Bell 4Forty Air MIPS Mountain Bike Helmet | Trail & All-Mountain MTB

The Bell 4Forty Air MIPS is a dedicated mountain bike helmet built for trail and all-mountain riders who want maximum protection and airflow without moving into a full-face lid. It occupies the sweet spot in the half-shell MTB category — offering extended rear head coverage typical of trail-focused designs, aggressive ventilation that keeps pace with high-output riding, and MIPS rotational protection as standard.

MIPS is non-negotiable in a modern MTB helmet. The forces involved in trail riding — particularly the oblique impacts common in off-camber crashes and technical terrain tumbles — make rotational protection genuinely important. Bell's MIPS integration in the 4Forty Air is seamlessly built into the fit system, so it doesn't complicate sizing or create any perceptible movement during normal riding.

The "Air" designation reflects a real ventilation upgrade over the standard 4Forty. Larger vent openings and a revised internal channelling system deliver noticeably more airflow on climbs and sustained technical efforts, making it a better choice for riders who run hot on physical trails. The Float Fit dial system provides quick micro-adjustments and holds firm on rough terrain where cheaper retention systems tend to shift and loosen.

Available in White and Matte Black — two clean colourways that work with most kit and bike setups. Sizes Small/Medium and Large/Extra-Large cover the majority of adult head sizes. Whether you ride flow trails, enduro-style terrain, or aggressive singletrack, the 4Forty Air MIPS offers a strong combination of protection, breathability and value.

Free shipping Australia-wide on orders over $100. In stock now at Oz Backcountry.