Give credit where credit's due. Thank your mom, your legs, and your gear for giving you the opportunity to land that rocky gap. Made for going big, going fast, or both, the Smith Mainline is our pinnacle, downhill certified enduro bike helmet. Safety innovations like Koroyd™ and MIPS® provide energy-absorbing impact protection so you have the confidence to get aggressive on the trail. It doesn't matter if you're slaying the EWS in Whistler or suffering through the last stage of your local enduro race, you need a breathable, lightweight helmet that pairs well with goggles and fits like a glove. The Mainline integrates with your bike goggles for efficient venting and fog-free vision. Multiple pad sets including liners and neck-rolls let you customize the fit.
- 21 fixed vents for consistent airflow
- Adjustable visor
- Hybrid X-STATIC® / XT2® anti-bacterial performance lining for odor resistance
- Weight: (Size M, MIPS®): 27 oz / 77 g
- Sizes: S - 51-55cm, M - 55-59cm, L - 59-62cm
- Aerocore™ construction featuring complete Koroyd® coverage for lightweight, energy-absorbing and ventilated impact protection
- MIPS® Brain Protection System reduces rotational forces caused by angled impacts to the head
- CPSC CE EN 178 and ASTM F1952 downhill certified
Fit / Integration
- Designed for ultimate integration with Smith performance goggles for maximum comfort, venting and storage convenience
- AirEvac™ ventilation system integrates with Smith goggles for fog-free lenses
- Three washable cheek pad kits, two crown liners and two neck rolls let you fine tune the fit
- D-ring chin strap fastener for a snug fit
Occasionally, without notice, manufacturers change product design and/or specifications.
Smith Helmet Size Guide
Use the below chart and guide to find the correct size Smith helmet for you.
Head circumference (cm)
51 - 55
55 - 59
59 - 63
63 - 67
How to measure
To find the circumference of your head, place a tape measure in the centre of your forehead, wrap it around above your ears and around the back of your head. If there's a slight difference between two different sizes, always go for the tighter size.
Once you know the circumference of your head, see the available sizes shown on the product and select the appropriate one.
The majority of cycling helmets have some form of adjustment for size, usually in the form of a ratchet adjuster to tighten or loosen the straps, some helmets will also come with different thickness pads to further customise the fit.
Read our clothing size guide for more information on sizing.
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Smith Optics Mainline Mips Full Face MTB Cycling Helmet
Christmas Delivery- this product is available for Christmas Delivery
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Love it glad I went with the smith over the fox pro frame really comfortable and stylish very well made not one bad point I can pick up on would recommend to anyone wonting a full face
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