Originally Posted by
rpenmanparker
Why does a tubular road rim need to be wider than the historical standard? Wider glued-on tires don't require wider rims. The base tape generally matches even narrower rims. And no matter what rim width, the tire shape stays the same. You don't get the same aero improvement with tubulars on wider rims that you get with clinchers. A 20 or 21 mm wide tubular rim would have been considerably lighter than even these very light rims.
Wider tires on wide tubular rims will provide some miniscule aero benefits relative to wider tires on conventional (20mm) tubular rims. But 22mm tires on conventional tubular rims would have less frontal profile, they would be even more aero. And a lot lighter.
The reason for the recent fat tire thing is to provide the extra air volume so that riders on clinchers don't get as many pinch flats. But since tubulars are basically immune to pinch flats (the smooth rim profile), this trend does not translate over to them. So you can run 22mm tubulars at lower pressures over bumpy terrain, and not have to worry. I do this almost daily.
So once again, the benefits of tubulars are manifested: lower weight, less fragile rims, immune from pinch flats, and much safer after a blowout. And you don't have to run fat (heavy) rims and tires to benefit from lower inflation pressures.