Originally Posted by
Triguy
Shimano's aluminum clinchers don't look that great initially on paper but have a few things about them I really like...
1. Great rim shape, it is 21mm wide, which counter intuitively is more aerodynamic, it creates a smoothe bridge between the tire and the rim(a bullet instead of a lightbulb like most rims), and allows the system to outperform most 27-30mm deep rims.
Do you have any numbers to support this claim? Everything I've seen show that you don't see noticeable aero benefits until you get at least 30 mm deep.
I do agree with the bulging statement. You do want to get tires that once inflated are the same width as the rims. Assuming that is true of your 30 mm rim tire combo, I don't believe these would be more aero.