What percentage of you use something other than 53/39? Compact or giant? Does a 55 or 54 really make a lot of difference over a 53?
-Colin
54-44 on the TT’s and a 53-39 on the road bike!
Try Sheldon Brown’s Gear Calculator.
Compact 50/34 with an 11-23.
53/39 12-23 700C road bike
55/44 12-23 650C tri bike
Use the front chainring that gets you in the right gear for the riding that you will be doing, preferably near the center of your cassette.
jaretj