Originally Posted by Farleybob
Where do I find the model of 105 or Ultegra deraileurs and shifters? I have 105 shifters and a 105 front deraileur and Ultegra rear. I am currently 9 speed on a 2006 CAAD8 R700. How do I know if I am ten speed compatible or not?
Unhook shifter cable, while pulling lightly at the cable shift all the way out to the end position. While maintaining tension on the cable, shift all the way in while counting the number of positions. There's your answer.
If your bike came stock with a 9-spd cassette, then the odds are overwhelmingly good that your shifters will also be 9-spd, there's no way a shop is gonna sell a mismatched set.
Different numbers of speeds requires different actuation ratios in the shifters and different spacing in the cassette, so it's quite rare to have a (rear) shifter that is compatible with more than one number of speeds (although I believe some bar-end shifters are labeled as such).
There are ways to make mismatched combos work, but I doubt that any shop would sell such a setup w/o making it excessively clear to the customer what he was buying.
Derailers are considerably more lenient and are usually quite unconcerned with what numbers of speeds they're used with.