Originally Posted by
msu2001la
FWIW, Zipp's latest wheel (353NSW) is a 25mm internal rim that they say is aero optimized for 28mm tires.
Very interesting, thanks. I read another source that say their similarly wide rims are optimized for >2". And the charts I've found lately are all over the place. I'm going to fit a 35 on a 25 iw rim but can't find a definitive guide. Based on what you wrote and another source I quoted above, I'm going to give it a shot. But many of the charts I've looked at say the rim should be several mm narrower than that, some day it's ok.