spocket wrote:
I wish I knew this was coming before getting new race wheels from HED over the winter for my new disc-brake bike.
I would have liked the wider internal rim width and slightly deeper profiles.
oh well.
I first heard rumblings about people riding the new rim profiles last fall. If you have the new graphics I wouldn't be surprised to find out that they are the new rim profile. I also don't think internal width has changed. At least for now, it seems that most of the top brands have settled on 20-21 mm for hooked rims that are "optimized for 28mm" tires/tyres. The hooks reduce the internal width by probably about 1mm each, so I think your 21mm internal width is sort of equivalent to about a 23-4mm hookless rim.
The one thing I that I think has been neglected in the discussion of rims and tire widths is their effect on corning speed. The Tri/TT crowd tends to focus on straightline aerodynamics. If you have been watching the pro road racing TTs these days, you probably realize that cornering speeds are becoming way more important. Increased cornering speed would be a much bigger deal than any small gain in Crr from using a wider tire or aero savings from using a narrower tire.