Because metal is durable and leightweight
To do bicycling you need a bicycle. And the bicycle is a man-made item relying heavily on techology to provide all the bits and pieces.
Cheap bikes are made with cheap parts. Plastic pedals are cheap to make. Better pedals are made out of metal. (Worth noting: better bicycles don't come with pedals at all. This way the rider can get the pedal system that works for the rider.)
The threads on bicycle pedals are American Standard.
Motor cars and Bicycle's both have pedals.
bicycle
How fancy do you want them to be? Cheap pedals are die-cast. Expensive pedals are machined.
what metal is it answer a.s.a.p
Velocipede
That'd be the crank arm.
Two
A motorcycle has a motor and no pedals
Bike pedals can be made up of a lot of different kinds of materials. Pedals can be made up of metal or plastic for example.While it's more than 100 years old, the bicycle has undergone a lot of changes since its inception. The sizes of the tires have changed, the material it's made from has altered, and the pedals have changed their design and materials over the years.