MIPS vs Non-MIPS Helmets

Buy MIPS if it costs an extra $20 or less, which it usually does. It is the only helmet feature we would actively spend money to get, and it is no longer a premium-only option — several helmets under $40 include it.

The more important thing first, because it reframes the whole category: every bicycle helmet sold in the United States has to meet the same federal safety standard. A $30 certified helmet and a $250 one pass the same impact and strap-retention test. So this is not a comparison between a safe helmet and an unsafe one. It is a comparison between a helmet that meets the standard and one that meets the standard and addresses something the standard does not test.

The difference, in seven rows

What the federal standard already guarantees

Since February 1999, every bicycle helmet manufactured or imported for sale in the US has had to meet a mandatory standard set by the Consumer Product Safety Commission and published as 16 CFR Part 1203. It requires, among other things:

• Adequate head protection in an impact— a specified drop test onto specified anvils.
• A chin strap strong enough to keep the helmet on during a crash. A helmet that comes off protects nothing.
• Extra coverage on helmets for children up to age five.

That is a real floor, and it is why we are comfortable recommending a $30 helmet. What the standard tests is a straight-line impact. What it does not test is what happens when you hit the ground at an angle.

What MIPS is designed to address

Real crashes are rarely a clean vertical drop onto the top of the head. You are moving forward at speed, so you hit at an angle, and an angled impact makes your head rotate suddenly.

Rotational motion is a common mechanism in concussion and more serious brain injury, because different parts of the brain move relative to each other and the tissue between them stretches. That mechanism is different from the straight-line deceleration the drop test measures.

MIPS puts a slip plane between the helmet liner and your head. In an angled impact the helmet can move a little instead of transferring all of that rotation into your skull. Mips describe the design as mimicking the brain’s own protective layer, which allows a small amount of movement inside the head.

Being honest about what we can and cannot say

We are going to be careful here, because this is a subject where confident claims are cheap and consequences are not.

What is well established: rotational motion is a recognized injury mechanism; the federal standard tests linear impact rather than rotation; and MIPS is specifically designed to reduce rotational transfer, with the manufacturer publishing the 10–15mm movement figure.

What we will not tell you: a percentage reduction in injury risk. We have not tested helmets, we do not own the underlying research, and any number we quoted would be someone else’s marketing repeated as if it were ours.

Where that leaves the decision: a mechanism that plausibly matters, addressed by a design intended to address it, for about $20. On those terms it is an easy yes — and that is the whole basis of our recommendation, stated plainly rather than dressed up as evidence we do not have.

The thing that matters more than either

Fit. A cheap helmet that fits properly is safer than an expensive one that does not, and this is not a slogan — a helmet that moves on your head is not in the right place when it is needed, and no internal slip layer compensates for that.

The four checks, briefly:

1. Level, not tilted back. Front edge two finger-widths above your eyebrows.
2. Snug before the straps. It should stay put when you shake your head with the chin strap undone.
3. Straps in a V just below each ear.
4. Chin strap tight enough to be slightly annoying. Open your mouth wide — the helmet should pull down.

Our helmet fitting guide covers all four properly, including how to measure your head and what to do between sizes.

Where we would actually spend

• Under $40: get MIPS. It exists at this price now, and there is no reason to skip it.
• $40 to $80: MIPS plus better ventilation and fit adjustment. This is the sensible band for most riders.
• Above $120: you are buying weight, ventilation and aerodynamics. Genuinely nice, and not safety. Put the difference into shorts or lights, which change more rides.

And the one rule with no exceptions: replace any helmet after an impact, and never buy a used one. The foam crushes to absorb energy and does not recover, and you cannot see whether a second-hand helmet has already done its job once.