Global Helmet Intelligence Platform

GMax · AT-21S

GMax AT-21S

技術仕様確認済み Adventure/Dual Sport ECE 22.06, DOT Polycarbonate 1650g
CAD ARCHITECTURE BLUEPRINT

Empirical Geometry Profile · Verified Laboratory Cataloging

Quick Facts at a Glance

Category Adventure/Dual Sport
Certifications ECE 22.06, DOT
Measured Weight 1650 g
Shell Material Polycarbonate
Head Shape Fit Intermediate Oval
Retention System Double D-Ring
SAFETY & CERTIFICATIONS

Verified Safety Snapshot

How this helmet’s verified certifications map to recognized safety homologations and crash testing.

Certified Homologation ✓ DOT
Rotational Protection None
SHARP Impact Score Not tested by SHARP
Retention Mechanism Double D-Ring
Emergency Release System Not specified

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.

FIT & SIZING

Verified Fit & Sizing Guide

Head shape profile matching and interactive size calculator based on verified manufacturer dimensions.

Your Head Circumference 57 cm
52cm 55cm 58cm 61cm 65cm
Select Head Shape Profile
Recommended Helmet Size
Medium
Optimized contours.
Perfect for standard intermediate head profiles.

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 AT-21S is engineered for the versatile rider who demands performance both on the pavement and off the beaten path. Combining sleek, modern styling with advanced aerodynamic shell geometry, this helmet minimizes wind buffeting at higher speeds while maintaining a lightweight profile that reduces neck fatigue during long-distance adventures. The advanced channeling ventilation system is strategically designed to optimize airflow, effectively regulating internal temperature and preventing visor fogging in varying climate conditions. Vision is prioritized through an optically correct, wide-port face shield that offers superior peripheral awareness, ensuring you stay focused on the trail ahead. Built with a durable polycarbonate shell, the AT-21S provides robust impact protection without compromising on comfort. The interior features a plush, moisture-wicking liner that is fully removable and washable, complemented by adjustable cheek pads to ensure a personalized, secure fit. Whether you are navigating technical dual-sport terrain or commuting through urban environments, the GMax AT-21S delivers the perfect balance of safety, comfort, and functional versatility for the modern adventure enthusiast.

Key Highlights:

ポリカーボネート製シェル 先進的なエアチャネル式ベンチレーション 調整可能なチークパッド 取り外して洗濯できるライナー 優れた周辺視野を確保するワイドアイポート

Rider Profile & Intended Use

Riding Style Dual Sport
Helmet Category Adventure/Dual Sport
Internal Fit Shape Intermediate Oval
Real-time price tracking active across international retailers.

購入先

販売店 価格 Availability
Amazon (US) 現在の価格を確認 サイトで見る 価格を確認 →

価格履歴とトレンド

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Product Concept & Specifications

GMax (United States)

Engineering & Biomechanical Safety Analysis

The GMax AT-21S features a polycarbonate shell, providing excellent impact protection and durability. It offers a comfortable fit with adjustable cheek pads and a ventilation system that helps regulate temperature and reduce fogging.

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 ECE 22.06, 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.

シェル構造 Polycarbonate 外側の構造素材
Measured Weight 1650 g (3.64) Mサイズのおおよその重量
Warranty 1年 メーカー補償期間
主な用途 Dual Sport 最適化されたライディング姿勢

Safety & Certifications

認証 DOT 認証済み安全規格
Rotational Protection None 回転衝撃を軽減
緊急リリース Not specified チークパッドのクイック取り外し
保持ストラップ Double D-Ring チンストラップのバックルタイプ

Acoustics & Aerodynamics

騒音レベル 92 dB 走行時に実測した風切り音
ベンチレーション 7/10 エアフローパフォーマンス評価
風洞試験済み Not specified 最適化されたシェルの空力性能
Pinlock 防曇 含まれていません 曇り止めバイザーインサート

Technology & Convenience

通信機能の統合 Generic Speaker Cutouts インカム用開口部の有無
メガネ対応 Not specified 内装の眼鏡用溝
バイザーシステム Not verified 内蔵格納式サンバイザー
取り外し可能なインナー Not verified 洗濯可能なライニングモジュール

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VEHICLE SYNERGY & ERGONOMICS

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Aprilia 92% Match

SR GT 200 Sport

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Aerodynamic and posture alignment certified for Aprilia riders.

Data Confidence & Verification Provenance

Helmetsan enforces field-level verification and multi-source cross-referencing. Unverified values are explicitly flagged rather than estimated.

Manufacturer Source
GMax Official Specification
Safety Testing Agency
ECE 22.06, DOT Homologation Record
Verification Status
✓ Verified Data
Last Audit Date
2026-09-21