GIRO Giro Ratio Mips Helmet — Open-face, Hard Shell, In Form Fit, Stack Vent, Matte Black

The GIRO Giro Ratio Mips Helmet is an open-face, hard-shell cycling helmet engineered for urban and recreational riders seeking lightweight protection and adjustable comfort. It combines a durable two-piece hard shell with MIPS rotational protection and an In Form fit system to provide a secure, customizable fit. Stack Vent ventilation and Thermostat Control adjustable venting help manage airflow, while a matte black finish delivers a subdued, versatile look.

Advantages

The hard shell with an in-mold lower wrap offers a balance of durability and reduced weight compared with heavier multi-piece constructions. Integrated MIPS is designed to help redirect rotational forces in certain impacts. The In Form fit system provides quick, tool-free adjustment for a stable fit, and Thermostat Control allows on-the-fly airflow tuning. Stack Vent alignment improves goggle ventilation and reduces fogging when goggles are used.

Suitable for

• Urban commuting and e‑bike riding
• Recreational road and mixed-surface cycling
• Riders who want adjustable ventilation and fit
• Use with compatible goggles or aftermarket audio accessories

When it may not be suitable

This open-face hard-shell helmet is designed primarily for urban and recreational cycling; it does not provide the same facial or full-face protection required for high-risk disciplines such as downhill mountain biking or motorized sports. Riders who need certified full-face coverage or specific competition certifications should consider helmets designed for those activities.

Key specifications

• Shell construction: two-piece hard shell with polycarbonate lower wrap bonded to the liner
• Protection technology: Integrated MIPS (rotational impact protection)
• Fit system: In Form adjustable dial with up to 6 cm of adjustment
• Ventilation: Stack Vent alignment and Thermostat Control adjustable venting
• Style: open-face design, matte black finish
• Compatibility: designed for seamless use with Giro goggles and compatible with certain aftermarket audio systems

How to use

Place the helmet on the head so it sits level and covers the forehead without tilting back. Use the In Form fit dial at the base to tighten or loosen the fit until the helmet feels secure and stable. Adjust the chin strap so it is snug under the chin and allows one or two fingers of space. Use the Thermostat Control to open or close vents for desired airflow while riding. When wearing goggles, align them with the helmet’s Stack Vent to help maintain clear vision.

What to consider before purchase

• Head size and correct sizing — ensure the selected size corresponds to your head circumference
• Intended use — verify this open-face helmet meets your activity’s protection needs
• Ventilation preferences — Thermostat Control and Stack Vent offer adjustable airflow
• Accessory compatibility — check fit with your goggles or any aftermarket audio systems

Usage recommendations

Regularly inspect the helmet for visible damage after any impact and replace it if compromised. Follow manufacturer guidance for cleaning and storage to maintain performance of the hard shell, fit system and MIPS components.