Rene Herse Umtanum Ridge, 650B x 55 - EnduranceRen Herse's largest 650b tire, the Umtanum Ridge is ready for a challenge. Rolling over boulders and climbing up roots is a cinch thanks to its massive traction patch. And with its heavy duty casing, the Umtanum allows you to hit the trail at speed with little fear of cuts or punctures. A perfect choice for bikes like the Open WI. DE or Mosaic GT X.