The HJC C91 Solid Modular Helmet is designed for street and touring riders who want the convenience of a flip-up chin bar with the protection and comfort of a full-coverage motorcycle helmet. Its lightweight polycarbonate composite shell, integrated sun shield, moisture-wicking interior, and HJC ventilation system make it a versatile choice for commuting, touring, and everyday riding.

• Modular flip-up helmet design
• Advanced polycarbonate composite shell provides lightweight protection and comfort
• CAD-developed shell design helps provide a secure and comfortable fit
• Advanced Channeling Ventilation System promotes front-to-back airflow
• Multiple intake and exhaust vents help remove heat and humidity
• HJ-17 Pinlock®-ready clear face shield
• RapidFire™ shield replacement system allows quick, tool-free shield removal and installation
• Integrated internal sun shield
• Moisture-wicking interior helps improve rider comfort
• Removable and washable crown liner and cheek pads
• Glasses-friendly interior design
• Speaker pockets accommodate Bluetooth communication systems
• Micrometric chin-strap closure
• Designed for street, commuting, and touring motorcycle riding

HJC C91 Adult Helmet Size Chart

How to Measure: Wrap a soft measuring tape around the widest part of the head, just above the eyebrows and ears. Keep the tape level and comfortably snug, repeat the measurement, and use the largest result.

Fit Note: A motorcycle helmet should fit securely and evenly around the head without painful pressure points. It should not shift excessively when the rider turns or shakes their head.

The interactive size finder uses head circumference in inches. For helmets, proper secure fit should take priority over a looser fit preference.