A MIPS helmet is any helmet equipped with the Multi-directional Impact Protection System, a low-friction liner designed to reduce rotational forces on your brain during a crash. The technology adds a thin plastic layer inside the helmet that slides slightly on impact, redirecting the twisting energy that standard helmets don’t address. MIPS helmets are available across cycling, skiing, motorcycle, and equestrian sports, typically adding $15 to $30 to the price of a comparable non-MIPS model.
Why Rotational Force Matters
Traditional helmets are built to handle straight-on impacts. They use a foam layer (usually expanded polystyrene) to absorb the force of your head hitting a hard surface directly. That foam does an excellent job of preventing skull fractures and reducing the kind of acceleration that comes from a head-on collision. But most real-world crashes don’t send force straight into your skull. They involve an angled hit, which makes your head rotate sharply inside the helmet.
That rotation is the problem MIPS targets. When your head twists rapidly on impact, the brain, which sits in fluid inside the skull, lags behind. This creates shearing forces that stretch and distort brain tissue. Research from the National Highway Traffic Safety Administration confirms that rotational velocity is the best predictor of dangerous strain levels inside the brain. Linear acceleration alone doesn’t produce high internal brain strain, but rotation does, and it does so efficiently. This shearing mechanism is closely linked to concussions and more severe diffuse brain injuries.
How the Slip Plane Works
Inside a MIPS helmet, a thin plastic liner sits between your head and the helmet’s foam. This liner is attached to the helmet shell at specific anchor points but is free to move in all directions by roughly 10 to 15 millimeters. When your head hits the ground at an angle, the outer shell and foam grip the surface and want to stop, but the inner liner slides independently, allowing your head to rotate slightly relative to the helmet.
That small movement takes a fraction of a second, but it’s enough to redirect some of the rotational energy away from your brain. Think of it like the way your scalp naturally slides over your skull if you bump your head. The slip plane mimics that natural movement. The result is lower peak rotational acceleration reaching the brain, which translates to less tissue shearing.
What Standard Helmets Don’t Test For
The U.S. Consumer Product Safety Commission standard for bicycle helmets (16 CFR Part 1203) requires helmets to pass tests for impact absorption, retention system strength, positional stability, and peripheral vision. The impact test drops a helmeted headform onto flat, hemispherical, and curbstone anvils and measures peak linear acceleration, which cannot exceed 300 g. None of these tests measure rotational forces. The standard doesn’t require any rotational acceleration testing at all.
This means a helmet can pass every required safety test and still offer no protection against rotational brain injury. MIPS testing is entirely voluntary and conducted by the MIPS company itself using its own angled-impact test rigs. Several independent labs, including Virginia Tech’s helmet rating program, also evaluate rotational performance, but these are rating systems rather than legal requirements. A helmet without MIPS (or a competing anti-rotation system) isn’t violating any safety standard. It simply isn’t addressing a force that current regulations ignore.
Different MIPS Versions
Not every MIPS helmet uses the same design. The company offers several versions of its system, each integrated differently depending on the helmet’s price point and intended use.
- MIPS (standard): The original yellow plastic liner visible inside the helmet. It’s the most common version and appears in helmets across all price ranges.
- MIPS Evolve: A refined version with improved fit, better ventilation, and lighter weight compared to the standard liner.
- MIPS Integra: Built directly into the helmet’s impact-absorbing foam layers rather than sitting as a separate liner. It’s nearly invisible inside the helmet and is one of the lightest MIPS options.
- MIPS Air Node: The lightest and most comfort-focused system. It’s integrated into the helmet’s padding itself, making it almost undetectable when you put the helmet on.
From a safety standpoint, all versions serve the same function. The differences are primarily about weight, airflow, and how noticeable the system feels on your head. Higher-end helmets tend to use Integra or Air Node because those versions don’t compromise ventilation or add perceptible bulk.
MIPS vs. Competing Technologies
MIPS isn’t the only approach to rotational protection. Several helmet brands have developed their own systems. Bontrager’s WaveCel uses a collapsible cellular structure that flexes on angled impact. POC’s SPIN system uses silicone pads at key contact points that shear on impact, achieving a similar sliding effect. Leatt and 6D use different internal suspension designs. Each claims to reduce rotational forces, and each uses a different mechanical approach to do it.
MIPS has the widest adoption because it licenses its technology to over 120 helmet brands rather than manufacturing helmets directly. That means you can find MIPS in helmets from Giro, Bell, Smith, Troy Lee Designs, Scott, and dozens of others. If a helmet includes MIPS, it will have a small yellow MIPS logo on the exterior and the characteristic yellow liner visible inside.
What You’ll Notice Wearing One
A MIPS helmet feels almost identical to a non-MIPS version of the same model. The standard liner adds roughly 20 to 30 grams, which is unnoticeable on your head. Some riders report that the plastic liner slightly reduces airflow in helmets with large vents, but the newer Integra and Air Node versions eliminate this issue entirely. When you put the helmet on and shift it with your hands, you can feel the shell move slightly relative to the liner. That’s the slip plane doing what it’s designed to do.
The fit system works the same as any helmet. You still adjust the dial or straps to get a snug fit. The MIPS liner doesn’t change sizing, so if you normally wear a medium in a particular brand, you’ll still wear a medium in the MIPS version.