# Ultegra 6603/6503 Compatibility



## aggieman (Feb 25, 2002)

I am interested in upgrading a bike to a TRIPLE Shimano Drivetrain from double.

Want to know if the following 9/10s combination will work ok? Particularly will the Front chainrings shift ok with the 6603 Crankset and 9s chain?

Mix of components would like to use:

RD-6600 GS Long cage Rear derailleur
FD-6603 Front derailleur
FC-6603 Triple crankset & bb
CS-6500 9 speed cassette
Shimano 9s hg93 chain
Shimano 9s 105 STI levers.

Thanks very much for any help/comments.


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## rriddle3 (Aug 5, 2004)

They should work together, but you need to change the bottom bracket to the one designed for a triple crankset to get the chainline correct. Are you planning to eventually go all 10 speed? If not, why not get 6500 parts instead of 6600?


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## BarryG (Jul 5, 2004)

rriddle3 said:


> you need to change the bottom bracket to the one designed for a triple crankset to get the chainline correct


Huh? The 6603 crank includes the axle. Just need the SMFC6600 bearing set, which is double/triple compatible.


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## rriddle3 (Aug 5, 2004)

Absolutely right! Just a momentary brain fart.


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