What has four mountain bike tires, disc brakes, no gears, and no pedals? Nope, it’s not the pile of cannibalized bikes in your tool shed, it’s the R-one 4×4 – the raddest way to ride downhill on four wheels. The Rough Riderz club in the UK is working hard to increase awareness of this (new?) form of mountain biking for both wheelchair and able-body riders alike. The bikes are a bit pricey (more than $6000 for some of the rigs) but judging by the photos on the Rough Riderz website there really isn’t much you can’t do with one of these things.