 In general there are no push-rims and propulsion/braking is by pushing directly on the tyres.A more common variant is the beach wheelchair (Beach-Going Wheelchair) which can allow better mobility on beach sand, including in the water, on uneven terrain, and even on snow.The common adaptation among the different designs is that they have extra-wide balloon wheels or tires, to increase stability and decrease ground pressure on uneven or unsteady terrain.