You might want to check out Peterwhitecycles.com. He has an interesting article about chainrings. Click on Chainrings once at his site. I ordered new chainrings for my bike from him. I'm going with 48-38-28 on my Ultegra cranks because I have bad knees and lots of hills around here. I changed out my 30 to the 28 and might even go to a 26.