Leatt DBX 4.0 Full Face Mountain Bike Helmet Makes DH Riding Safer and Less Sweaty [Review]

The Leatt DBX 4.0 is a lightweight and heavy protection full-face mountain bike helmet that doesn't leave you as sweaty as some.
leatt dbx 4.0 helmet
Photo: Matt Miller

My buddy pulled up alongside of me at a pull-off on a downhill trail and gave me a disappointed look. “Man, wearing a full-face sure does give you a lot more confidence. Wish I’d brought mine today.”

I hadn’t thought about it much as these days it feels instinctual to bring a full-face helmet to the bike park. Even if I’m taking it easy, chances are that I’ll still be going pretty fast and I don’t need to worry about ventilation as much, so it just makes sense.

Some days, a full-face helmet might seem like overkill, even at a bike park, but it only takes one crash, and I have seen friends mis-land on jumps at the same park before and end the day with a bloodied face and a concussion.

Leatt dropped the new DBX 4.0 around Interbike time last year in September. They handed one off to me a few months ago and I’ve logged enough hours inside of it to know it’s light and comfortable.


leatt dbx 4.0 helmet
Photo: Matt Miller.
  • Polymer compound shell
  • Removable mouthpiece
  • 360-Deg. Turbine Technology (rotational impact reduction)
  • In-molded EPS and EPO impact foam
  • 22 vents total
  • Fidlock magnetic buckle
  • Washable and removable interior padding
  • Breakaway visor
  • Certifications: AS/NZS 2063:2008, ASTM F1952–10, EN1078, CPSC 1203
  • Comes in S, M, L, XL sizing
  • Weight: 840g (size medium tested)
  • MSRP: $230

Buy It: from $229 at Jenson USA

Compare Prices: Leatt DBX 4.0 Full Face Helmet 2019 

About the Leatt DBX 4.0 and ride impressions

Helmets like the Leatt DBX 4.0 are being made lighter and lighter with more strategic venting, more material in the right places, and less material where it needn’t be. Other lightweight full-face helmets like the Fox Pro Frame and Bell Super DH (which we tested) come to mind as minimalistic shells for maximum protection.

The DBX 4.0 comes with a plethora of certifications and Leatt’s web page includes all of the appropriate testing and research literature. 

The Fidlock buckle and Leatt 360-deg. Turbines. Photo: Matt Miller.

Like other Leatt helmets, the DBX 4.0 comes with the little blue Turbine discs placed around the inside of the skull area. The Turbine discs are made of an impact-resistant material that hardens on impact and moves in any direction to reduce rotational impact. Read more about the technology here.

Photo: Matt Miller.

There are also little red pull tabs on the bottom of the cheek pads to pull away in the case of an emergency. Likely, the rider wouldn’t be the one pulling them out.

leatt dbx 4.0 helmet
That mouth guard easily pops in and out of place. Photo: Matt Miller.

There is a removable mouth piece on the helmet to make hydration easier and the Fidlock magnetic buckle is all about convenient snapping. It’s not full-proof and can still take some fidgeting, but is miles easier to figure out than the D-ring closure on other helmets while your hands are gloved, and a bit easier than a snap buckle.

The mouth piece is a convenient feature. Usually when I ride the bike park I have a bottle on me and it’s always a little tricky to try and stick the bottle under the helmet and tilt it back. The mouth piece makes it easy to pop that bottle in and hydrate while riding the chair lift.

Photo: Hannah Morvay.

The front of the Leatt DBX 4.0 seems to press on my forehead more heavily than other parts of the helmet, but otherwise, it fit well around my head.

It’s easy to don the DBX 4.0 for hours on end in the bike park. Its lightweight structure and heavy ventilation make wearing the extra measure of protection much more pleasurable and forgettable. Even on warm days, I lifted the DBX 4.0 off my head to find only a light amount of sweat in my hair.

Final word

Photo: Hannah Morvay.

The Leatt DBX 4.0 is a mark of progression in the world of full-face helmets. It is light, looks great, and is backed with all the certifications that give buyers the assurance that it is money well spent.

Check out our mountain bike helmet buyers guide and our picks for the best mountain bike helmets.

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