KTM ATVs include 450SX, 525XC, and the championship winning 505SX. KTM ATVs and Quads are becomming a common site at many off-road races. The Austrian brand, while reletively new to ATV market, has made a big impact with its 450SX and 505SX ATVs. With KTM’s recent ATV racing success you can bet the KTM ATV line will continue to grow. History of KTM Motorcycles.