MIPS Bike Helmet or WG11 Bike Helmet? The Difference Explained

The first bike helmets were anything but safe — or comfortable, for that matter. Padded leather "hairnets" constituted a safety move by a cyclist in the 1970s. Then SNELL ratings for bike helmets finally moved the needle toward an actual bike helmet that, you know, protected cyclists and saved lives. Bell introduced its first bike helmet in the mid-1970s, a model that featured a molded plastic shell with a styrofoam liner to absorb impact. Every helmet since has spun off from that original prototype.

In 1984, ANSI codified safety standards for bike helmets in the U.S., which have remained relatively unchanged. By the 1990s, the modern bike helmet was established. It features a thin, hard plastic shell and an expanded polystyrene (EPS) foam liner. For the next two decades, the push to design lighter, more ventilated, and more aerodynamic helmets — that meet ANSI standards — continued. 

What Is a MIPS Bike Helmet?

But there was a problem with the ANSI-rated helmets or, more specifically, with the ANSI standards. These helmets had one job: to prevent a crash from cracking your skull open — an injury usually resulting from a direct impact. The problem is that most bike crashes and falls occur at speed, with the head hitting the ground at an angle and sliding or twisting on contact with the ground or other objects (like a tree, boulder, or car).

These real-world crashes cause rotational shearing forces on the brain, which could lead to concussions and other significant brain trauma. Fortunately, experts were thinking about it in the early aughts. The MIPS system, or Multi-Directional Impact Protection System, was inspired by the brain’s natural shock absorber, the cerebrospinal fluid that surrounds the brain. A helmet with a MIPS system features a layer between the hard outer shell and the EPS foam liner. Upon a side or angled impact, the MIPS liner allows for 1-1.5 cm of 360-degree movement, significantly reducing the impact forces reaching your brain.

Since roughly 2010, hundreds of helmet brands across the globe have incorporated MIPS liners into their helmet designs. Other brands have developed proprietary solutions for protection from rotational impact forces. And science has shown that the tech works. A 2021 study from Frontiers in Bioengineering and Biotechnology, which compiled all available research on bike helmet safety, found that the new technology backs up its safety claims. Helmets that protect against rotational impact forces are significantly safer than helmets without. However, the study concluded with the need to set international safety standards for rotational impacts, much like it has for direct hits.

No Safety Standard for Rotational Impacts Creates Confusion

Into this arena came the WG11, a European body that finds the MIPS concept valid but disagrees with how MIPS conducts its testing. In short, the difference comes down to the head form used. MIPS uses a Hybrid III head shape — the same one used on vehicle crash test dummies. The WG11 group considers the Hybrid III an unrealistic head form that doesn't mimic the impact forces on a human head. Instead, the WG11 test uses the EN 960 head form, recently adopted in Europe as the head form standard for motorcycle helmet safety tests.

This new standard is why Rudy Project helmets must pass WG11 testing standards for rotational forces, even if they feature MIPS liners. The WG11 rating means that the Rudy Project helmet line, which already exceeds international direct impact safety standards, offers wearers the next level of safety assurance.

The Future of Bike Helmets

From styrofoam to EPS foam to MIPS liners, bike helmets are slowly but assuredly getting safer, lighter, and more comfortable. The next frontier might be a helmet’s outer hard shell. Scientists in Singapore have developed a proprietary resin and carbon fiber shell called Elium. Upon impact, the Elium shell cracks, absorbing impact energy and reducing the total force reaching the helmet's EPS foam liner from 75 percent to 35 percent, according to Elium’s developers. If true, the result could be future helmets with thinner EPS foam liners that are more aerodynamic and sleeker than current lids but still offer exceptional protection.