There are quite a few types of helmets, including a rather surprising paper-made innovation that won a £30,000 sponsorship award in 2016. Below are broad categories of bicycle helmets
It is typical for road cycling helmets to lack a visor, a design that aids in improving visibility while riding. They are made to be extremely lightweight (enhanced by lack of a visor), compact, and streamlined. When compared to mountain bike headgear, they are better ventilated with many vents, and generally appear prettier.
The customary mountain bike helmet design has a visor to protect against the elements when cycling off-road and in forested areas. Usually, the frame extends at the rear to ensure enhanced protection to the back of the head while riding in challenging terrain. For these helmets, there is a greater variety of choices including full-faced options for downhill riding and for cross-country athletes. They are made to be light and strong with fewer larger vents.
They are simple helmets ideally used when commuting to work or for recreational town cycling. Though a cross between mountain bike and road cycling headgear and may have a small visor and some vents, they somewhat look like baseball helmets.