What D3O Protection Actually Does
D3O shows up across a lot of Fox's knee and elbow guards, and it's worth understanding in plain terms rather than just as a name on a hangtag. It's a soft, flexible material under normal movement, so it doesn't feel like you're wearing rigid armour while you're pedalling or moving around. The moment it's hit with a sudden impact, like a fall, the material's molecules lock together almost instantly and it stiffens to absorb and spread the force. Once the impact's over, it goes soft again.
That's the general idea behind most modern body armour now, not just Fox's version of it: comfortable enough to forget you're wearing it, but ready to do its job the instant something goes wrong.
Getting Fox Helmet Sizing Right
Fox helmet sizing runs on its own scale rather than a universal small, medium, large, so it's worth checking the specific size chart for the model you're after rather than assuming your size in one Fox helmet carries across to another. Measure around the widest part of your head, roughly level with your eyebrows, and match that circumference against the chart.
Fit matters more with a helmet than almost anything else in this range. A helmet sitting slightly loose won't protect you properly no matter how good the foam and MIPS technology inside it are, so if you're between sizes or unsure, it's worth trying a couple on in store rather than guessing from an online chart alone.
How the Fox Mountain Bike Gear Works Together
Fox builds MIPS into most of its open face and full face helmets, using a slip layer inside the shell that helps redirect rotational force away from your brain during an angled impact rather than absorbing it head on. Pair that with D3O knee and elbow guards and you've got protection that covers both the impact itself and the twisting forces that come with most real-world falls, not just a straight on hit.
Underneath the more visible armour, a lot of Fox's protective gear also uses low-profile mesh padding at pressure points like the hips and tailbone. It's there to take the edge off a hard landing without adding bulk or trapping heat the way thicker padding would.
Fabric Tech for Every Melbourne Trail Day
Fox mountain bike gear is partnered with a few established textile makers rather than developing everything in-house (such as Cordura and Polartec), and it shows in the range. Fox's inhouse TruDri fabric handles moisture wicking in jerseys and base layers, pulling sweat away from your skin on a hot climb. Cordura shows up in high wear areas where abrasion resistance matters more than breathability, and Polartec lines some of the cooler weather gear for genuine warmth without excessive bulk.
For Melbourne's mix of conditions, it's worth building toward a couple of options rather than one do it all jacket. Lightweight mesh gear covers the hot months, while a seam sealed, DWR coated rain jacket earns its keep on the wetter, colder rides through winter.
Caring for Your Fox Mountain Bike Gear
Fox's technical fabrics and armour hold up a lot longer with the right care. Wash on a cold cycle using a mild detergent, and avoid fabric softener, which coats the fibres and reduces breathability over time. Heat drying, softeners and bleach are a hard no across the whole range, helmets, gloves and riding pants included, since they all shorten the life of the materials in different ways.
Get Trail Ready With Ivanhoe Cycles
If it's the helmets you're after specifically, our Fox MTB helmets range covers the full lineup in more depth. Pair your Fox kit with a proper set of MTB gloves and a pair of MTB shorts, and if you're still shopping for the bike itself, our mountain bikes range is worth a look too.