Sidi Rex Air Motorcycle Boots White/Red 391

Long days in the saddle — or long laps on track — demand a boot that fits like it was made for you and keeps you cool when the temperature climbs. The Sidi Rex Air in White/Red 391 delivers exactly that: a perforated microfibre upper paired with a precision Dual-Dial closure system that locks your foot in place without a single pressure point, so comfort never becomes the thing you are fighting against.

Key Features

• Perforated microfibre upper with integrated Air Ventilation System positioned for maximum airflow during dynamic riding
• Dual-Dial closure on both sides for independent, millimetre-precise fit adjustment regardless of calf width
• High-grade TPU impact protectors and fibreglass-reinforced exoskeleton structure for race-derived rigidity
• Replaceable shin plate and sliders so worn components can be swapped rather than the whole boot replaced
• Asymmetric heel cup and Side-Slip design for a secure, confident contact point against the motorcycle
• Intelligently engineered flex zones that allow natural movement when shifting and braking without compromising lateral support

All-Day Comfort Through Smarter Fit

The Rex Air's Dual-Dial fastening system is the feature that sets it apart for riders who cover real distance. Each dial operates independently, letting you fine-tune the fit across the instep and upper calf separately. The result is even pressure distribution, no localised hot spots and a boot you can wear for hours without wanting to pull over. Whether you have a narrow ankle or a more muscular leg, the system accommodates you precisely — fast to fasten, easy to release.

Airflow Where It Counts

The perforated upper is not a styling detail — it is a functional decision. Air circulates continuously through the microfibre panels, reducing heat build-up and wicking moisture away from the foot. The Air Ventilation System channels are positioned specifically where the boot sees the most heat during sport riding: across the toe box and along the sides of the shaft. The outcome is cooler feet, lower fatigue and better concentration on longer summer rides or consecutive track sessions.

Racing-Grade Protection

Sidi engineered the Rex Air's protective architecture from competition experience. The fibreglass-reinforced exoskeleton wraps the boot's critical zones with structural rigidity that absorbs and distributes impact energy before it reaches the rider's foot. TPU impact protectors cover the ankle and heel, the asymmetric heel cup adds lateral control in cornering, and the Side-Slip design maintains a predictable contact surface against the footpeg. Both the shin plate and the sliders are replaceable, extending the usable life of the boot considerably beyond what a non-serviceable alternative could offer.

Control on Road and Track

The high-abrasion-resistant upper handles the contact wear from footpegs and levers without deteriorating prematurely. The carefully mapped flex zones allow the natural dorsiflexion needed for smooth brake and gear inputs while maintaining the torsional stiffness that prevents the foot from rolling in a slide. The White/Red 391 colourway is designed to be legible in race conditions and complements a wide range of white or red-accented sportsbike liveries.

Sidi and Sustainability

Sidi actively supports the UN Sustainable Development Goals and is committed to a continuous reduction of its CO₂ emissions, working towards responsible manufacturing practices with a long-term perspective.

Fitment & Compatibility

The Sidi Rex Air White/Red 391 is a sport and track motorcycle boot suitable for road and circuit use. Available in whole sizes 39 through 48 to accommodate the full range of adult riders. No vehicle-specific fitment restrictions apply — these are rider footwear.

Specifications

• Brand: Sidi
• Model: Rex Air
• Colour: White/Red
• Model number: 391
• Upper material: perforated microfibre
• Closure system: Dual-Dial (independent adjustment each side)
• Protection: TPU impact protectors, fibreglass-reinforced exoskeleton, asymmetric heel cup
• Replaceable components: shin plate, sliders
• Ventilation: Air Ventilation System integrated into upper
• Sizes available: 39–48