Spin Doctors: How the Bike Industry Wants to Protect Your Head

Six angular impact mitigation systems, explained

Title photo: The Dome

Xerox. Kleenex. Google. Uber. MIPS? For a while, it seemed like the Swedish helmet technology brand was on its way to achieving the enviable position of its yellow plastics becoming synonymous with the entire market for angular impact mitigation products. Considering what a mouthful that term is, it’s not hard to see why.

MIPS also got off the line first—and enjoyed broad licensing from a slew of brands—but its head start has diminished in recent years. POC, Kali, Leatt, 6D and Bontrager all now have their own angular impact mitigation (AIM) technologies, each of which claims various benefits. At their most basic, these technologies are said to allow the helmet to rotate independent of the head. This may reduce the rotational forces that act on the brain during a crash—the same forces that have been linked to concussions.

Separating spin from science is important when it comes to these products, but that’s a larger and much more complicated story. For now, it’s pretty much impossible to get a clear comparison between the technologies. Even testing between AIM and non-AIM helmets are wrought with confounding variables like differences in methodology and our limited understanding of brain injury. So no, we are not going to tell you which is best because no one knows. In the meantime, let’s take a look at what each brand offers, and the benefits they claim.


MIPS Helmet Versus 1898
Photo Credit: The Dome
MIPS shown inside Giant’s Roost helmet. Photo: Ryan Palmer

You could think of MIPS like the Bernie Sanders of the AIM industry. Regardless of the fact that its competitors have developed similar alternatives, it deserves credit for having started the conversation. It’s received that credit in the form of 78 brand partners who have licensed its creations, speccing MIPS in 448 helmet models and resulting in over 9 million MIPS layers being produced (according to MIPS’ own count).

MIPS A1 Cronk
Photo Credit: The Dome
MIPS A1 pads. Photo: Satchel Cronk

You’ve probably seen a few of those 5 million yellow plastic bowls. At this point, you’ve probably even worn one. They attach to the EPS (expanded polystyrene) shell of a helmet via three to four elastomers. The MIPS layer is coated in a low-friction ink that improves its ability to slide relative to the EPS. MIPS claims that the float between the MIPS layer and the EPS shell reduces the rotational motion transferred to the brain.

The ‘bowl’ version of MIPS (technically called “MIPS-C2”) is only one of a few solutions the company now offers. Another is MIPS-A1, which is housed inside pads. Inside the pads, multiple plates with fabric layers between them create the movement that allows the helmet to float.


POC – Spin

Photo Credit: The Dome
“The Spin is IN the pads?” “It’s so simple.”

POC was first to market with a MIPS-equipped helmet, but has since moved on to a system of its own devise, though MIPS has questioned exactly how original the SPIN system is. It filed an intellectual property infringement against POC over the SPIN system, which the former partners have since settled. POC’s SPIN system is indeed similar to MIPS-A1. It might actually offer some advantages over MIPS’s system, though. The silicone-injected SPIN (Shearing Pads INside) pads are said to allow the EPS shell to rotate independent of the wearer’s head, but, unlike MIPS, are also said to help reduce linear forces.


Kali – Low Density Layer

A strip of Kali’s LDL is shown poking out from behind a pad in its Interceptor helmet. Photo: Jonathon Weber

The belief that helmets are too hard underpins Kali’s helmet technologies. Kali addresses rotational forces with what it calls the Low Density Layer, which is made up of strips of gel cups that almost look like octopus tentacles. The helmet pads are mounted on top of the strips, so that they float on the cups. In a crash, Kali claims that the cups can compress, rotate, and shear, meaning that, like POC’s Spin system, they help to reduce both linear and rotational forces. As with all these technologies, it’s hard to know how effective LDL is. But it seems like it worked for Nicholi Rogatkin…


Leatt – 360° Turbine

Leatt’s Turbines inside its DBX 2.0 helmet.

Leatt’s 360° Turbine Technology is right along the lines of Kali’s LDL and POC Spin. Instead of gel strips that sit underneath the pads or silicone injected into the pads, Leatt’s non-Newtonian Turbines sit directly against the wearer’s head, and, like those other two, are said to reduce both linear and rotational forces. I think I might be noticing a pattern here.


6D – ODS

6D’s ODS system consists of two EPS layers that float on elastomer dampers.

California-based 6D has one of the more unique AIM technologies. Its ODS (Omni-Directional Suspension) system consists of two separate EPS shells connected by elastomer dampers that permit the shells to float, rotate and compress independent of each other. 6D claims that the system offers superior performance in both low- and high-force impacts. We can’t verify those claims, but we can tell you that these helmets are big and heavy.


Bontrager – WaveCel

Like Koroyd, WaveCel is a cellular structure that supplements traditional EPS. Unlikle Koroyd, it is said to help mitigate rotational forces. Photo: Bontrager

Bontrager has been licensing MIPS for use in its helmets for a while now, but it recently launched helmets with a new licensed technology called WaveCel. Like the honeycomb-esque Koroyd layers in Smith’s helmets, WaveCel is a cellular structure that supplements the traditional EPS shell. Unlike Koroyd, though, which is only supposed to mitigate linear forces, WaceCel is said to be able to rotate and shear as it compresses, so that it can mitigate both linear and rotational forces. You can get the full scoop on WaveCel in this post.

But it hasn’t been an easy start for the new kid on the block. MIPS and Koroyd quickly circulated press releases calling foul on one of the studies cited by Bontrager to support its performance claims. Among the reasons to be skeptical include the study’s admission that two of its authors are co-inventors of WaveCel and have a financial stake in its success. There were also some unusual methods used in the study, though, again, there is no current standard for testing angular impact mitigation. Still, all of Bontrager’s WaveCel helmets have received high ratings from Virginia Tech’s rating program, so their performance in those tests is at least as good as some MIPS models.


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