Leatt’s snap-together convertible MTB 4.0 Enduro helmet is one of only a couple of helmets with full DH certification that can still multitask as a lightweight open face trail lid once the chin guard is removed. And based on our testing, it’s one of the best full face or convertible helmets out there. 

It’s a versatile bit of kit that’s as light as many fixed enduro full-face lids, despite packing magnesium clasps to secure the chin guard and Leatt’s 360-degree Turbine Technology rotational impact protection system. There are also different polystyrene densities for superior energy absorption in a crash, with the dual-foam construction using EPS and EPO sectors to soak up the forces of both slow and high-speed strikes in different crash scenarios. 

The outer shell uses something called Polymer Compound, that’s a bit more flexible than typical fibreglass or carbon DH lids, and sculpted into a very low-profile shape considering this is a convertible lid. The whole exterior is wrapped, although some exposed EPS lies at the edges of the chinbar. We’ve used the previous generation a lot, and while it does scuff up, Leatt’s lid has proven very tough and survived a lot of knocks over time and we’ve not had any issues with the straps, the retention system or the chinbar mechanism.

Inside, the 360 turbines mentioned are embedded in the EPS in the form of squidgy wheels that twist if the helmet takes a glancing blow, so the shell can slide across the scalp. There aren’t pads everywhere inside like the Giro Insurgent helmet, but they are quite thick and well placed and the interior is pretty comfy without the soft turbines being noticeable. There’s zero irritating wobble or  rattle when riding either; so long as you cinch the rear retention dial reasonably tight. 

Even though your goggle strap covers up a few of the exhaust ports on the back, ventilation is excellent and almost a match for the Fox Proframe. Leatt’s lid never cooks your brain like a really padded full-face can, plus it’s much better at damping wind sounds and noise than most very open enduro full faces.

In open face mode, it does stick out marginally more than dedicated half shells, but you’d be hard pressed to notice the top half isn’t a ‘specific’ trail helmet as it’s as light, stable and comfy, which isn’t automatically the case with some of the wonky, top-heavy and hard-to-undo half shells that some convertible lids deliver. 

• Best mountain bike helmets: a bunch of brilliant brain savers
• Learn how to master the wheelie with Andy Barlow of Dirt School
• The 10 tools you should have in your workshop toolkit