Smith Hardline Composite vs Smith Mainline MIPS: Full-Face Helmet Comparison
When it comes to full-face mountain bike helmets, Smith Optics offers two high-end options for aggressive trail riding: the Hardline Composite and the Mainline MIPS. Both helmets use advanced safety technology (Koroyd® impact-absorbing material and Mips® rotational protection) and are aimed at riders seeking extra confidence on steep or technical terrain. The Mainline is a “pedal-friendly” enduro helmet that is relatively light and well-ventilated, while the Hardline is a beefed-up, downhill-focused lid. We’ll compare their specs, features, comfort and ventilation, as well as ideal use cases, to help riders choose the right helmet for their style.
| Feature | Smith Hardline Composite | Smith Mainline MIPS |
|---|---|---|
| Shell Material | Composite (fiberglass/carbon) | Polycarbonate |
| Safety Tech | Complete KOROYD® inner honeycomb + Mips® Safety System | Complete KOROYD® coverage + Mips® Brain Protection System |
| Weight (Size M) | 990 g (35 oz) | 770 g (27 oz) |
| Ventilation | 16 vents, AirEvac™ system integrates with goggles | 21 vents, AirEvac™ system for fog-free goggle use |
| Fit / Padding | 2 crown liners, 2 neck rolls, 2 cheek pads (all washable). Cheek pads are quick-release for emergencies. | 2 crown liners, 2 neck rolls, 3 cheek pad thickness options (washable). Standard removable pads. |
| Visor | Adjustable break-away visor for camera mount | Adjustable visor (non-breakaway) |
| Strap | D-ring chin strap | D-ring chin strap |
| Certifications | CPSC, EN1078, AS/NZS 2063, ASTM F1952 (Downhill certified) | CPSC, EN1078, NTA-8776 (e-bike), ASTM F1952 (Downhill) |
| Collarbone Protection | Collarbone impact protection zone disperses force on impact during a crash to aid in reducing collarbone injuries from the edge of a helmet | None |
| Use Case | Pure downhill focus – more coverage & padding; ideal for bike parks or fast DH lines | Enduro and trail – lighter for climbing, but still DH-certified for descent |
Both helmets integrate with Smith’s AirEvac™ ventilation channels for use with goggles, helping to funnel heat out the back of the helmet. In practice, however, the two models feel quite different on the head.
Smith describes the Mainline as a “breathable, lightweight helmet” built for going “big and fast” in enduro or downhill. At only ~770 g, it is one of Smith’s lightest full-face helmets. The generous venting (21 fixed vents) and open internal air channels make the Mainline feel airy for a full-face. Reviewers note it is very comfortable even on all-day rides; one tester could climb comfortably in the 60–70°F range without overheating. The Mainline’s shell is hard polycarbonate with Koroyd and EPS foam inside, giving it the same Downhill (ASTM F1952) certification as pure DH lids. It comes with extra padding kits (3 cheek-pad thicknesses plus multiple liners and neck rolls) so you can fine-tune the fit.
In contrast, the Hardline Composite is built more like a race-ready downhill helmet. It has a composite shell (fiberglass/carbon) and adds an engineered collarbone impact zone at the bottom edge to protect the rider’s shoulders. Its Koroyd+EPS interior is thicker, and the cheek pads use Smith’s quick-release system to allow rescuers to remove the helmet easily in an emergency. The Hardline is notably heavier at about 990 g (over 2 lbs 3 oz) and has fewer vents (16 vents), so it doesn’t feel as “airy” as the Mainline. One tester summarized it well: “It breathes well enough for a downhill-focused full-face… but it’s nowhere near as light and airy as the Mainline, and that’s sort of the point. Instead my head feels more locked in and protected.” The breakaway visor is stronger for impact and adjustable high for cameras, unlike the standard visor on the Mainline.
In terms of comfort and fit, both helmets are very well-padded. The Mainline’s interior is praised for being plush – reviewers felt it was extremely comfortable on long rides. It has less shell contact on the sides of the head than some other full-face models, and its multiple pad options let you get a snug but comfortable fit even during long enduro stages. The Hardline also fits the face well but is slightly more constricting around the cheeks; Smith uses size-specific shells (S/M/L) and also provides multiple pads to tune the fit. Be aware that the Hardline uses a traditional D-ring strap and a flush chin strap design, which some riders find harder to operate with gloves.
Ventilation: In real-world use, the Mainline’s 21 vents (including large chin-bar intakes) give it very good airflow for a full-face. As one rider put it, it has “about as much airflow as any modern, full coverage enduro helmet”. The Smith AirEvac channels work well with goggles to prevent fogging. The Hardline’s vents are fewer and more oriented for high-speed airflow; the helmet does stay cool enough on downhill runs, but you’ll notice less breeze when pedaling uphill. In short, the Mainline vents more and is cooler in mixed pedaling/downhill riding, whereas the Hardline vents are adequate for high-speed DH but it can get warmer if used on long climbs.
Use Cases: Both helmets are ASTM F1952 downhill certified, so they meet high-impact standards. The Mainline is marketed as an all-round enduro/DH helmet – ideal for riders who want DH-level protection but also climb or pedal rides. The Hardline is aimed purely at aggressive downhill and freeride. It adds extras like the collarbone zone and break-away visor that you probably don’t need on a cross-country ride. If you mostly lap bike parks or race gravity events, the Hardline gives maximum protection. If you do mixed riding (shuttles, enduro races, or serious trail rides), the Mainline’s lighter weight and ventilation may be more comfortable.
Personal Impressions: In our experience, the Mainline feels lighter and more minimal on the head. It encourages you to push the pace, yet never feels bulky. The Hardline feels “heavy-duty” – you notice the weight and solid construction as soon as you put it on. On long downhill days, the Hardline’s padding and protection feel reassuring, but it can feel a bit stifling on long climbs or gentler trail sections. As one tester noted, the Mainline’s extra breathability makes climbing in the 60–70°F range easy, while the Hardline is more of a dedicated DH helmet.
Summary: In choosing between them, consider your riding style. The Smith Mainline MIPS is ideal for riders who want a versatile full-face for enduro and trail, combining light weight (770 g) and high ventilation with certified DH protection. The Smith Hardline Composite is for riders who value maximum downhill safety features – its composite shell, collarbone-crumple zone, and sturdy build give extra peace of mind on steep, rocky descents. Both are premium helmets with high-end features; the Mainline excels in comfort and breathability, while the Hardline excels in sturdiness and impact protection.
