GMax · AT-21S
GMax AT-21S
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.
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"
GMax AT-21S 专为追求在铺装路面和越野路段均有出色表现的多功能骑手而设计。该头盔将时尚现代的设计与先进的空气动力学外壳几何结构相结合,在高速行驶时最大限度地减少风力干扰,同时保持轻量化轮廓,减少长途探险中的颈部疲劳。先进的通道式通风系统经过战略性设计,旨在优化气流,有效调节内部温度并防止在不同气候条件下 visor 产生雾气。通过光学正确的宽视野面罩,优先保证视野,提供卓越的周边感知,确保您专注于前方的路径。AT-21S 由耐用的聚碳酸酯外壳制成,在不牺牲舒适性的前提下提供强有力的冲击保护。内衬采用柔软的吸湿材料,可完全拆卸并清洗,并配备可调节的颊垫,确保个性化的稳固贴合。无论您是在应对技术性双用途地形,还是在城市环境中通勤,GMax AT-21S 都能为现代探险爱好者提供安全、舒适和功能多样性的完美平衡。
GMax AT-21S represents an empirical engineering balance between aerodynamic stability and high-absorption cranial protection. Developed under GMax's strict quality assurance standards in United States, the shell profile is precision-molded to minimize high-velocity turbulent drag while maintaining comprehensive multi-axis impact attenuation.
Within the Adventure/Dual Sport segment, ergonomic weight distribution and acoustic insulation are paramount. The chassis geometry is tailored to distribute mass directly above the cervical pivot axis, counteracting high-speed buffeting and minimizing long-distance rider fatigue. Inspect the verified laboratory telemetry and structural analysis below for detailed performance parameters.
Key Highlights:
Rider Profile & Intended Use
去哪里购买
| 零售商 | 价格 | Availability | |
|---|---|---|---|
| Amazon (US) | 查看实时价格 | 在网站上查看 | 查看价格 → |
价格历史与趋势
ℹ️ Helmetsan 是一个独立的摩托车安全与决策引擎。当您查看价格或通过零售商链接购买时,Helmetsan 可能会获得联盟佣金,且不会向您收取额外费用。
Product Concept & Specifications
GMax (United States)Engineering & Biomechanical Safety Analysis
GMax AT-21S 采用聚碳酸酯外壳,提供卓越的冲击保护和耐用性。它配备可调节颊垫,提供舒适的贴合感,并拥有有助于调节温度和减少雾气的通风系统。
The GMax AT-21S 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, ECE 22.06 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
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.
Part numbers
| Product style | MFR. product # | SKU | Availability |
|---|---|---|---|
| Gloss Black / | — |
GMA-AT21-BLK | instock |
| Anthracite / | — |
GMA-AT21-GRE | instock |
| Hi-Viz Yellow / | — |
GMA-AT21-YEL | instock |
| Urban TC-1 / | — |
GMA-AT21-URB | instock |
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Compatible Motorcycles for the GMax AT-21S
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.