here2day

I have a 2005 Specialized Allez that has around 20k miles on it. I'd like to start replacing parts. The bike has Shimano 105 STI Dual Control shifters, 105 FD, Ultegra 6500 RD and 105 9 speed cassette.

I recently got an Ultegra 6700 RD and 6700 10 speed cassette at a great price. Will the current shifters and FD work with the new 6700 10 speed components?

Thanks for any advice.

caloso

No. The shifters have to match the number of cogs in the cassette.

catonec 

I believe the front deraileur will work with different shifters but the rear shifter (9) will run out of "clicks" for the 10 speed cassette. A rear deraileur (8,9,or 10) will be fine once you adjust the limiting screws.

so to sum it up to change from 9 speed to 10 you only need a right (rear) shifter and cassette to match. Assuming your not changing from a 2 ring to a 3 ring crank or vice versa.

here2day

Thanks - don't plan to replace the shifters yet so will use a 9 speed cassette until I do.
Ialso have a new 10 speed chain. Can I use it with a 9 speed cassette or should I use a 9 speed chain?

catonec 

Match the chain to which ever speed your crank rings are

IthaDan 

Shifers, chain and cassette are the minimum system requirements for a change of 'speeds'.

HillRider

The 10-speed chain should work with a 9-speed drivetrain. The opposite isn't true, a 9-speed chain won't work with a 10-speed drivetrain. However, since you have the 10-speed cassette and RD, why not save the 10-speed chain until you buy the needed 10-speed brifter?

Bill Kapaun

+1
Considering the price of 10 vs 9 speed chain, it'd be a waste of money to use a 10 speed chain on a 9 speed cassette.

here2day

Plan to put the 10sp components in the parts bin until I upgrade my shifters.

Thanks for all of the advice!!