My Cervelo P2 has Dura Ace front/rear derailleurs, the ear wheel has Shimano 6600 10 speed cassette, it runs well.
Now I want to use a pair of old Corima carbon wheels. The rear wheel, a 4-spoke, has Shimano CS-HG70-9 9 speed cassette.
I did two experiments:
I put on the 9 speed carbon wheel directly, it seems to run well, chain can be shifted from smallest ring to largest without skipping a ring. 10 speed shifter misses 1 gear of course: shifting from the smallest ring to the largest, the first shift has no effect.
I replaced the cassette of 9 speed carbon wheel with Shimano 6600 10 speed cassette. I did some search, all say it's fine to put 10 speed cassette onto 9 speed hub. Put the wheel back on bike, the chain can only go from the smallest ring to second largest ring. 10 speed shifter misses 1 gear still: shifting from the smallest ring to the largest, the first shift has no effect.
Q1: can I just use the 9 speed carbon wheel on my 10 speed bike? will it cause damage to the chain set? I think the 10 speed chain is thinner, no?
Q2: how come I'm missing 1 speed after replacing the 9 speed carbon wheel with a 10 speed cassette? do i need to adjust the rear derailleur?
update: I figured out the cause: when I moved the 10 speed cassette I left a 1mm spacer on the hub, as described here: http://www.bikeforums.net/bicycle-mechanics/781234-shimano-10-speed-cassette-washer-shim.html because of missing this 1mm spacer, the whole cassette is 1mm closer to the spokes, 1mm further from derailleur. as advised, I adjusted the rear derailleur and managed to get shifting back, but by putting that 1mm spacer back on, the derailleur is off again... though I wasted some time due to this rookie mistake, I actually learned a lot. thanks for all who helped