Trail-Tested: My Review of the Smith Shift Split MAG Photochromic Sunglasses for Mountain Biking

I was honestly surprised at how lightweight the Smith Shift Split MAGs were the first time I tried them. They’re so light that I pretty much forget I’m wearing them, even on long rides. I don’t feel any pressure points, there’s no bouncing around, and no slipping, even when things get sweaty.

The adjustable nosepiece makes it easy to dial in the fit, and they’ve worked well with every helmet I’ve worn, with no weird gaps or interference (I currently wear the Giro Manifest). I have a medium-sized face and they sit just right—not too big, not too snug. Overall, they’ve been super comfortable for everything from short spins to full-day rides.

The lenses on the Shift Split MAGs are really good. Everything looks super crisp and clear, and I haven’t noticed any weird distortion or blurriness, even out at the edges. The photochromic lens has been awesome for all trail conditions. It adjusts pretty seamlessly, so I’m not squinting in bright light or struggling to see in darker sections (more on this below).

I also really like how much coverage these glasses give. They sit high enough on my face that I never catch the top of the frame in my field of vision, and the wraparound shape offers good protection without feeling bulky. Peripheral vision is wide open, which I definitely appreciate on tight switchbacks or trails where the lines are a bit interpretive. All in all, visibility feels very natural, I almost forget I’m wearing them.

This was the main reason I went with the Smith Shift Split MAGs, and honestly, the photochromic lens has been a game changer. It adjusts automatically depending on the light, so I can head out for a ride early in the morning, hit shaded forest sections, and finish in full sun without ever needing to swap lenses or take them off.

The transition between light and dark isn’t instant, but it’s quick enough that I don’t really notice it happening – it just works. I’ve never found myself wishing they were lighter or darker, which hasn’t been the case with other “do-it-all” lenses I’ve tried. If you ride in mixed conditions like I do, these lenses are magic.

Fogged-up lenses are the worst, especially on slow climbs or humid days, so I was really curious to see how these would perform for me, someone who sweats a lot! I’m happy to say the ventilation on the Shift Split MAGs is really good. Even on sweaty uphill grinds or stop-and-go rides, they’ve stayed clear for the most part. I’ve had a little bit of fogging here and there if I come to a complete stop and I’m totally drenched, but it clears quickly once I’m moving again.

There’s enough space between the lens and my face to let air flow through, and I think the split-frame design actually helps keep things breathable without feeling too open or exposed. Overall, they’ve handled fog way better than other glasses I’ve worn.

The Shift Split MAGs have held up well so far, but I’ll be honest, they do feel a bit fragile. The frame is super lightweight, which is great for comfort, but it doesn’t exactly scream bombproof. I’ve been careful with them (always storing them in their case), and the lenses haven’t scratched yet, even after a few accidental drops.

They’re definitely not the kind of glasses you can just toss around and forget about but if you treat them with a little care, they seem to hold up just fine.

I’m a fan of how the Shift Split MAGs look. They’re sleek without being too flashy. They have more of a performance vibe than casual sunglasses, but they’re still low-key enough that I don’t feel like I’m wearing space goggles at the trailhead.

One of the coolest features is the magnetic lens swap system. The lenses snap in and out of the frame with a satisfying click, making it (moderately) easy to switch lenses without fumbling with tricky clips or frames. That said, I found the process isn’t quite as quick and effortless as the marketing makes it sound. Still, it’s a well-designed system that beats traditional lens swaps and gives you flexibility for other lenses when you need it.

If you prefer a full-frame design that is a little sturdier, check out the Smith Shift MAGs. It’s essentially the same as the Split model, but just has framing on the underside, making it slightly heavier and potentially reducing the field of vision a bit.

The Smith Shift Split MAG sunglasses are definitely an investment—they’re not cheap. But they do come with a high-tech photochromic lens plus a bonus clear lens, giving you versatility for all kinds of light conditions.

With their combination of comfort, advanced lens tech, and sleek design, personally I think these glasses offer solid value for avid mountain bikers who take care of their gear. That said, if you’re a more casual rider, tend to be hard on your stuff, or are watching your budget, there are more affordable options out there that still deliver great performance.

🚵 How they compare to other mtb sunglasses

The Smith Shift Split MAG’s are just one option for good photochromic sunglasses. There are a few other contenders out there that riders love, so here is a quick side-by-side comparison against two other popular picks I’ve seen on the trails: the Smith Bobcat and the POC Devour Photochromic.