Thumb Score: +12 Cervelo, the preferred bike of active dentists, everywhere -- this is an all carbon frame, with Shimano's new-er 12 speed 105 Di2 shifters. It is even equipped with Shimano 105 carbon wheels shod with very high end Corsa G2 tires in a 28mm width. Cervelo warrants their frame, like Trek and Specialized - for life.