To me, mountain biking is mountain biking. Your on a trail riding over all different terrain, grass, sand, rock gardens, big rocks, drop offs everything on that trail your riding, whether its considered XC or single track..Maybe there is a real difference and I just dont know about it but when I go out to ride I am going mountain biking..eah some bikes are more considered XC bikes or singletrack bikes but to me they can and should be able to handle both because no matter what there most likely going to run into the some of the same terrain. Guess I just never really understood the difference or thought about it like this. 06-26-2011 #2.