Cheap vs expensive bike helmet: what’s the difference?

A Specialized Align II cheap helmet next to a Prevail III expensive helmet
(Image credit: Specialized)

You can find bike helmets for $30, and you can find bike helmets for $300. Given the fundamental reason for purchasing one is to look after your head, it would be easy to assume that as you pay more, you’ll benefit from increased protection. However, this isn’t strictly true. What's the difference between cheap and expensive bike helmets, then?

In the EU and UK, helmets must conform to the EN1078 safety standard. In the USA, they have to meet the Consumer Product Safety Commission’s CPSC 1203 standard. Both these specify critical elements of the helmet’s design, including a minimum field of vision, shock absorbing properties, and the function of its retention system. They also mandate how the helmet will be tested and the results it must achieve.