At 48 mm wide, the Switchback Hill is our largest 650B (27.5?) tire yet. Switchback Hill is the first and only named climb on the 360 mile Oregon Outback gravel ride/race. The gravel is quite loose in places, and the extra floatation of the Switchback Hill tires gives you more speed and security when the going gets really rough. 30% of the Oregon Outback is on pavement, so we designed this tire to roll as fast and grip as well as a good racing tire. With this tire, you truly have the best of both worlds. The Switchback Hill also can transform the performance of your 27.5? mountain bike on gravel or paved roads. The Switchback Hill is tubeless-compatible in both standard and extralight casings. When used with tubes, we recommend the Schwalbe SV13. Made in Japan.