I keep seeing model numbers like 6600, R770 pop up. Is it necessary to choose the same model numbers to get everything lined up? I see many people mixing and matching components, are there any issues I should watch out for if I do this?
6600 series is the Ultegra 10 speed series. SL signifies a later release version that is mechanically the same as the standard version but some of the components are a bit lighter and it is grey in color instead of raw aluminum. R770 is a compact crank version of the Ultegra 6600 crank.
As far as mixing different groups go. All 10 speeds stuff are compatable with each other EXCEPT the new 7900 group. You can mix Shimano 105, 6600 Ultegra and 7800 D/A with no issues.
Thanks for the response, a little unrelated but can anyone confirm that the Ultegra 10spd triple front derailleurs are compatible with double? I am seeing advertisements for a few different models that claim to be. I'm sifting through some forum posts and it isn't too clear whether this is the case or not.
Shimano make different double and triple dérailleurs for a reason. However, saying that mixing and matching is possible, but likely the shifting won't be as smooth as it could be. A triple dérailleur should work with a double crankset but probably not the other way around. The triple derailleur is designed with a wider cage to allow for a wider chain angle and the inside plate comes down alot lower to allowing shifting up from the smallest chain ring. Though the front derailleur is the cheapest part of the groupset, I'd just pick one up second hand or get one from a cheap online store. I have one spare if you're interested, though postage probably make it not worth it.