By The Takeaway: A high-end mountain bike helmet with exceptional ventilation and enhanced protection.
• MIPS Spherical with and two foam densities for energy redirection and absorption.
• Giro’s best ventilated mountain bike helmet, and also its most expensive.
• New Roc Loc Trail Air fit system is less fragile than Giro’s previous designs.
• Sold in three sizes—small, medium, large—and six colors.
Price: $260
Weight: 362g (medium)
Giro’s new $260 Manifest mountain bike helmet is the brand’s most expensive half-shell to date. At a full $100 more than the excellent Montaro, the Manifest is a lightweight trail helmet with some interesting safety technology and claimed best-in-class ventilation.
Fidlock Buckle
The magnetic Fidlock buckle connects quickly and easily.
Two Shells
The Manifest has a softer inner shell, and a harder outer shell.
Height Adjustment
Three height positions for the Roc Loc fit system.
Padded Roc Loc
Padding on the occipital gripper enhances comfort.
Reinforcement
A polyamide reinforcing ring improves structural integrity in a crash.
The Manifest employs Giro’s twin-shell energy-redirection system. This system debuted with the Aether road helmet and later came in the Tyrant enduro helmet. Previously Giro called this technology MIPS Spherical, but for reasons that probably involves some lawyers debating intellectual property, the company calls the Manifest’s system “Spherical Technology, powered by MIPS.”
New Levels of Comfort, Cooling, and (Maybe?) Protection
Despite the clunky name, the Spherical technology is very good. It replaces the familiar plastic MIPS liner inside the helmet with a design consisting of two nested and linked shells—Giro calls it “ball-and-socket”—that can move independently. The concept is the same as a MIPS liner—a slip plane redirects energy in some impacts to reduce impact forces—but the slip plane no longer sits inside the helmet against your head. It’s now hidden between the two shells.
This gets rid of the plastic liner, which can snag your hair and squeak annoyingly, and allows Giro to use a different foam density for each shell. The outer shell is a higher density foam, which performs better (than lower-density foam) in high-speed impacts. The inner shell employs a lower density foam that protects better in lower-speed impacts.
The Manifest’s outer shell employs a polyamide reinforcing ring, which improves the helmet’s structural integrity in an impact, Giro says. That added strength allowed Giro to create larger vents for better cooling while still passing necessary safety tests, said Dain Zaffke, Giro’s marketing director.
A harder question to answer is whether Spherical tech is demonstrably “safer” than traditional MIPS? It’s difficult to test (not a lot of humans are lining up to have their brains monitored during simulated crashes), and just as hard for brands like Giro to answer without getting in legal hot water.
Here’s what Giro’s spokesperson Peter Nicholson told me when I asked, “Spherical allows [Giro] to create a helmet that meet or exceeds all their internal testing, MIPS’s internal testing, and relevant certification standards while being lighter, cooler, and more comfortable than a helmet with a plastic MIPS liner.”
Giro submitted a Manifest for evaluation by Virginia Tech, which conducts leading helmet evaluations. The score and rating are not yet available (we’ll update this piece when they are), but Nicholson said, “It’s our understanding it did very well.”
A Very Impressive Helmet
I’ve been riding in a Manifest since early January, giving time to evaluate it and compare it with other trail helmets. It is a very impressive helmet, as it should be for the price.
The ventilation is no joke. Air flow is noticeable even at lower speeds, which is not something I can say about almost any other helmet. At trail speeds, the air flow is certifiably remarkable. Even when speeds aren’t high enough to generate flow, the Manifest breathes very well, with no sensation of hot air trapped against the skull. I’m the guy on the ride sweating before anyone else; I’m the guy who at the top of the climb looks like he rode through a rainstorm when everyone else looks dewy. Good ventilation is something I’m attuned to and prize and the Manifest is the best ventilated mountain bike helmet I’ve ever sampled.
On the subject of comfort, the Manifest also scores extremely high with me. It is almost luxurious—the plush padding feels nice on the skin, there’s a nicely padded occipital gripper unit, and smooth, supple straps. The magnetic Fidlock buckle is simple, fast, and secure, and the fit system’s dial is easy to find and adjust. The Manifest also works well with a variety of eyewear, with good clearance for models with different temple sizes and shapes. Add in its light weight and cooling power, and you have a very nice helmet in which to spend a lot of time.
I should note that I have a Giro-shaped head, so its helmets almost always fit me well. If you’ve tried on a Giro recently and it didn’t fit you, the Manifest probably won’t either.
But Not 100 Percent Perfect
The Manifest is not perfect—no product is—and I did run into a few things I didn’t love. The Manifest isn’t a great helmet for stashing eyewear in its vents, even though it was made to accommodate sunglasses up there. I also sampled the Manifest with goggles—there is an integrated strap gripper—and found that goggles with larger frames like Giro’s Blok are too large to stash under the visor, but medium-frame (and smaller) goggles dock well.
I found the visor a bit short for my conditions in southwest Colorado (lots of sun, lots of open sky). If the sun was anywhere but directly overhead, the Manifest’s visor doesn’t offer much coverage. To be fair, I have this issue with many visors. The reality is visor size and shape are driven at least as much—and probably more—by style than they are by function. The Manifest is positioned as a lightweight trail helmet, and that dictates a sleek shape—it won’t get a honkin’ enduro-sized visor.
A note: The Manifest does not have an integrated mounting system. Giro considered one but, “[We] found that pro riders using Switchblade and Montaro, both with camera mounts, ended up choosing a different spot for their cameras at least half the time,” Nicholson said.
Since I began testing the Manifest in January, I’ve been able to compare it to other popular mountain bike helmets. There’s no question the Manifest is very expensive—though it is $40 less than Bontrager’s Blaze WaveCel—and there is a long list of very good helmets that cost much less than a Manifest. But the Manifest’s comfort and cooling is currently unmatched—this is a superb helmet. If it fits, and you’re willing to pay for it, you’ll love this helmet.
Pros
- Superb ventilation
- Very comfortable
Cons
- Some eyewear difficult to stash in vents
A gear editor for his entire career, Matt’s journey to becoming a leading cycling tech journalist started in 1995, and he’s been at it ever since; likely riding more cycling equipment than anyone on the planet along the way. Previous to his time with Bicycling, Matt worked in bike shops as a service manager, mechanic, and sales person. Based in Durango, Colorado, he enjoys riding and testing any and all kinds of bikes, so you’re just as likely to see him on a road bike dressed in Lycra at a Tuesday night worlds ride as you are to find him dressed in a full face helmet and pads riding a bike park on an enduro bike. He doesn’t race often, but he’s game for anything; having entered road races, criteriums, trials competitions, dual slalom, downhill races, enduros, stage races, short track, time trials, and gran fondos. Next up on his to-do list: a multi day bikepacking trip, and an e-bike race.
