I’ve been spending time in a number of MIPS trail helmets recently, so a comparison is in order. While MIPS was a somewhat rare feature in helmets a few years ago, it is now found in plenty of higher-end helmets these days. And with the price of MIPS helmets dropping quickly, the argument for picking up a MIPS lid is getting even stronger. So here’s a small sampling that I’ve ridden in — I have at least eight rides in each of these helmets, in conditions ranging from hot and humid to cool and dry.
First, though: Why should you consider a MIPS-equipped helmet?
The Case for MIPS
MIPS helmets have two things working against them vs. their non-MIPS counterparts: (1) they cost more, and (2) I find that they tend to run a little hotter. So is it worth it? My take is that, yeah, it is.
Traditionally, helmets have been designed to deal with linear impacts. In a linear impact, your head runs straight into something, and, to put it in technical terms, your brain sloshes up against the inside of your skull. That’s bad.
The way helmets protect against that is by slowing down the impact by fractions of a second. By slowing down the impact, your brain decelerates more gently and sloshes less. The vast majority of bike helmets are made out of expanded polystyrene foam (EPS), the reason being that EPS does a really good job of handling direct blows. When you smash your helmet-shod head straight into a tree, the EPS crushes, breaks, and does a pretty damn good job at dissipating the force of the impact. And EPS does that in a package that’s light, relatively cheap, and easy to work with.
But bike crashes are rarely that simple — plenty of crashes aren’t limited to the one dimensional impacts that EPS protects well against. Lots of crashes involve glancing blows, which introduce rotational forces. This is where MIPS comes in.
With a rotational force, instead of your brain sloshing against the side of your skull, it’s rotating within it. Your skull rotates rapidly, but your brain can’t keep up. Somewhere in the background, Newton mumbles something about his first law. As with linear impacts, this is a bad thing.
The MIPS system is essentially a slip plane within the helmet that allows the outer shell of the helmet to rotate independently from the inner liner and your head. In turn, this reduces and slows the rotational forces on your head.
There is general consensus that rotational impacts are a problem, and most scientifically-minded people agree that a slip plane like MIPS is one way to address those rotational forces. Some detractors argue that the MIPS system doesn’t really serve any purpose that isn’t already addressed by the natural ability of a helmet to rotationally slip on the scalp or hair. My entirely unscientific take on the matter is that, while helmets can rotate without MIPS, the MIPS system is better for a couple of reasons:
Compared to a non-MIPS helmet, a helmet with the MIPS system seems to retain its ability to rotationally slip even in better fitting, tighter helmets. It also allows the helmet to slip even when I’m pressing the helmet firmly down on my head (as might happen in a crash), and it allows a bit more rotational slip than the helmet could have if it was just slipping on my hair. Perhaps more importantly, the “slippiness” is controllable; the rotation allowed by the MIPS system is engineered into the helmet, while the amount a helmet can rotate on hair and skin will inevitably vary a lot from person to person, and somewhat depends on helmet fit.
Long story short: my take is that there is a tangible benefit from the MIPS system in certain kinds of crashes. And if nothing else, given that the cost of the MIPS system has come down a lot recently and manufacturers are getting better about ventilation with MIPS, the downsides are pretty minimal.
[For more on MIPS and helmet technology, check out our podcast with Sr. Director of R&D at Giro, Rob Wesson, and our podcast with Ståle Møller, the lead designer and co-founder of Sweet Protection.]
When I’m looking at helmets, there’s a number of factors that I’m considering. In rough order of importance:
Fit: Fit is pretty much the most important factor when buying a helmet. The whole point of a helmet is to keep you from vegetablizing yourself, and a good fit is key to a helmet working properly. Helmet fit is obviously specific to everyone’s individual head, so if possible, try before you buy. I’m also looking at overall comfort in this category — are there weird pressure points, or does the helmet nicely wrap around my head? For reference, all of the helmets I tested were a size Medium.
Protection: This is a tough one. Obviously, the whole point of a helmet it to protect your head, so I want a helmet that does a really good job. The tough part is that there isn’t a great way to independently assess this since most companies don’t publish the results of their certification testing (Leatt is the only helmet company I know of that publishes their results). Of the protection features that I can assess without investing in some really expensive equipment, I’m looking at how much coverage the helmet offers, particularly in the back, and whether there are any specific features to improve protection. One such protection feature is obviously MIPS, which all of these helmets have.
Head Retention System: Pretty much every modern helmet has some sort of system to keep the helmet stable on your head, but some are better than others. I’m looking at adjustability, the ability to fit a variety of head shapes and hair styles, and overall retention and comfort.
Ventilation: Hot helmets suck. More ventilation is good, but is potentially a trade off with protection. I find that bigger vents work better at low speeds, whereas lots of little vents work better at higher speeds.
Sweat Management: Regardless of how well ventilated a helmet is, I’m still going to end up sweating in it. Does the helmet channel all of that sweat directly into my eyes, or does it find somewhere more helpful to put it?
Straps: Some helmets have straps that are too short, some are too long, and some find other new and unique ways to suck.
Visor: A bad visor is one I notice. The best visors are adjustable and replaceable.
Gadgets: Does the helmet have integration for lights, POV cameras, goggle straps, sunglasses, or other knick knacks?
Certifications: Certifications are near the bottom for importance? Yup. Because certifications like the CPSC in America are a minimum bar – every helmet on the market has to pass them. All of the helmets in this test pass the usual assortment of certifications, and if you come across a helmet that doesn’t pass, don’t buy it; it’s as simple as that.
Looks: Ok, putting this at the bottom of the list is a bit is perhaps ignoring realities a bit. We all want to look “hella fly,” but for a helmet (more than most things), form should follow function.
Price: This is most definitely not the least important criteria, but how much it matters really depends on you, the buyer. Look at how the helmet performs in all other respects and then decide if it’s worth it to you.
NEXT: The Helmets