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Mainline Mips Full-Face Helmet

4.656346749226006 out of 5 stars
323 Reviews
Color:Matte Midnight Navy/Sagebrush


Size Chart


Why We Like The Mainline Mips Full-Face Helmet

Smith makes their debut into the world of ultra-light full-face helmets with the all-new Mainline MIPS. Featuring extensive ventilation and lightweight yet tough construction, this helmet offers the airy feel of a half-shell while providing downhill-certified coverage for a boost of confidence on rowdy trails. Advanced protective features include Smith's unique Koroyd crumple zones that go above and beyond to disperse impact forces, as well as a MIPS protective layer that helps mitigate harmful oblique impacts.


  • Smith's lightweight full-face for enduro and downhill
  • ASTM certified for downhill mountain bike racing
  • 21 vents keep you cool during summer shred sessions
  • Koroyd layer provides superior impact absorption
  • MIPS protects against oblique and rotational impacts
  • Comes with multiple pad sizes to ensure a proper fit
  • D-ring fastener is lightweight and super secure
  • Anti-odor pads are removable and washable
  • Item runs small, so we recommend sizing up for best fit
  • Item #SMIZ99F
Shell Material
Aerocore in-mold polycarbonate
Audio Compatible
AirEvac system (21 vents)
Fit Adjustment
3 different sizes of cheek pads, 2 different sizes of crown liners, 2 different sizes of neck rolls
ASTM F1952-15, Complies with U.S. CPSC Safety Standard for Bicycle Helmets for Persons Age 5 and Older
Claimed Weight
[large] 1lb 15.6oz
downhill, enduro
Manufacturer Warranty
[sunglasses, goggles] limited lifetime, [helmets] limited 3 years, [apparel, accessories] limited 1 year

Overall Rating

4.5 based on 323 ratings

Review Summary

1 Stars - 5 reviews
2 Stars - 1 reviews
3 Stars - 20 reviews
4 Stars - 48 reviews
5 Stars - 249 reviews

Fits Slightly Small

Screen reader users: the following list provides a visual scale to illustrate the product fit. Please refer to the heading above for the fit type in text.
Runs smallTrue to sizeRuns large

What do you think about this product?


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5 out of 5 stars

May 30, 2024

Helmet works!

I like my mainline helmet. I cased a jump and landed on my head. I hurt in many places but not my head. Did its job well.


Originally reviewed on

5 out of 5 stars

May 26, 2024

Highly recommend

I have been wearing one of these helmets for about a year. It is comfortable, well vented and light. After crashing at a bike park and landing face first on a rock I can also confidently say that it offers great protection also. I broke the helmet,but walked away with only a small cut on my face. I also bought the same helmet as a replacement. If you're considering buying a mainline, get one.


Originally reviewed on

5 out of 5 stars

May 17, 2024


Great product. Don’t normally bother writing reviews but just went over the bars and landed on what would have been my face if it hadn’t been for this helmet. Body pretty banged up but not a scratch on my face/head


Originally reviewed on

3 out of 5 stars

March 10, 2024


I ordered the Mainline MIPS after weeks of researching the right helmet, and decided on SMITH, due to its reputation and quality craftsmanship. And that’s apparently clear after receiving the product. However, it arrived with a torn box and small, but noticeable rub on the face guard. And it truly appears as if the item was resold after receiving it back as a return, which is disappointing, given that it’s my first SMITH experience, now dampened by this incident. It’s more a trust thing, than anything else: why sell an open box product as “new?” As well, why, knowing that I’m a first time buyer, would a company not want that experience to be the absolute best? Great MTB Helmet though! Extremely WELL MADE!!! Quality! Ruggedness, light on the head! Outstanding aeration…just can’t give it 5 stars due to what SMITH allowed for my first time dealing with them.


Originally reviewed on

3 out of 5 stars

February 13, 2024


I might get some backlash here, but I may be the only one that hates this helmet. Pros: -Lightweight -Breathable -assorted cheek pad sizes Cons: -No rear tension for a snugger fit -Chin strap is impossible with gloves on *prefer a quicker release like the Bell Quick Air chin strap -sizing is off, the med didnt feel secure on my dome and a small was too snug -i cant pull up my goggles for a quick breather, they flop right back into your face I wore this helmet once on a longer ride and was so ticked the whole time. I fumbled with my gloves every time i wanted to take it on and off for a breather. And i know its not just me because my friend has this helmet and its annoying with the chin strap and gloves. I didnt like how lose it felt, i had to have the chin strap basically choking me and even then i just didnt like the fit. If Smith adds a rear tension adjustor and an easier way chin strap i would love it. Just not for me. Lame.

Ingrid J
5 out of 5 stars

February 6, 2024

I've owned Smith ski helmets, first Smith bike helmet.

Great fitting, great looking, confidence booster. I haven't taken a fall with the Mainline, but feel that it will keep me safe if that day comes.


Originally reviewed on

5 out of 5 stars

November 21, 2023

Favorite Full Face

Great helmet, light weight, well vented, awesome build quality. easy adjustments with interior pads for optimal fit. fits true to size. great combo with Squad XL goggles.


Originally reviewed on

5 out of 5 stars

October 13, 2023

Le casque est parfait! Il

Le casque est parfait! Il est super confortable et le design est simple comme j’aime!

Sophie L.

Originally reviewed on

5 out of 5 stars

September 8, 2023

Wow. Ultra-lightweight, super cool, full oxygen intake

This is my first new full-face helmet in 10 years and I’m blown away by it. The Koroyd construction makes it so light it’s almost strange to wear at first because it doesn’t feel like the full certified DH rated helmet that it is. The helmet is quite fitted and comes with different sets of cheek pads to adjust against your face. The medium shell fits my bean (same as my Forefront 2 and Session) and the medium face pads feel barely snug and I never notice them when riding. The chin strap is a classic DH loop and snap with a one-hand release and snugs up with strap pads to eliminate any bounce movement.The biggest features are the things you don’t notice on the trails. The helmet is so light, your neck and shoulders don’t get tired at all. And I found myself turning my head more in corners and tech trails looking for lines. We rode a full weekend of DH at Bromont, Quebec in super sunny conditions and the Mainline stayed cool the whole time. The AirEvac ventilation + Koroyd works really well. So well that I didn’t even bother to remove the helmet on the lifts. The MIPS system squeaks a bit when riding, but I stopped noticing it after a run or two. The chin guard an face opening are much larger than what I was used to with previous Giro helmet and provide a high filed of vision and airflow for breathing felt 100% normal. You could absolutely use this helmet for enduro and trail riding and not worry about breathing and air intake. (With this level of breathing I can see why SMITH has not yet released a removable chin-strap helmet). The replaceable visor clicks in to multiple positions for extra visibility or sun blocking. I’m running Squad MTB Goggles with this helmet and the combo is killer good. The integration and fit are perfect and they maintain the right airflow to virtually eliminate fogging. The helmet is shaped to retain the goggle strap to keep even but minimal pressure on your face. The face opening width is huge and the matched goggles provide an unobstructed view and I can’t even see the chin bar when riding. The Chromapop lens was outstanding in the bright sun this past weekend and really made the trail features stand out even through the forest with heavy shadows and changing light. The helmet look great and the 3 colour Matte Slate - Fools Gold - Terra is the bomb. Love the 3 tone and sharp angles. Comes with a full-size helmet bag.

Mike M.

Originally reviewed on

5 out of 5 stars

August 23, 2023

Did it’s job well

Saved my wife’s face on a fall. This helmet did its job well and bought another one.


Originally reviewed on