Fox Helmets

What's Going On Inside the Shell

The foundation of Fox's protection story is Varizorb EPS - a dual-density expanded polystyrene liner that uses two foam grades in the same shell. Harder outer foam disperses the initial energy of an impact; softer inner foam manages the slower, secondary crush. Think of it like a two-stage brake rather than locking the wheels. You get a more progressive response to impacts across a broader range of severities, which matters whether you've clipped a low branch or gone over the bars properly.

Layered on top of that is MIPS - the Multi-Directional Impact Protection System. Most real-world impacts arrive at an oblique angle, and MIPS addresses this with a low-friction slip plane between your head and the helmet. The liner can rotate a few millimetres independently of the outer shell during impact, reducing the rotational forces transmitted to the brain. It's standard fitment across most of Fox's current range, and at this point you'd be hard-pressed to justify a lid without it.

Ventilation across Fox's open-face helmets is deliberately generous, with deep channelled ports that move air efficiently even at the grinding pace of a humid summer climb. That matters in the UK more than the marketing often suggests - slow, steep woodland singletrack on a warm June morning will cook you in a poorly vented helmet long before you reach the descent that justifies wearing one.

The XT2 antimicrobial liner handles the sweat side of things. The padding wicks moisture away from your skin and the XT2 treatment actively works against the bacteria that turn your helmet into something you'd rather leave in the car. The liners are fully removable - more on that shortly.

Finding the Right Lid in the Fox Range

Fox's open-face helmets sit across three clear tiers, each aimed at a different type of rider.

• Mainframe: The entry point. Solid Varizorb EPS construction, good ventilation, available with or without MIPS. If you're newer to trail riding or want a reliable everyday lid without spending top dollar, this is the sensible starting point.
• Speedframe: Fox's premium half-shell trail helmet. Lower weight, more refined venting, and the full suite of tech including MIPS. The 360-degree fit system at the back lets you dial in retention with proper micro-adjustment rather than a clunky three-position ratchet. It sits snugly without creating hot spots.
• Dropframe: Extended coverage over the ears and the lower rear of the skull - closer to a full-face in terms of protection area, but without the chin bar. It's aimed squarely at aggressive enduro riding where you want more coverage than a standard half-shell offers, but prefer the breathability and communication of an open face. Worth considering if your riding involves committing descents on loose or technical ground.

Fox helmets are built around an intermediate oval head shape, which fits the majority of UK riders well. The 360-degree fit system - present on Speedframe and Dropframe - fine-tunes tension around the rear of your skull and is noticeably more precise than basic dial systems. Size up if you're between sizes; a lid that's slightly loose and properly adjusted will always outperform one that's marginally too tight.

For context, Bell helmets tend to run slightly rounder in the oval, while Giro helmets often suit a longer, narrower head shape. Fox sits comfortably in the middle, which is part of why the range works across such a broad spread of riders. 100% helmets are also worth a look if you're after an alternative with a strong goggle integration story.

Looking for DH-certified protection or youth sizing? Head over to our specific Fox Full Face Helmets or Fox Kids Helmets pages.

Goggle Compatibility and Keeping Your Lid Fresh

Fox open-face helmets are designed with goggle use in mind - not as an afterthought. The adjustable visor on models like the Speedframe and Dropframe has enough range to accommodate goggle strap thickness without the classic gap problem: that annoying strip of forehead exposed to grit and rain on a winter descent. The rear goggle retainer strap keeps your eyewear in place when the trail gets rough, which is worth more than it sounds when you're picking through technical root sections in low autumn light.

For UK winter riding specifically, seamless goggle compatibility is genuinely important. Muddy, wet descents in places like Glentress or the Quantocks throw up grit at speed, and a gap between visor and goggle turns a good run into a squinting mess. Fox's visor geometry handles this well across the range.

Matching your Fox lid with a good set of Fox gloves and a breathable Fox jersey makes practical sense - the fit systems are designed to work together and you won't find yourself fighting a collar against a chinstrap.

On the care side: the XT2 antimicrobial liner is removable and machine washable. Pull the padding out after a wet, gritty ride, pop it inside a mesh laundry bag, and run it on a gentle cold cycle. Air dry only - heat damages the foam backing. Do this every few rides rather than waiting until the smell forces the issue, and the liner will last considerably longer. The shell itself just needs a wipe with a damp cloth; avoid solvents, which degrade EPS over time. A fresh Fox jacket and clean kit for the next ride makes the whole thing feel more sorted.

One practical note: if you ride in all weathers - and in the UK, you do - check the visor screws periodically. Repeated removal and reattachment loosens them gradually, and a visor rattling at speed is an unnecessary distraction. A small dab of threadlock on reassembly sorts it permanently. Pair your helmet with Fox MTB shorts and you've got a coherent kit setup that works hard from car park to summit and back.