Bicycle Mechanics - Chain Rub

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brooklyn
06-25-07, 02:35 PM
I notice on my road bike that when i am in the small chainring(double) and maybe the first and second cog the chain seems to rub on inner part of the larger chainring? I was thinking that is is a result of trying to use a 8 speed crank on a 10 speed drivetrain?
Normal behavior, particularly if your rings are 53/39 or more teeth apart. Just a part of crosschaining and you don't need to use those combos anyway.
Sheldon Brown
06-25-07, 02:51 PM
I notice on my road bike that when i am in the small chainring(double) and maybe the first and second cog the chain seems to rub on inner part of the larger chainring? I was thinking that is is a result of trying to use a 8 speed crank on a 10 speed drivetrain?
I think you must have it backwards...it is common for it to rub when you are "cross chaining" with the small front and the SMALL rear. Those are the high gears in back, not "first and second."
If anything, using "8-speed" chainrings should REDUCE this because they're sliiiiighlty farther apart, and you're running a narrower chain than they were designed for.
However, the current fad for frames with stupidly short chainstays makes this sort of thing very common.
Best advice is to avoid those gear combinations. You should never, ever ride in the small/small combo, and the small/second-smallest is generally also a poor gear to be using for anything but a temporary transition.
Sheldon "http://sheldonbrown.com/gears.html" Brown
brooklyn
06-25-07, 08:52 PM
thanks for the response. I did have it backwards. for some reason i always get confused with high and low gears.
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