Leatt MTB 4.0 Helmet – Review

The Leatt MTB 4.0 is a vented, full-face mountain bike helmet that offers both comfort and added protection.
Photos thanks to Emma Whittaker

I am someone who avoids wearing a full-face helmet until it is absolutely necessary. I have often ridden in bike parks and on challenging trails with my normal half-lid on. This probably comes from the fact that I tend to find most full-face helmets heavy, hot, and sweaty.  The Leatt MTB 4.0 is potentially aimed at riders like me who are averse to donning a full-face. 

Leatt’s MTB 4.0 helmet, also known as DBX 4.0, is part of a growing trend of full-face lids like the Fox Proframe or the Troy Lee Designs Stage that are somewhat better ventilated than traditional helmets. Leatt states that this new helmet is designed for downhill and enduro riding. With 22 vents, an 850g weight for the size medium tested and a removable mouth piece, it certainly gets off to a good start in that regard. 

Out on the trail, the helmet feels much more breathable than a conventional full-face helmet. It is slightly heavier than the Fox Proframe (by roughly 100g) or the Troy Lee Stage (by about 200g), but not in any noticeable way. As a matter of fact, I found the Leatt 4.0 helmet felt a little bit sturdier and more secure than some of the competition along those lines. Which, given the nature of the riding this helmet is intended for, is no bad thing. 

Leatt DBX 4.0 Helmet 360 turbine technology
360 Turbine Technology

All of the Leatt helmets use their ‘360 Turbine Technology’, which effectively consists of small disks inside the helmet which harden on impact, deflecting and protecting against linear acceleration. This technology appears to be comparable with the more well known MIPS technology, at least in terms of the desired outcome, i.e. reducing rotational acceleration on impact.

The helmet comes with other useful features too. For example, the front cheek pads can be removed in emergencies or for a long uphill pedaling section where you want a bit more comfort. Also, the visor is designed to break away in a crash to minimize the risk of additional rotational forces. 

For someone who doesn’t usually like riding in a full-face, I have really enjoyed riding in this one. It is surprisingly breathable, and I was able to adjust the pads using the spare set supplied to get the right fit. The helmet sits snug without moving, but at the same time, it doesn’t squeeze my face into hamster cheeks. I have been testing the MTB 4.0 helmet this autumn and winter, and I definitely did not find it too hot or sweaty.

I was lucky enough not to take a severe tumble while wearing this helmet, but I did feel entirely comfortable with the amount of protection it offers. It does not feel flimsy like it could snap on the first impact, but at the same time, it still feels fairly light. If I was entering an enduro race, I would consider taking a light a full-face like the DBX4.0.   

MTB 4.0 helmet features:

  • $239.99 MSRP (Available from Jenson USA and other retailers)
  • 22 vents
  • Removable mouth piece vent
  • Fidlock magnetic closure system
  • Dri-Lex® moisture-wicking, breathable, anti-odor, and washable inner liner
  • 360° Turbine Technology
  • Visor with breakaway function for rotational reduction in a crash
  • In-molded EPS + EPO impact foam
  • Weight: 850g (1.87 lbs) – size Medium tested
  • Certifications: AS/NZS 2063:2008, ASTM F1952–10, EN1078, CPSC 1203

The feature that stands out for me the most is the Fidlock magnetic closure system that allows me to minimize the faffing when putting on or removing the helmet, especially when wearing gloves. It is a simple thing, but it makes a big difference in comparison to traditional D-lock closure systems. The removable mouth piece at the front of the helmet was also a plus, as I could easily slot the bottle into my mouth through the gap without having to remove the helmet. Another excellent use for the removable mouthpiece cover could be helping with installing a chin-mounted action camera through the opening. 

The only thing that is really missing on this helmet is a tiltable visor. I wasn’t able to put my goggles on top of the helmet and instead had to take them off entirely. There hasn’t really been much in the way of the sun while I have been testing the MTB 4.0, but a tiltable visor would also really help with getting the right angle to block out some of the sun on exceptionally bright days. 

Overall, the Leatt MTB 4.0 helmet is an excellent all-rounder for those looking for a helmet for bike park days and enduro races. If you are looking for a lighter full-face, this should be on your short-list.

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