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Discussion Starter · #1 ·
I finally finished (in my spare time) my wife's bike. Well, it has one last issue. It's an old school/ no suspension Cannondale. I picked up some newer shifters, derailures, wheels, cassette, brakes so the bike would be a bit more modern. Well, that and the suntour shifters and deraileurs were worn. I probably could have overhauled the deraileurs, but I was able to get some newer stuff pretty cheap.

The question is: Am I asking for trouble trying to using the original 7 speed triple chainrings with a new 9 speed cassette and derailur system?

I have newer shimano front and rear mega 9 compatible deraileurs and shifters, a new sram 9speed narrow chain. The original drivetrain was Suntour XC with 7 speed xpress shifters. I was hoping to keep the original chainrings and cranks

Thanks
DH1
 
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don't you need a narrow chain for the 9spd cassette that may not work on the thicker 7spd rings? if you need to swap chain rings anyways get 9spd rings for the 5arm 110mm cranks. i know that shimano makes them for the XTR M952 cranks (expensive i guess) but would not wonder if they are available from cheaper aftermarket brands as well.

Carsten
 

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Mantis, Paramount, Campy
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Not Really Necessary

If the 'rings are in good shape there's no need to change them. A 9spd chain will work fine on 6/7 spd rings. The difference in thickness is minimal.
 

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Discussion Starter · #6 ·
Carsten said:
don't you need a narrow chain for the 9spd cassette that may not work on the thicker 7spd rings? if you need to swap chain rings anyways get 9spd rings for the 5arm 110mm cranks. i know that shimano makes them for the XTR M952 cranks (expensive i guess) but would not wonder if they are available from cheaper aftermarket brands as well.

Carsten
The chain seems to fit on the chainrings fine, but doesn't shift up to larger chainrings as easily as I expected. The chainrings aren't worn out, and the chain doesn't skip....it just seems to me that the deraileur doesn't want to throw the chain to the next larger ring reliably. The original chainrings don't have steps on the sides to aid in shifting, and perhaps that is part of the problem with the narrower chain and deraileur.

Since I posted this yesterday I went home and unhooked the front deraileur cable and re-calibrated it from the beginning again, per Shimano instructions. It seems much better now. I posted the original message because the same shimano instructions said that you could not use a 9speed chain on chainwheels designed for a 7 speed setup. It said that it could break the chain...I read that to mean that they were just trying to sell more chainrings....like when your Chrysler says only to use a MOPAR OEM battery in the owners manual. Shimano wants you to buy Shimano everything as often as possible.

DH1
 
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