Felt Ar2 Ult Di2 2013 Road Bike. A culmination of years of design, wind tunnel analysis, and pro testing, the AR2 gives you every aerodynamic advantage possible. The UHC-Advanced material that’s used to craft the AR2’s frame is more than just a high-grade carbon fibre. It’s a custom blend that is engineered to give Felt’s pro riders-and you-the incredible ride quality that makes this bike so unique. Combining supreme aerodynamics and superb ride quality, the AR2 is ready to race.