Global Helmet Intelligence Platform

Alpinestars · SM5

SM5 Racer TC-2

技术规格已验证 Dirt/MX DOT, ECE 22.05 Polymer 1453g
CAD ARCHITECTURE BLUEPRINT

Empirical Geometry Profile · Verified Laboratory Cataloging

Quick Facts at a Glance

Category Dirt/MX
Certifications DOT, ECE 22.05
Measured Weight 1453 g
Shell Material Polymer
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, ECE 22.05
Rotational Protection None
SHARP Impact Score 4/5 Stars (SHARP UK)
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.

The Alpinestars SM5 Racer TC-2 is a motocross/dirt bike helmet designed for off-road racing. It features a carbon fiber composite shell with an EPS liner and a removable chin bar (TC-2). The fit is generally aggressive and low-profile, suitable for riders with Intermediate Oval head shapes who prefer a tight, secure fit typical of MX helmets.

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

"Ride Safe"

Built for aggressive dirt performance, the Alpinestars SM5 Racer TC-2 is crafted for intense dirt riding with ultra-wide goggle eyeport stabilization across punishing tracks and trails. Its High-Yield Impact-Resistant Polycarbonate / Lexan shell tips the scales at 1453g, channeling boundary-layer airflow to maintain a ~99 dB acoustic cabin profile while meeting DOT, ECE 22.05 impact standards. An ultra-breathable, antimicrobial interior liner stabilizes the helmet during aggressive terrain vibration, locked in securely with track-proven Double D-Ring retention.

Key Highlights:

MIPS 冲击防护系统 高强度聚合物外壳 中等椭圆头型 先进通风系统 紧急释放侧垫 多密度 EPS 内衬 可拆卸清洗内衬

Rider Profile & Intended Use

Helmet Category Dirt/MX
Internal Fit Shape Intermediate Oval
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Product Concept & Specifications

Alpinestars (Italy)

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 SM5 Racer TC-2 is engineered as a high-integrity Dirt/MX protective system, utilizing a structural shell constructed from Polymer. 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 22.05 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.

外壳结构 Polymer 外部结构材料
Measured Weight 1453 g (3.2) 中号尺寸的大约重量
Warranty 2 Years 制造商保障期限
主要用途 Not specified 优化的骑行姿态

Safety & Certifications

认证 DOT, ECE 22.05 经认证的安全标准
Rotational Protection None 减轻旋转冲击
紧急释放 Not specified 脸颊垫快速拆卸
固定带 Double D-Ring 下巴带扣类型
SHARP 碰撞评级 4/5 SHARP UK 冲击测试成绩已验证

Acoustics & Aerodynamics

噪音水平 99 dB 实测高速风噪
通风 7/10 气流性能评级
风洞测试 Not specified 优化的外壳空气动力学
Pinlock 防雾 未包含 防雾镜片内衬

Technology & Convenience

通信设备集成 Generic Speaker Cutouts 对讲机开孔可用性
适合佩戴眼镜 Not specified 内衬眼镜凹槽
面罩系统 Not verified 一体式下拉式遮阳镜
可拆卸内衬 Not verified 可清洗内衬模块

Regional Legality & Compliance

🇺🇸 US Legal For Off-road Use
Required: DOT

Certified for use in the United States; meets DOT FMVSS 218 standards.

🇪🇺 EU Legal For Off-road Use
Required: ECE 22.05

Compliant with ECE 22.05 regulations for use in European markets.

🌐 CA Legal For Off-road Use
Required: DOT

Accepted for use in Canada under DOT standards.

Regional Legality Guidance

US

Status: Legal for Off-Road Use

Required: DOT

Certified for use in the United States; meets DOT FMVSS 218 standards.

EU

Status: Legal for Off-Road Use

Required: ECE 22.05

Compliant with ECE 22.05 regulations for use in European markets.

CA

Status: Legal for Off-Road Use

Required: DOT

Accepted for use in Canada under DOT standards.

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Data Confidence & Verification Provenance

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

Manufacturer Source
Alpinestars Official Specification
Safety Testing Agency
DOT, ECE 22.05 Homologation Record
Verification Status
✓ Verified Data
Last Audit Date
2026-09-20