Bicycle Mechanics - difference b/w double chainring crankset ?

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farrenator
05-27-03, 09:28 AM
Is there a difference between double chainrings for different cog casettes, eg. a 7 speed casette or a 9 speed casette? Shouldn't the same double chainring crankset work for both casettes? I understand the need for different BB for double or triple chainrings, and the need for different deraileurs, but shouldn't the same chainring crankset work?

Thanks,

Victor

RegularGuy
05-27-03, 10:23 AM
The differences are chain width and spacing.
dexmax
05-27-03, 11:20 PM
i didn't know there are compatability problems?

I sure have not encountered such.

I have used my crankset(used w/ 7spd cogs) with new 8 spd cogs w/ hg5x chains.

RainmanP
05-28-03, 06:37 AM
I upgraded a mid-'80s Bianchi from 6sp rear to 9sp, and the crank works fine with both the new STI shifters and front der. Cranks seem to be more forgiving in terms of compatibility.
farrenator
05-28-03, 07:25 AM
I didn't know there were any problems either. The only reason I brough this up was I saw in a few classified ads that the cranks were advertised to work with 9 speed casette, or a 7 speed freewheel etc. I got to thinking about it and I couldn't see how it wouldn't work with any combo. But, I am new to bike mechanics so I figured I would ask.

I used to just ride and not think about how it all works together, and now I am trying to figure out that aspect.

Victor


Originally posted by dexmax
i didn't know there are compatability problems?

I sure have not encountered such.

I have used my crankset(used w/ 7spd cogs) with new 8 spd cogs w/ hg5x chains.