Zipp 1Zero HiTop S Rear Wheel - 29, 12 x 148mm, 6-Bolt, Micro Spline, Tubeless, Carbon, A1The 1Zero HiTop S wheelset melds high value with high performance for a better and faster ride. Trail compliance is vital, with modern cross country courses becoming rougher and more challenging. No longer is it good enough for an XC wheelset to be stiff above all else. Instead, a wheelset should feel alive. The 1Zero HiTop S carbon rim complies with the terrain thanks to Zipp's proprietary HITOP Technology for carbon layup. The result is a light XC