I rode one for 400 miles last winter. 80mph tops on the trail, 85 on a plowed road. Gets up to 60 pretty quickly, but then creeps from 70 to 80. In loose, fresh snow on the trail I could only manage 72-75. They are geared pretty low. SnowTech mentioned that they could be geared up for better top end. For a fan, hey are a hoot from 0-60 on a twisty trail.