Motorcycle handlebar

A Motorcycle handlebar is a tubular component of a motorcycle's steering mechanism. Handlebars provide a mounting place for controls such as brake, throttle, clutch, horn, light switch and rear view mirrors; and they may support part of the rider's weight. Even when a handlebar is a single piece it is usually referred to in the plural as handlebars.

Handlebars come in a variety of types designed for particular types of riding:

Handlebars are made from round-section metal tubing, typically aluminium alloys or chrome plated steel but also of carbon fibre and titanium, shaped to the desired contour. Holes may be drilled for the internal routing of control cables such as brake, throttle, and clutch. Risers hold the handlebars above their mounting position on the upper triple tree or the top of the fork, and may be integrated into the bar itself or separate items. Each handlebar end may contain bar-end weights to damp vibration by isolating the bar's resonant frequency from that of the engine. Electrically heated grips may be fitted to provide warmth for the rider in cold weather.

There are several size parameters that describe most motorcycle handlebars.

...
Wikipedia