BRAKE LEVERS:
Bicycle brakes decreased speed.

A HAND CRANK:
A clank is a class2 lever,so it obeys the law of the lever
F-is the force that we apply
D-distance from the axis of rotation
R-in the shaft.

BICYCLE HANDLEBARS: 
If we put our hands near the middle,it´s more difficult to turn the handlebars.It is easier to turn a larger steering wheel becouse there is a larger distance between the outside of the wheel and this axis of rotation in the centre.