I have running shorts that have an extra inlay which functions as sort of underwear. So I dont feel as if Im going commando but I kind of am. In winter I go commando in leggings and wear the shorts on top to cover up a bit. If youre not going commando you should put thought into what material youre going to wear as underpants because not being breathable in your crotch area, especially on a bike is going to be extremely uncomfortable.