Arai Quantum-X Steel Helmet
Features Round oval shape, achieved by using an interior head liner that combines thicker front and rear pads with thinner side pads, is designed for riders whos heads are slightly... Read More
Features
- Round oval shape, achieved by using an interior head liner that combines thicker front and rear pads with thinner side pads, is designed for riders whos heads are slightly wider rather than elongated
- Improved Glance Off Ability — Variable Axis System (VAS) shield system lowers the pivot point by an average of 24 mm, making the shell surface area in the critical temple area much smoother and better able to reduce impact energy getting into the helmet
- Improved Shield Latch — The VAS latch captures and securely holds the shield closed to help prevent unexpected opening
- In addition to the de-mist function, the larger latch allows for intuitive and seamless shield operation
- QVF & QVR Intake/Exhaust Ducts — Features QVF three-position intake and QVR exhaust ducts for excellent air intake and exhaust performance when riding
- Side vent still serves as an exhaust vent even when the front shutter is closed on the top duct
- FCS® Cheek Pads — The contoured shape—combined with multiple layers of varying foam densities supported by a foam “spring”—cradles the face and makes on-off easier while helping to block even more wind noise
- Water repellent ES Chin cover comes installed, enhancing the Egg Shape of the helmet
- Chin cover smooths airflow, increases exhaust from the mouth area and reduces wind noise coming up from below
- The Peripherally Belted - Super Complex Laminate Construction (PB-SCLC) shell design combines multiple materials and techniques that deliver both performance and affordability
- Comes with VAS-Max Vision (VAS-MV) shield that accepts the VAS-MV Pinlock® lens
- Pinlock® 120 MaxVision™ included
How to measure
Measure the circumference of your head in cm across the forehead, above the eyes and ears and over the small bump at the back of the head — read the size where the tape joins. Focus on head size (crown fit) first, then fine-tune with cheek pads. Arai stresses the chart is a STARTING POINT: the best fit comes from trying on Arai's different interior fit shapes.
Arai Helmets size chart
| Size | Head circumference (cm) | Head circumference (inches) |
|---|---|---|
| XS | 53-54 | 20 7/8 - 21 1/4 |
| S | 55-56 | 21 5/8 - 22 |
| M | 57-58 | 22 1/2 - 22 7/8 |
| L | 59-60 | 23 1/4 - 23 5/8 |
| XL | 61-62 | 24 - 24 3/8 |
| 2XL | 63-64 | 24 3/4 - 25 1/4 |
| 3XL | 65-66 | 25 5/8 - 26 |
One head-circumference chart covers all current Arai models — what differs per model is interior SHAPE, not size: Intermediate Oval (Corsair-X, Contour-X, Defiant-X, Regent-X, XD-4/XD-5, VX-Pro4 — fits most North American heads), Round Oval (Quantum-X), Long Oval (Signet-X). Try the shape that matches your head. Not every model runs every size (e.g. Corsair-X standard range XS–2XL). Arai publishes CM ONLY on every official arm — inch values here are exact conversions (×2.54, nearest 1/8″), not manufacturer-printed; retailer inch charts differ because they round differently. Labels normalized (XXL/XXXL → 2XL/3XL). Extreme sizes (3XS 49-50, 2XS 51-52) are select-model/special-order and not on the current chart. No youth motorcycle chart exists (the CK-6 is a karting helmet). Verified from araiamericas.com chart image + whyarai.co.uk 2026-07-13.
Manufacturer sizing data · verified July 13, 2026