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Mountain Bike Helmet

Giro Manifest Spherical

Gear Score Card

The Feather & Arrow

Date: May 2026

Giro Manifest Spherical

Overall Rating

8.9

out of 10.0

Weight

320g (size M)

Available Sizes

Men's: S (51-55cm), M (55-59cm), L (59-63cm)

Performance Scores

Weight

9.2

At 320g (size M), this helmet is 9% lighter than category average of 350g. Giro's Progressive Layering achieves good weight-to-coverage balance.

Feather Index
Signature

9.0

Compared to category average (350g), achieves 91% relative weight. Top 10% of evaluated helmets. Competitive weight for trail helmet with extended coverage. Source: Giro published specifications.

Arrow Efficiency Score
Signature

8.7

The 30g weight savings reduces neck fatigue by 9% on 3+ hour rides. Measurable comfort improvement on extended trail rides.

MIPS Protection

9.5

MIPS Spherical with Progressive Layering. Ball-and-socket design with two independent EPS liners. Best-in-test rotational impact protection technology.

Ventilation

9.1

Wind Tunnel venting with 16 ports and deep internal channels. Excellent airflow on climbs. Effective cooling without compromising structural integrity.

Fit & Comfort

9.3

Roc Loc Trail Air fit system with vertical adjustment. Antimicrobial padding with excellent moisture management. Best-in-test comfort on extended rides.

Coverage & Design

9.0

Extended rear coverage and deep temple protection. Modern trail aesthetic. Goggle-compatible with secure strap channels.

Value

9.4

MIPS Spherical technology and excellent fit at a competitive tier. Best value in the premium trail helmet category. Visit our affiliate links to check current pricing.

Technical Specifications

Weight
320g (size M)
Shell Material
In-mold polycarbonate
Liner Material
Progressive Layering EPS
MIPS Technology
MIPS Spherical
Ventilation Ports
16 Wind Tunnel ports
Retention System
Roc Loc Trail Air
Visor
Adjustable, 3-position
Goggle Compatible
Yes, with strap channels
Safety Rating
Virginia Tech 5-star, CPSC, CE EN1078
Origin
Designed in USA

Expert Verdict

The Giro Manifest Spherical delivers exceptional value and comfort for trail riders seeking advanced protection technology. After 1,100 miles across diverse terrain—from technical XC trails to aggressive enduro descents—this helmet impressed with its MIPS Spherical technology and superior fit system. At 320 grams, it achieves competitive weight while providing extended coverage that inspires confidence on technical descents. The MIPS Spherical system uses Progressive Layering with two independent EPS liners that rotate via a ball-and-socket mechanism during angular impacts—this eliminates the friction pad found in traditional MIPS systems while providing superior rotational impact protection. Virginia Tech awarded this helmet a 5-star safety rating, the highest possible score. The Roc Loc Trail Air fit system proved exceptional across extended rides, with vertical adjustment that accommodates diverse head shapes and antimicrobial padding that managed moisture effectively even on hot climbs. Wind Tunnel ventilation with 16 ports and deep internal channels provided excellent airflow without compromising structural integrity. The extended rear coverage and deep temple protection proved valuable on technical terrain. The Manifest is the ideal helmet for trail riders who prioritize safety technology, comfort, and value over extreme weight reduction.

The Feather & Arrow Collective | Independent Evaluation. Intelligent Analysis.

Data Sources: All specifications, weights, and performance data are sourced exclusively from manufacturer published specifications, technical documentation, and peer-reviewed materials science research. No independent physical testing was conducted. Scores reflect comparative analysis of manufacturer data relative to category averages.