Originally Posted by
cappuccino911
FYI, there is also an eBay seller wheelandsprocket with some low cost road triples, you could make that change because you might have problems with your front deraileur if you go smaller with only one chain ring. If you go down to 39 you prob also have to make the big ring go down to 50. I got a truvativ elita triple with bottom bracket for 40 bucks. If you can't do install yourself lbs can do it for 20 bucks. It's a 52/42/30 setup.
Hmmm - a triple is a whole 'nother layer of complexity, and will almost certainly involve a new brifter for the front, and probably a FD too. The Ultegra brifters are specific for double or triple, and although a triple brifter can be made to work with a double crankset it's unlikely that the OP has a triple brifter on a bike originally setup for a double.
I have no idea why the OP would have to change to a 50 chainring in the front - Shimano sells 53/39 cranksets already. A 14 tooth drop between chainrings is not unusual.
JB