Here Klos I'll explain, since you don't know how bikes work:
You have 2 pedals, opposite eachother on a gear called a sproket. This is mounted on a ball bearing at a connection point on the bike frame below the seat. You have a front tire and a back tire. The back tire is the drive tire. It has it's own set of sprokets to drive the back tire. There is a chain that transferes power from the front sproket to the rear sproket, that's how you move the bike...Your feet turn the front sproket by going up and down, pushing down on the pedal while you lift your other foot up. The chain turns around the sproket, and goes on the teeth of the sproket. If you wear baggy pants, the lower part near your feet has a good chance of getting caught between the chain and sproket, and as you pedal it pulls your pants, and you, down. If your pants are baggy there's a good chance that they will be pulled down off of you, and if your pants are tight, you will be flung off the bike.
There, I hope I didn't confuse you too much Klos, we wouldn't want that...
