A note on scope
This article is about how helmets were designed and who wore them, in the period before lightweight foam helmets became common. It is a history of design and not safety advice, and it makes no claims about how much protection any helmet gives.
Caps and pith helmets
For the first decades of cycling, riders wore ordinary hats. Racing cyclists in the late nineteenth and early twentieth centuries often wore cloth caps, partly to keep sun and sweat out of the eyes. Cycling in this period was mostly done at modest speeds, and the idea of a special protective helmet was not widespread. Motorcyclists, aviators and military personnel were more likely to wear protective headgear, and some of their designs later influenced cycling.
The racing hairnet
The first widely used protective item in road racing was the “hairnet,” which is also called a leather helmet or “leather strips.” It consisted of several padded leather straps, joined together, that formed a loose cage over the head. It was not designed to withstand a high-speed impact, but it was intended to offer some padding and to protect against scrapes.
Hairnets were worn by professional racers for several decades, mainly in the middle and later twentieth century. They were light, ventilated and allowed the rider to feel cool in the heat. They were also easy to wear under or without a cap. In many professional races of the time, riders could choose whether to wear one, and many chose not to. Precise dates are hard to give, since the style developed gradually and varied from country to country.
From racing aid to protective equipment
The 1970s saw growing interest in head protection from several sources. Cycling was increasing in popularity in the United States and elsewhere, and interest in testing and standards was growing in other sports and in motoring. Companies that made helmets for motorcycling and auto racing began to consider cycling models.
In this period, some manufacturers developed rigid helmets with a hard plastic or fiberglass shell and an inner lining. These were generally heavier and hotter than the hairnet, but they were designed to spread an impact over a larger area. The materials they used reflected progress in industrial chemistry and in plastics that built on earlier inventions such as bakelite plastic, which had made molded shells possible decades earlier. The straps that held them in place were often made from woven synthetic fibers such as nylon.
Why the hard shell was controversial
Hard shell helmets were met with mixed reactions. Racers complained of weight and heat, and ordinary riders often felt that the helmets looked awkward. The shells were designed for sports in which crashes could be high speed, and cyclists were unsure that they were necessary. Many people also wanted to avoid the expense. As a result, uptake was low, and for years most cyclists continued to ride without any head protection.
Another challenge was a lack of standards. Different makers used different materials and tested in different ways, so it was hard to compare their products. The Snell Memorial Foundation, which began as a response to the death of a racing driver in 1956, started to publish helmet standards in the following decades, and bicycle helmet standards eventually followed. For the purposes of this history, the key point is that testing was becoming a regular part of helmet design.
What the hard shell contributed
Even though the hard shell design was eventually overtaken, it left a mark. It introduced the idea that cyclists could wear a purpose-built helmet instead of a cap, and it showed that bicycle helmets could be produced in volume. It also set up questions that later designs tried to answer, including how to reduce weight, keep the rider cool and allow adjustment for different head sizes. The next step, the move to lightweight foam liners, is a separate chapter of the story.
Roads, speed and culture
It is worth remembering that attitudes toward helmets changed along with the conditions of riding. On the roads and highways of the early twentieth century, traffic was lighter and slower, and many cyclists rode short distances. By the 1970s and 1980s, cycling was changing, with faster road bicycles, off-road riding and more cars on the road. Interest in headgear reflected those changes.
Summary
The hairnet and the hard shell are two early chapters in bicycle head protection. One was a light covering favored by racers; the other was a rigid adaptation from other sports. Neither was universal, and both were quickly overtaken by later designs. They remain interesting as examples of how a safety product starts out as a niche, is shaped by materials and standards, and gradually becomes part of ordinary riding.