This is the second version of a 650b mountain bike from Ritchey -- Tom started to design his first in 1977. Even back then, Tom had a feeling that there was an advantage to the "middle" wheel size, but it took the rest of the cycling world three decades to figure it out: a 650b (or 27.5") wheel provides the bump-eating smoothness of a 29er, with the light, responsive feel of 26" wheels. Finally, the era of the 650b wheel is here. The P-650b is a close relative to the P-29er. Up front there's the proprietary forged-and-machined, gram-shaving integrated head tube featured on all new Ritchey frames. Forged socket dropouts nd new chainstay-mounted rear disc brake mount save a few more grams. And like every frame we make, geometry and tubing is carefully fine-tuned by Tom, to bring the legendary balanced, nimble Ritchey feel to 27.5" wheels.