HJC · C91 · Modular
The HJC C91 Nepos is a modular motorcycle helmet built for everyday riding with the convenience of a flip-up design. It uses an Advanced polycarbonate composite shell and was developed with advanced CAD technology to focus on fit and comfort, while keeping weight in check at 3.76 lbs / 1706 grams (approx, based on Size Medium).
For changing light and weather, the C91 Nepos combines a Pinlock®-ready HJ-17 visor with an integrated internal sun shield that moves forward and back with a manual control. Venting is managed by a large top vent feeding deep EPS channels, helping move air through the helmet during the ride.
The C91’s chin bar is designed around a single-lever operation that’s easy to use, including with gloves on. That modular functionality helps riders adapt quickly at stops without giving up the full-face configuration when it’s time to roll again.
Up front, the C91 uses a Pinlock®-ready HJ-17 visor paired with an integrated internal sun shield. The sun shield uses a manual mechanism that allows simple forward-and-back movement, making it easier to manage glare as conditions change during daily rides.
Inside, the C91 features a SuperCool® interior with a top liner and cheek pads made with moisture-wicking, antibacterial fabric to support cooling comfort. The crown and cheek pads are removable and washable, helping riders keep the fit feeling fresh over time.
Ventilation
HJC’s Advanced Channeling Ventilation System (ACS) is designed to keep air moving through the C91 during the ride. It draws in cooler air through front intakes, routes it through the helmet’s internal airflow channels, and then releases warmer air through rear exhaust vents. The C91 also uses a large top vent and deep EPS channels to help distribute airflow, aiming to reduce heat buildup for a more comfortable ride in a range of conditions.
Communication
The C91 is Smart HJC ready for use with the 10B or 20B Bluetooth systems (sold separately). This setup is intended to make it easier to add communication features such as GPS navigation and music capability when a compatible unit is installed, keeping controls integrated for a cleaner helmet setup.
Shield
The C91 includes HJC’s RapidFire™ shield replacement system to simplify swapping the visor when needed. It’s designed to make removal and installation straightforward, supporting riders who like to change a shield for cleaning, replacement, or different conditions while continuing to use the HJ-17 visor platform.
| Certifications | DOT |
|---|---|
| Weight | 3.76 lbs / 1706 grams (approx, based on Size Medium) |
C91 Helmet Manual (PDF) HJC Helmet Size Chart
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