ISR & ROLLING RESISTANCE: The rolling resistance of tires is dependent on the amount of energy absorption. A fast tire absorbs very little energy while a slow tire absorbs a lot of energy. Slow tires can become extremely hot, so hot that they rupture. Instead of using high energy absorbing rubber, V2 uses a patented kinematic damping system to increase rolling resistance. But, with a split rim V2 could not employ their standard kinematic system. In order to increase rolling resistance we added a 22 mm pocket on the inside of the split rim. In this pocket V2 press fit the ISR ( Internal Speed Reducer). The ISR has two elastic sealing lips that rotate around a very precise hardened steel spindle. Between the two sealing wipers is a high viscosity lubricating fluid. This system increases the rolling resistance by about 15 to 20%. The heat generated is dissipated via the aluminum bearing tube and aluminum bolt fastened to the wheel forks. So, with just one tire you can have a ski with three different speeds. Put an ISR into one wheel of the ski and you have a slower ski. Place the ISR into both wheels and you have the slowest combination.