Originally Posted by
fuzz2050
It's only going backwards that it can become an issue. A 6/7/8 speed chain on a 9/10/11 speed derailer isn't the best idea.
I'm not the kind of guy who measures stuff like this unless I encounter a problem. I seem to remember reading somewhere, however, that the inside chain dimension is the same. All the narrowerness is made up in the outer plate design.