheet-spacing.html

Chainrings are the same - the thickness of the chainring is essentially the same 8sp vs. 9sp

because what would be the point of a 10 or 11 speed chainwhip? If the inner width was the same then they would all fit.

If the external width of a 7/8sp chainwhip is too great, then you won't get in on the cassette - particularly 10sp or 11sp, where the inter-cog spacers are thinner still.

 

[e-rider]

so the teeth are thinner but only by 0.02mm

good info - cheers