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9/10 speed cranks(5 posts)

9/10 speed cranksnat_ct1
May 15, 2002 8:10 PM
is there such a thing as a difference between a 9 speed crank and a 10 speed crank?? the guys here were told that last night at the bike store.
re: 9/10 speed cranks mtb insightjon_gl
May 16, 2002 1:18 AM
In the case of a mountain 8 and 9 speed, the chain width was slimmed down to make room for the extra gears and the chainrings were re-sized to the 9speed chain. In campy's case the chain width for 10 sp are 6.1mm and the 9 speed is 6.8. We can only assume that the chanrings on the crank accommodate the (.7) varying width of campy chains, although I cannot say for sure.
I assume so.Spoke Wrench
May 16, 2002 4:59 AM
The Quality Bike Parts catalogue has Campy cranks classified as "10-speed compatible" and "9/8-speed compatible." I assume there is a good reason why they do it that way. I can only guess at what the reason might be.
There is a slight difference, but...Cima Coppi
May 16, 2002 5:29 AM
It does not really affect the shifting performance of the front derailleur. Campy has designed the 10 speed outer chainring to be closer to the inner ring than on the 9-speed crankset. This is supposed to accomodate the narrower C10 chain.

From comments of others on the board, there is not really an issue if you use the 10 speed drivetrain with 9 speed spaced chainrings. I have not heard of anyone going the other way around, and use a 10 speed crankset with the 9 speed drivetrain.

the history...C-40
May 16, 2002 8:30 AM
When campy changed from 8 speed to 9 speed in '97, they made no changes to their crankarms or chainrings. When shimano made the change to 9 speed, they moved the little ring closer to the big ring and used a narrower chain than campy. When campy introduced 10 speed, they moved the big ring closer to the little ring and made the 10 speed chain a little narrower than shimano's 9 speed chain. I don't believe that any changes were ever made to the thickness of the rings, just the spacing between them.

Shimano 9 speed cranks reportedly work fine with campy 10, since both have rings that have been moved closer together and are intended to work with chains that are only slightly different in width.