Outdoor testing http://www.wheelenergy.com/apps/photos/ Outdoor testing Wheel energy yard http://www.wheelenergy.com/apps/photos/photo?photoID=200176619 200176619 MTB traction testing on gravel http://www.wheelenergy.com/apps/photos/photo?photoID=200176620 200176620 MTB comfort testing on gravel http://www.wheelenergy.com/apps/photos/photo?photoID=200176621 200176621