On U shaped rim (widest near the middle of the rim) it was tested that rim must be at least 105% as wide as the tire to get best aerodynamic.
How about V shape rim that is widest at the brake track (like your rim)? Does this rule still apply? If not, what is the recommended ratio between rim width and actual tire width?
Did you read the previous reply from Victor? See below.
In ideal world, you'd want the rim marginally wider than the tire (e.g. 105%). If you tire is wider than a rim, the penalty is ~1 watt. Rim and tire ratio, should be the least of your worries.
Rev 35 (27mm outer, 19mm inner)
Rev 507 (28mm outer, 21mm inner)
I could not make the U shape work with a 50.7mm profile and 25mm wide tires without going crazy wide - over 32mm or so. Extreme width adds weight and can present compatibility problems. So what I did was still use an extended laminar flow airfoil, but sacrificed some performance at the leading edge at tangent, but gained some of it back at the higher and lower portions of the 507 rim, and at the trailing edge. At the trailing side of the 507 rim the airfoil shape is excellent and in simulation at least (good simulation) it generated a very stable wake.
I will have some wind tunnel data later this year, but we already have handling feedback from test riders and normal riders and it is excellent.[/quote]
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