Smith Mainline MIPS Full-Face Helmet Review
A top-tier full-face helmet that balances high-end protection, ventilation, and comfort—ideal for enduro, downhill, and e-bike riders who demand both safety and performance.
Product Overview
Smith Mainline MIPS Full-Face Helmet
Price: ~$300–$350
Manufacturer: Smith Optics
Target Riders: Mountain bikers, downhill riders, e-skate or e-bike users
Build & Materials: In-mold polycarbonate shell, Koroyd impact structure, EPS foam, MIPS liner
Certifications / Safety Claims: ASTM F1952 (downhill), CPSC, CE EN 1078, NTA 8776 (e-bike)
Our Verdict
The Smith Mainline MIPS is a standout full-face helmet that does many things right. It delivers strong protection, excellent ventilation, and a comfortable, lightweight ride. The ability to fine-tune the fit via multiple cheek pads and liners is a major plus. That said, its MIPS liner can produce noticeable noise, which some riders find irritating when not in motion. If you’re looking for a high-end full-face helmet for mixed use (pedal + downhill) with top certifications, this one deserves serious consideration.
Reasons to Buy
- Fully downhill-certified (ASTM F1952) plus other major safety standards
- Koroyd construction + MIPS for multi-layer impact protection
- 21 fixed ventilation vents for airflow
- Several interchangeable liners and cheek pads to dial in fit
- Lightweight for its category
- Good integration with goggles
Reasons to Avoid
- MIPS liner can squeak or rub inside the helmet
- No rear fit dial—fit adjustment relies solely on pads
- Less ideal for very hot climates due to full-face coverage
- Premium price
Test Results & Ratings
| Feature | Rating (0–10) | Notes |
|---|---|---|
| Ride Comfort | 9.0 | Plush liners, good helmet balance, minimal pressure points |
| Ventilation | 8.5 | Excellent airflow via 21 vents and Koroyd channels |
| Safety / Certification | 9.5 | Downhill, e-bike, and bicycle standards met |
| Weight & Fit | 8.5 | Well-balanced, though heavier than half-shell lids |
| Beginner Friendly | 8.0 | Simple to use, but noise might bother some users |
Ride Comfort
Smith equipped the Mainline with quality, moisture-wicking liners and multiple thickness options for cheek pads and neck rolls. Once dialed in, the helmet feels secure without pressure points. For many riders, it transitions from pedal climbs to downhill sections without fatigue.
Ventilation
This helmet shines in ventilation. With 21 vents and internal air channels built through the Koroyd structure, air moves freely from front to back, keeping you cool on climbs and fast descents. The chin bar vents also help with breathing and cooling during aggressive riding.
Safety & Certification
The Smith Mainline meets a collection of top-tier standards: ASTM F1952 for downhill, CPSC and CE EN 1078 for general bicycle use, and NTA 8776 for e-bike safety. Its combination of a hard shell, EPS foam, Koroyd energy-dissipating structure, and MIPS liner offers strong protection against both linear and rotational impacts.
Weight & Fit
In its size medium, the Mainline weighs in around 770 grams (27 ounces). That’s impressive for a full-face with all its features. Fit adjustment is handled via pads and interchangeable liners rather than a rear dial. For many users, this works fine, though having to trust pad options instead of micro-adjust may be a disadvantage for some.
Beginner Friendly
While the Mainline is designed for serious riders, it’s also approachable for less experienced users who want a high-performance full face. The multiple pad options simplify achieving a snug fit. However, the potential sound from the MIPS liner could distract some riders at low speed.
Common Issues & Notes
- Squeaking / noise: Many users report a rubbing or squeaking noise from the MIPS liner when turning the head while stationary. Some reduce it by inserting small buffer materials between the liner and shell.
- No fit dial: Since it lacks a rear adjuster, correct pad selection early is important to avoid a loose or tight fit.
- Price: As a premium helmet, the cost is high, so expect to commit to proper care and usage to justify it.
Should You Buy the Smith Mainline MIPS Helmet?
Yes—if you’re looking for a full-face helmet that handles climbs, descents, and e-bike rides, all in one package. The safety credentials, ventilation, and comfort make it a versatile, premium pick. Just be aware of the MIPS liner noise and ensure you get the right fit from the start.
