Suppose you're hesitant to try Rotor's ovalized Q-Rings. It could be that you don't have any knee problems, have been riding standard round rings for years, and if it ain't broke, of course you shouldn't be messing with it. We understand, and so does Rotor. That's why they also make round chainrings. Rotor's Round Road Aero Chainring is just the thing for your time trial bike in order to make it as fast as possible. Like other their Q-Rings and other high-quality chainrings on the market, they have stainless steel pins and machined ramps for superb shifting from the small ring and back. The big difference is that the Aero Chainring is a solid plate of hard anodized CNC machined aluminum and lacks the complete cutouts of the standard road outer ring. The inner surface is heavily machined to rid any extra grams. Ultimately, it's a few grams heavier, but it's certainly more aerodynamic and is stiffer to boot. In fact, more powerful riders often prefer the aero because of its stiffness during all out efforts.Rotor Round Road Outer Chainrings are CNC machined from 7075-T6 aluminum, and they have a hard anodized black finish with laser etched silver graphics on the outboard side. They fit Rotor Agilis and 3D Cranksets and are also compatible with any crankset using 130mm BCD (bolt circle diameter). They're available in two sizes -- 53t and 54t.