For 2006, KTM comes with the dirtybike 560 SMR. It is lightweight at 241 pounds and is a four-stroke liquid cooled, 566cc machine that won’t let you down. The 560 SMR has a higher compression ratio and larger engine displacement. Interestingly, it has the same bore as the 450 SMR, but has a longer stroke. Both models are equipped with 17-inch diameter, 3.5-inch wide front wheels and larger 17-inch diameter, 5- to 5.5-inch wide rear wheels. The larger rear wheel accommodates the bigger, more rugged race compound tires available today.