Crank Brothers Iodine 2 27.5 Mountain Wheelset. Ready for some serious 27.5650b all mountain wheels The Crank Brothers Iodine 2 27.5 mountain wheelset are as striking in their appearance as their performance out on the trails. Crank Brothers, in a fashion, have re invented the mountain bike wheel. Their Twinpair spoke design forms triangulated load bearing structures, providing superior strength and lateral stiffness, with just 24 spokes per wheel. Serviceability is incredibly simple as there's only one spoke length throughout the front and rear wheels and spokes can be replaced without removal of the cassette, rotors, or tires. Ride wise, the unique wheel design equates to reduced rotational inertia for improved performance and faster acceleration. The 23mm wide aluminum rim is stout and tubeless ready while aluminum hubs with sealed cartridge bearings roll super smooth.