Bicycle Mechanics - changing from an Ultegra 12/27 to an Ultegra 11/28
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02-13-10, 07:33 PM
Hello, I'd like to change from an Ultegra 12/27 to an Ultegra 11/28. My current Ultegra 6600 RD and 12/27 shifts extremely well and hope to have the same smooth shifting with the 11/28.
The Shimano website says that I need to upgrade to a 6700 RD to accommodate the 11/28 but I've heard that the 6600 RDs work. If I upgrade to the 6700 RD will that substantially improve shifting?
Will I my 6600 brifters work with a 6700 RD?
02-13-10, 07:36 PM
Shimano don't recommend it on their site, 27T supposedly the max for the RD6600 but plenty of people running 28t without issue. The shift up to the 28 won't be very crisp but it gets there fine. You will have to adjust the B-screw on the RD to it's max more then likely.
02-14-10, 09:52 PM
I just made the same change, 12-27 to 11-28. Put the wheel on both my bikes, Ultegra 6600 RD long cage, and DuraAce 7800 RD short cage with NO changes. I did carefully test shifting on my stand before riding to make sure the chain length was still OK.
I made the same change on a friend's bike with Shimano 6600 because he could not find a 12-27. The new 11-28 worked perfectly with no adjustments needed. We also replaced the chain with a 7800.
You will need the special lockring to go with the 11t cog.
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