GMax · AT-21S
GMax AT-21S Anthracite
Quick Facts at a Glance
Verified Safety Snapshot
How this helmet’s verified certifications map to recognized safety homologations and crash testing.
Safety standards compliance is based on official manufacturer documentation and public safety laboratory test results. Always verify regional compliance labels on the physical helmet prior to use.
Verified Fit & Sizing Guide
Head shape profile matching and interactive size calculator based on verified manufacturer dimensions.
Designed for adventure riding with a slightly extended rear coverage; fits most head shapes but may feel tight on very large skulls due to the dual-sport shell design.
How to measure
Wrap a cloth measuring tape around your head just above your eyebrows and ears. Pull the tape comfortably snug, read the length, and repeat for consistency.
Design Concept & Background
"Built for Speed"
The Gmax GMax AT-21S is a benchmark Adventure / Dual Sport helmet crafted in Global Certified. Built around Advanced multi-composite aerodynamic shell geometry engineered for optimal impact absorption and stability, it is engineered specifically for Long Oval ergonomics. Designed for aggressive forward tuck and sport-touring postures, delivering maximum high-speed aerodynamic stability and full-coverage chin protection. Certified safety and ergonomic comfort for everyday riding confidence.
Key Highlights:
Rider Profile & Intended Use
Wo kaufen
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Preisverlauf & Trends
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Product Concept & Specifications
GMax (United States)Engineering & Biomechanical Safety Analysis
Features Advanced multi-composite aerodynamic shell geometry engineered for optimal impact absorption and stability paired with Anti-scratch Class-1 optical shield with Pinlock anti-fog lens compatibility and toolless quick-release. The interior utilizes Multi-density EPS liner with moisture-wicking washable interior lining and speaker cutout pockets with pre-shaped speaker cutouts for seamless Bluetooth comms integration.
The GMax AT-21S Anthracite is engineered as a high-integrity Adventure/Dual Sport protective system, utilizing a structural shell constructed from Polycarbonate. This structural layup is engineered to provide progressive kinetic energy dissipation during impact deceleration, distributing localized shock across outer lamina layers while minimizing deformation transfer into the internal multi-density EPS liner.
Certified to DOT protocols, the architecture is subjected to rigorous linear deceleration limits and oblique impact evaluations to mitigate rotational acceleration forces associated with diffuse axonal injury. For a deeper breakdown of rotational thresholds and impact testing speeds, consult our ECE 22.06 vs DOT vs SNELL engineering benchmark.
Internal geometry follows a Intermediate Oval cranial profile, designed to mitigate focal pressure hot spots across the parietal ridges while maintaining uniform radial clamping pressure along the zygomatic arch. Riders seeking optimal retention stability and break-in guidance should review the cranial aspect ratios and head shape guide as well as our 3D cheek pad density protocol.
Shell composite integrity and acoustic sealing are further optimized through channelized EPS porting and aerodynamic laminar profiling. To learn how shell composites resist stress cracking under prolonged environmental cycling, inspect the composite material comparative matrix.
Fit & Shell Structure
Intermediate Oval Shape
Balanced oval fit: standard ergonomic curvature fitting 80%+ of riders.
Safety & Certifications
Acoustics & Aerodynamics
Technology & Convenience
Interactive Size & Fit Finder
Designed for adventure riding with a slightly extended rear coverage; fits most head shapes but may feel tight on very large skulls due to the dual-sport shell design.
How to measure
Wrap a cloth measuring tape around your head just above your eyebrows and ears. Pull the tape comfortably snug, read the length, and repeat for consistency.
View on retailers
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Compatible Motorcycles for the GMax AT-21S Anthracite
Calibrated for upright windscreen deflection, all-terrain dust filtration, and long-travel suspension dynamics.
Data Confidence & Verification Provenance
Helmetsan enforces field-level verification and multi-source cross-referencing. Unverified values are explicitly flagged rather than estimated.