I have a bike with a standard 6600 triple group and 12-27 cassette. The cassette and chain are shot and I wondered if I could get away with putting the new 6700 11-28 cassette on.

Shimano specifies for the 6600-GS rear der a 27t max cog and total capacity of 37 that would be exceeded by 2 with 30-52 rings and 11-28 cassette. So it's not a supported config.

But 11-28 would be handy also for use on my other bike with 53/39 (e.g. at Battenkill next week) and Nashbar has it for a good price.

Does anyone have experience with this arrangement or can make a good guess?