Smith Mainline Review: The Best Full Face Helmet For Mountain Bikers?

The Smith Mainline has been my full face mountain bike helmet of choice for several seasons now and don’t see myself switching to a different one anytime soon. I know helmets are one of the most important purchases for your mtb gear get-up, so in this Smith Mainline review, I give my honest opinions about what I love about it and what I don’t (spoiler alert: not much!)

As someone who rides all types of terrain and trails from mellow cross-country tracks (which I wear my Giro Manifest helmet for) to rowdy bike park riding (where the Mainline comes in), I’ve tried and tested out a lot of different lids.

Honestly and truthfully, the Smith Mainline is one of the most comfortable and secure-feeling helmets I’ve worn. Read to see whether this is the helmet for you!

Smith Mainline pros

Smith Mainline Cons

Smith Mainline Performance

A helmet can look great and be super comfortable to wear, but what matters the most is its safety. It’s gotta keep your head intact if and when you go OTB, right? Here are the main safety and performance features of the Smith Mainline:

Safety

Certifications

The Smith Mainline is one of the safest full face mountain bike helmets out there. It’s been approved for a few safety ratings including:

• ASTM F1952 Downhill Standard approval rating, the highest safety rating for mountain bike helmets.
• CPSC CE EN 1078, a Consumer Product Safety Commission safety approval for bicycle helmets.
• NTA-8776, a safety approval for e-bike use.

In short, the Smith Mainline has been put through rigorous testing to ensure your noggin is protected during a high-speed crash.

MIPS Technology

This helmet also utilizes MIPS Technology, which most mountain bike helmets these days should come with. MIPS stands for Multi-Directional Impact Protection System. This means that MIPS helmets – including the Smith Mainline – have a thin, plastic liner that is designed to protect your head against rotational forces during a crash.

You can learn more about how the technology works on the MIPS Protection website.

KOROYD Technology

In addition to Mips, the Smith Mainline also uses KOROYD technology. This lightweight material is formed into a proprietary honeycomb design. It has two main functions: to enhance impact protection while maintaining optimal ventilation and lightweight construction.

In theory, this unique KOROYD technology is engineered to absorb and dissipate energy upon impact, thus reducing the forces transmitted to you – the rider’s – head.

I also think it looks cool!

Full Face Coverage

A full face helmet should protect your full face, right? The Smith Mainline has great coverage from the back of the head to your pearly whites. It provides protection of your face, jaw, and chin without feeling like you’re locked in a cage.

I also appreciate the large cut-out in front of the mouth area. This helps reduce fogging and makes it easier to talk to your friends.

The visor

The Smith Mainline has an adjustable visor, however, unlike most ‘normal’ mountain bike helmets, this one requires you to manually adjust it with a dial. This is just another safety feature built into the Smith Mainline. The dial prevents the visor from slipping down or getting caught in a gust of wind as you’re bombing downhill.

D-Ring Chin Strap

True to downhill full face helmets, the Smith Mainline has a D-ring fastener as a chin strap. It’s not quite as easy to use as the magnetic fastener many mountain bike helmets come with these days (like the Bell Super DH), but this type of fastener is safer because it won’t inadvertently come undone during a crash.

I gave it 4/5 starts because it’s a little annoying to fasten and unfasten, especially with gloves on, but I guess that’s a small price to pay for safety.

Smith Mainline Comfort & fit

A mountain bike helmet has to be safe, but it also has to be comfortable, right? Full face helmets might not be the most cushy thing in the world to wear on your head, but here’s how Smith has designed the Mainline to be tolerable:

Comfort

For a full face helmet, the Smith Mainline is pretty darn comfortable. The crown is lined with nice padding that is removable so you can rinse it out after a few bike park days. It also has thick cheek pads and a neck pad for extra cushioning (both of these are removable as well) as well as padding under the chin strap, which is a nice touch.

I also love that the Mainline is quite lightweight for what it is. It doesn’t feel like you’re wearing a bucket on your head – instead, it feels like you’re wearing a helmet that was designed to be both comfortable and protective.

Fit

The Smith Mainline comes in three different sizes: small, medium, and large. You can use their size chart below to determine which size you are.

This helmet also comes with three different cheek pad sizes and two neck liner pad sizes so you can get a snug fit. It is a bit of a waste to have extra sets of pads you won’t use, though…

The reason I give the Smith Mainline only four stars for fit is because it doesn’t have a fit dial at the back of the head like most mountain bike helmets do. I’m not sure if this has to do with safety (a dial could come loose during a crash I suppose) or something else, but it is a feature I miss. I often catch myself reaching to the back of my head to snug up my helmet a bit only to remember that the Mainline doesn’t have a fit dial.

Ventilation

It feels weird to give a full face helmet 5/5 stars for ventilation, but the Smith Mainline deserves it! I don’t know if it’s the honeycomb KOROYD design or the 21 vents that promote good airflow, but the Mainline doesn’t feel stuffy or like a sweatbox.

Of course, the ventilation isn’t going to be as good as a ‘half lid’, but for a full face it’s pretty darn good.

Additional Features

The Smith Mainline has a few other features that are worth mentioning. They include:

Is this helmet for you?

I really love my Smith Mainline and it’s the full face helmet I will continue to wear at bike parks and on rowdy downhill trails for seasons to come, I suspect.

I love that I can trust it to protect my head and face if I crash because I know it has been tested rigorously for safety. I also love that it’s actually comfortable to wear, even on long lift-served days.

I know this helmet isn’t the cheapest or most budget-friendly full face helmet out there, but you only get one brain, right? For me, the price tag is worth feeling safe and confident on the trails.

Not sure what to look for in a helmet? Check out my tips on how to choose a mountain bike helmet so you can get the ride one for your rides.

How it Compares

Not yet sold on the Smith Mainline? Here’s how it compares to three other popular downhill full face helmets: The Troy Lee Designs Stage, the Fox Proframe, and the POC Coron. Honestly, the main differences between these three helmets are the weight, price, and chin strap fasteners.

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Have you tested out the Smith Mainline mountain bike helmet? What do you love or dislike about it? Would you add anything to this review? Leave a comment below!