Originally Posted by
HillRider
The "floating" (aka skating) problems you were told about came during the transition from 8 to 9-speed. The narrower 9-speed chain would sometimes skate on the teeth of the smaller ring if the shift was made under high chain tension. Even then it was a minor issue.
This floating came about when 9 went to 10 speed as well. Mostly when FSA for example tried to market their 9 speed cranks/chainrings as 10 speed compatible.
They were not.
The chain would skate in between the rings, notably on campy 10 speed compacts and FSA compacts. This is VERY dangerous if someone shifted coming off a stop light to lose the entire drivetrain mid intersection.
FSA responded by redesigning their chainrings to bring them closer together. It is this *exact* problem which leads the chain to rub/hit the large ring in the smaller rear cogs on most 10 speed setups. It doesn't matter anyways, those gears are redundant.
Shimano 9 and 10 speed rings are speed specific. If you try and mount a 10 speed ring on a 9 speed crank shifting WILL suck. As an experiment, mount the inner ring on a double backwards. The chain will skate like a mother****er.
Originally Posted by
well biked
It happens, I've seen it. I didn't think this would be a problem until I saw it happen in person, but it does happen, occasionally. I've seen it on two bikes in three years in our shop. It certainly isn't a problem on all of these "mismatched" situations, but if it does happen you CANNOT get the front shifting to be reliable, the "floating" will occur intermittently no matter what you do, no matter what you adjust. In the two cases in our shop, switching to cranks designated as "ten speed" solved the problem immediately. It can actually be dangerous if it does happen, because when you shift to the smaller ring and the chain doesn't engage the chainring......it can hurt.
Spoken like someone who actually works on bikes for a living. Bravo.