The guy on the bicycles has the same animation every time, so it looks like it's the same speed, but it isn't :

--------------------------------------------------------------------------------------------------------------------I

The slow guy moves the slowest and moves in the same speed as if you (he was) were just holding W.

The normal guy is moving as if you (he) would combine pressing W and holding it.

And the fast guy is moving as if you (he was) were pressing W.

--------------------------------------------------------------------------------------------------------------------I

DYOM isn't programed to give the guys on the bicycles different animations, and that's why every bicycle guy has the same animation regardless of the speed he is moving in.

So you make the slow guy and he pedals as if he was faster but he isn't and it's just an animation.