Filament wound 50.7mm profile rims for rim brake bicycles. Designed specifically for enhanced aerodynamic performance with wide tires. The 507 rims are a result of our extensive experience with aerodynamics. The goal was to deliver a rim shape that is not only aerodynamic, but exceptionally stable in crosswinds. What is the point of a wheel being aerodynamic if it is too scary to use as soon as there is a little bit of cross wind, or even in city traffic? The Venn 507 handles exceptionally well and achieves optimal aerodynamic performance with tires that inflate to 25mm width.