I just bought a Serrota Ti double crank Ultegra bike and am converting it to a triple crank Ultegra. It currently has 6600 series components. It seems the 6700 components are easier to find and cheaper in some cases. I've looked at the compatibly charts and read the forums and it seems that the following combination is valid. Please let me know if you see any problem in this setup or if you see where I am changing something that does not require changing:
Thanks for the quick responses!! Is replacing the cassette more of a good practice - or is it common to see a skipping problem? I've been riding for about 20 years - through 3 or 4 bicycles and I've replaced the just the chain a couple times here and there by itself. I've not seen this problem before - although I've heard this. My riding buddy had his chain skipping on climbs not too long ago. After some observation, we determined it was in his chain rings. We replaced his chain and all the chain rings (3) and he has been problem free since then. I have nothing against changing the cassette - I just want it to be worth the dollars.
I've been playing with this, using a PG1050 11-32 & Shimano 105 (5700) GS RD and did a very hilly ride yesterday, and it was nice to have the 30 / 32 rather than the 27 max I previously had with a 12-27t.
I thought that the GS rear derailleur will have the same spec. for cassette large sprocket capacity as the non-GS road derailleur. The longer cage is only intended to have greater take up capacity for the triple chain ring. I'm not saying it won't work with the 32t sprocket, but just that it is no more likely than a regular short cage rear derailleur.
Please correct me if I'm wrong.
I put a Deore XT RD on my wife's Tiagara 9 speed setup and it works great with a 34t cassette.