MIPS (Multi-directional Impact Protection System) is a thin, low-friction layer inside a helmet that lets the shell rotate a few millimetres relative to your head during an angled impact. That small slip reduces the rotational forces transmitted to your brain, which research links to concussion. It adds around 20-30 g and a modest cost premium - and for most riders, it is worth it.
When you crash, chances are the helmet does not hit the road at a perfect right angle. The impact is oblique - the shell strikes and slides, transferring both linear force and a rotational twist to your head. MIPS was designed specifically for that second part. The liner and shell can slip a few millimetres against each other, dissipating some of the rotational energy before it reaches your skull.
Our research desk dug into the peer-reviewed biomechanics, the Virginia Tech STAR ratings, and the growing list of rival technologies to give you an honest picture of what MIPS does, what it does not do, and when the premium is justified.
How does MIPS actually work?
A conventional helmet bonds the EPS foam liner directly to the outer shell. In an angled impact, that rigid connection means any rotational force goes straight through to your head. MIPS inserts a low-friction slip plane - a thin polymer layer - between the liner and the head. Think of it as two surfaces that can slide past each other rather than locking together.
In a real crash, the slip is small: roughly 10-15 mm in any direction, enough to last 10-15 milliseconds. That window is all the system needs to decouple the shell's rotational jerk from your brain. MIPS AB (the Swedish company that developed the technology) has published brain model simulations showing meaningful reductions in strain on brain tissue for oblique impacts at angles typical of real crashes.
One important caveat: no independent certification body currently has a pass/fail rotational-protection standard. Virginia Tech's STAR ratings score helmets on both linear and rotational metrics and give one of the most useful comparative benchmarks available, but MIPS is an input to a score, not a badge of its own. The fact that many MIPS helmets land in the top tiers of STAR ratings is telling, even if causation is complex.
Why rotational force is the part that causes concussion
Linear impacts - straight blows to the head - compress the brain against the skull and cause focal injuries. Rotational acceleration is different: it causes the brain to twist relative to the skull, stretching axons and producing the diffuse injury pattern associated with concussion and traumatic brain injury.
Research from the Karolinska Institute and others (including work by Hans von Holst, one of MIPS's founders) showed that even moderate rotational accelerations can exceed the brain's injury threshold. The key point is that most real-world crashes involve oblique impacts - a rider going down at speed rarely hits the road perpendicularly - so linear-only protection misses a significant chunk of the risk.
The honest counter-argument: your scalp and hair already provide some natural slip between your head and the liner. Critics argue the 10-15 mm MIPS slip plane does not add much on top of that. MIPS's published data and the STAR ratings suggest it does make a measurable difference, but the effect is not as dramatic as the marketing implies.
What bike helmets have MIPS, and what does it cost?
MIPS is now licensed to more than 130 helmet brands and appears across road, mountain, commuter, kids, and multi-sport helmets. You will find it from budget options around $40-50 up to top-tier race helmets over $300. The premium over the non-MIPS version of the same helmet is typically $10-30 and 20-30 grams of added weight - small concessions by any measure.
For cycling specifically, look for the MIPS logo (yellow circle) on the retention dial, the box, or the inside of the liner. Brands including Giro, Bell, POC, Specialized, Trek, Bontrager, Smith, and Giant all offer broad MIPS ranges. At the budget end, our budget MTB helmet picks include several MIPS options that test well in the STAR system without breaking the bank.
For higher-risk disciplines - EUC (electric unicycle), onewheel, and similar - rotational protection matters even more because falls tend to be abrupt and unpredictable. Our EUC helmet guide and onewheel helmet guide both prioritise helmets with MIPS or equivalent rotational tech.
The honest debate: is MIPS worth it?
The case for MIPS is straightforward: biomechanical evidence supports reducing rotational acceleration, the cost and weight penalty is minor, and the Virginia Tech STAR data show that helmets with MIPS tend to score better than their non-MIPS counterparts. For the modest premium, the risk-reward maths favour it.
The case against - or at least the honest sceptic's position - is that: (1) no standard independently certifies rotational protection, so you are partly trusting the manufacturer's models; (2) your scalp already provides a natural slip plane, potentially reducing MIPS's marginal benefit; (3) a well-constructed helmet without MIPS may score better in STAR than a poorly constructed helmet with it. The system is only as good as the base helmet design.
Our take: for most riders - road, trail, commute - the MIPS premium is a reasonable small bet on a technology with credible science behind it. It is not magic. A well-fitting, well-certified non-MIPS helmet still vastly outperforms an ill-fitting MIPS helmet, because choosing the right bike helmet and getting the fit right is the foundation that everything else builds on.
Alternatives to MIPS: WaveCel, KinetiCore, Koroyd, 6D ODS, SPIN
MIPS is not the only approach to rotational protection. A few competing technologies take a different mechanical route to a similar goal - decoupling the shell from the head or absorbing rotational energy within the liner itself.
- WaveCel (Trek/Bontrager) - a collapsible cellular structure that flexes and glides during an impact rather than using a separate slip layer. Trek claims it reduces concussion risk more than EPS+MIPS based on their own simulations; independent STAR data are mixed.
- KinetiCore (Lazer) - foam pillars moulded directly into the EPS that rotate and compress during impact, eliminating the separate MIPS layer. Lighter and integrated, but fewer third-party test data points so far.
- Koroyd - a welded polymer tube structure used in place of or alongside EPS, offering both linear and some rotational energy management plus better ventilation. Seen in Smith and Scott helmets.
- 6D ODS (Omni-Directional Suspension) - twin-shell design with elastomeric dampers connecting inner and outer shells, allowing movement in all directions. Popular in MTB and moto; heavier and more expensive.
- POC SPIN - silicone pads bonded to the liner that shear during impact. POC phased this out in favour of MIPS licensing for most 2024+ models, which is itself a data point about which technology they back.
Rotational protection technologies compared
| Technology | How it works | Found on | Notes |
|---|---|---|---|
| MIPS | Low-friction polymer slip plane between liner and head; 10-15 mm rotation in any direction | 130+ brands (Giro, Bell, POC, Specialized, Trek, Smith, Giant) | Most STAR-tested data; modest weight/cost premium; no independent pass/fail standard |
| WaveCel | Collapsible cellular liner flexes and glides on impact | Trek / Bontrager exclusively | Manufacturer simulations promising; STAR results vary by model |
| KinetiCore | Rotating EPS pillars integrated into foam; no separate layer | Lazer helmets | Lighter than MIPS; limited independent test data (growing) |
| Koroyd | Welded polymer tubes absorb and manage energy; used with EPS or alone | Smith, Scott, Poc (some) | Good ventilation benefit; often paired with MIPS |
| 6D ODS | Twin-shell with elastomeric dampers; omnidirectional movement | 6D brand (MTB, moto focus) | Widest range of motion; heavier and premium-priced |
| POC SPIN | Silicone shear pads bonded to liner | Older POC models (pre-2024) | POC has largely moved to MIPS licensing for current lineup |
DOT vs ECE vs Snell vs MIPS, how to pick the right lid in 60 seconds, and when to replace it. One page, no fluff.
Frequently Asked Questions
What is MIPS in a bike helmet?
MIPS (Multi-directional Impact Protection System) is a thin low-friction layer between the helmet shell and the liner. In an angled impact, the two surfaces can slip 10-15 mm against each other, reducing the rotational force transmitted to the brain. It was developed by Swedish researchers studying how oblique impacts cause concussion.
Does MIPS actually prevent concussion?
The biomechanical evidence supports it in principle: rotational acceleration is a primary driver of concussion, and MIPS reduces that acceleration in lab simulations. Virginia Tech STAR ratings back this up for many MIPS helmets. It is not a concussion guarantee - no helmet is - but the technology has credible science behind it and a small cost/weight penalty.
How much does MIPS add to a helmet's price?
Typically $10-30 over the non-MIPS version of the same helmet. Some brands absorb the cost and charge the same price. The weight penalty is usually 20-30 grams. Given the evidence base, most riders find that a reasonable premium.
Is MIPS better than WaveCel or KinetiCore?
No single technology is definitively best. MIPS has the largest body of independent test data (Virginia Tech STAR ratings). WaveCel shows promise in manufacturer-funded simulations. KinetiCore is newer with fewer data points but lighter. The base helmet design and fit matter more than which rotational-protection technology is used - a top-rated MIPS helmet in the wrong size protects less than a mid-tier helmet that fits correctly.
I bought a helmet without MIPS. Should I replace it?
Not necessarily. Knowing how to wear and fit a bike helmet properly, plus certification (ECE 22.06, Snell, or CPSC/ASTM depending on your activity), comes first. If your helmet fits well, carries a current certification, and has not been crashed, it is still doing its main job. MIPS is a meaningful upgrade on your next purchase - not a reason to bin a serviceable helmet that fits properly.
