Topo MTN Racer 3 review

The Topo MTN Racer 3 is a solid choice for those looking for:

• A trail shoe with an ultra-roomy toebox, offering unmatched toe splay and generous vertical space—perfect for runners with broad, high-volume feet.
• A versatile trail shoe that excels on easy to moderate terrain, delivering outstanding grip with its Vibram Megagrip outsole.
• The familiar roomy feel of Altra trail shoes but with a higher heel-to-toe drop.

We believe the MTN Racer 3 falls short for those seeking maximum cushioning on the trails. Its midsole offers good protection, but for some runners, it may not be enough. If that's you, we recommend the Topo Ultraventure 3 or, for an alternative outside this brand, the Nike Zegama 2.

Additionally, we think the MTN’s ultra-wide toebox is a dealbreaker for many. While it’s fantastic for runners with broad feet, those with narrower or lower-volume feet will struggle with an sloppy fit. The HOKA Speedgoat 6 offers a snug fit while retaining the Vibram Megagrip outsole and the same versatility.

In our experience, the MTN Racer 3’s midsole provides good support for long distances, featuring a 33.5 mm stack in the heel. While it’s not as towering as some maximalist options like the ASICS Trabuco Max 3, we believe it offers enough protection for most heel strikers venturing onto the trails.

According to our measurements, the forefoot stack in the MTN Racer 3 sits above average at 26.6 mm, which aligns with Topo’s design philosophy favoring midfoot and forefoot strikers. This front cushioning provides ample protection underfoot while remaining low enough to maintain a slightly-grounded feel on the trails.

Every Topo Athletic shoe we've tested in the lab so far has featured an advertised 5-mm drop, and the MTN Racer 3 is no exception. However, our precise measurements revealed a slight discrepancy: we clocked 6.9 mm, which makes it a bit more accommodating for rearfoot strikers.

The midsole, unfortunately, doesn’t feature Topo’s Pebax-based foam like the Cyclone 2. Instead, it relies on the training-oriented ZipFoam—a decision that left us questioning the "Racer" name. If it’s meant to be race-ready, why not use a superfoam?

That said, let’s focus on what’s here rather than what’s missing. The ZipFoam midsole isn’t a disappointment by any means, delivering a well-cushioned, moderately bouncy ride with a durometer reading of 21.5 HA. But again, while we’re content, we believe that a Pebax midsole would have been a more fitting choice for a shoe with "Racer" in its name.

We placed the MTN Racer 3 in the freezer for 20 minutes, and it returned 21% firmer—that's a good result!

The insole, made by Ortholite, measures 4.5 mm thick.

The heel has a slight curvature, though we believe this isn’t the best trail shoe for heel strikers.

Up front, the forefoot boasts a pronounced rocker, ensuring smooth transitions for runners who land in the midfoot area.

One of the main reasons for choosing a Topo Athletic shoe is its foot-shaped toebox—designed for natural toe splay and a more anatomical fit.

To confirm its spacious feel, we created a toebox mold and measured its widest point. Our digital calipers read 98.3 mm—definitely roomy, though only slightly above average. While it provides plenty of space, we need to do more test!

For runners with wide feet, this is a game-changer.

We measured an expansive 82.2 mm at the big toe, and in our experience, it’s nearly impossible to feel cramped in this ultra-spacious toebox. It’s as far from a tapered design as a shoe can get—offering unmatched freedom for natural toe splay.

Even more impressive, the vertical space is exceptionally generous at 31.8 mm.

This makes the MTN Racer 3 perfect for high-volume feet, but in our view, some runners may find it too loose, and those who prefer a snug, foot-hugging fit will feel discouraged by its roomy design.

When it comes to stability, this shoe delivers two vastly different experiences depending on footstrike. In our view, even midfoot and forefoot strikers with slight pronation will find it manageable—its broad landing platform and moderately-high torsional rigidity help maintain a balanced ride.

However, heel strikers may struggle unless they have a neutral gait. The rear of the MTN Racer 3 doesn't offer the same level of support.

Torsional rigidity is surprisingly high, even without a plate in the midsole. Based on our findings, this comes from the thick foam slab and outsole design, which enhances longitudinal stiffness while maintaining strong torsion resistance—earning a high 4/5 in our assessment.

Through our evaluation, we found that the heel counter strikes a harmonized mix of comfort and support, scoring 3/5—comparable to a road daily trainer.

We mentioned earlier that this shoe favors midfoot and forefoot strikers over heel-first runners, and the midsole dimensions play a key role.

The forefoot measures a generous 115.0 mm—noticeably wider than the rear compared to the average—providing outstanding stability, even at high speeds on rugged trails.

As we noted earlier, the heel is exceptionally narrow for a trail shoe, measuring just 82.3 mm. Due to this, it's best suited for neutral runners for those landing with the heel, though even they may find it slightly unstable, especially on uneven terrain.

The outsole features strategically placed grooves that enhance longitudinal flexibility. This design makes the shoe impressively adaptable for daily wear or hiking, even with its highly-cushioned midsole. In our 20-degree bend test, it registered a remarkably low 22.2N!

When it comes to weight, the MTN Racer 3 doesn’t stand out, but there’s little to criticize. At 10.10 oz or 286g, it sits right around the average.

While Topo Athletic could shave off some grams, weight reduction isn’t the top priority for trail running.

We weren’t sure about the MTN Racer 3’s ventilation at first. The upper lacks large, visible airflow openings—often a hallmark of ultra-breathable shoes. However, the mesh looked incredibly thin, so we turned to lab testing to get a definitive answer.

Running the shoe through our smoke-pumping machine, we found that airflow was superb for a trail model, earning a 4/5 score. Smoke passed effortlessly through the upper, even along the toebox sides, suggesting impressive breathability despite the lack of conventional perforations.

Curious to learn more, we moved the upper over a bright light. The results confirmed our suspicions—the mesh is strikingly thin, which enhances ventilation but also raised concerns about long-term durability.

Next, we examined the material under a digital microscope.

We found a tightly woven, crisscrossed mesh pattern that allows air to escape more efficiently than most trail shoes, despite the absence of large holes. This clever construction boosts breathability without sacrificing too much structure.

Finally, assessing the upper by hand, we discovered a stretchy, lightweight mesh. The reinforced heel adds some extra structure, but again, the overall build maybe felt less rugged than expected in a trail running shoe.

Our expectations for the toebox durability test weren’t particularly high, and unfortunately, the results confirmed our concerns. After testing, we discovered noticeable damage and rated it 2/5—a disappointing outcome for those expecting a tough, trail-ready upper.

The heel counter also scored a disappointing 2/5, raising even more concerns in our lab. For us, this shoe is far from ideal for runners who frequently experience premature wear in the upper, regardless of the specific area.

Moving to the outsole, we had higher expectations as we immediately spotted the iconic Vibram logo—a name that never disappoints in trail running. From our perspective, that alone signaled a reliable grip, but we were eager to put it to the test.

True to its reputation, the traction from Vibram Megagrip proved exceptional across a variety of surfaces. Despite featuring a dense, ultra-durable rubber, which we measured at 87.0 HC, the outsole maintained a solid grip without feeling overly rigid. We also found fantastic rubber coverage with just a few spots of exposed midsole.

The Vibram Megagrip outsole far surpasses the upper in durability. Through our evaluation, we measured an impressive minimal wear of just 0.5 mm—an ultra-durable design that reinforces one of the MTN Racer 3’s most standout features, especially at its price point.

Using our vernier calipers, we measured the outsole thickness at 1.8 mm—a reasonable figure considering the impressive wear resistance of Vibram Megagrip.

To wrap up our outsole analysis, we measured the lugs at 4.2 mm deep—a solid choice for a versatile trail shoe.

They perform well on easy terrain and excel in moderate conditions. In our view, the well-spaced heel lugs allow for occasional or emergency use in muddier, more demanding trails.

While the midsole isn’t Topo’s most energetic, we believe the combination of a top-tier Vibram outsole and a comfortable-breathable upper justifies the price of the MTN Racer 3.

Sadly, Topo omitted reflective elements in the MTN Racer 3—something we always find disappointing in a trail shoe, especially for those who venture out in low-light conditions.

A signature design choice from Topo is the dual lace loop near the top of the tongue—an upgrade from the average single-loop setup most shoes place closer to the middle.

We also measured a tongue thickness of 5.6 mm, which strikes a well-balanced mix of weight and comfort. Even during our longest tests, the padding felt sufficient—at no point did we feel the need for extra foam to protect the instep.

The MTN Racer 3 features a fully gusseted tongue, which is our preferred setup for trail shoes, as it effectively prevents debris from slipping between the tongue and the shoe’s medial or lateral sides.

Topo Athletic skipped the heel tab on this model—a small detail that would have complemented its trail-ready design. On the flip side, it includes two unusual heel cutouts that serve a functional purpose, acting as gaiter attachments for the brand’s custom-locking system.

We found that the insole isn’t glued to the last, and when combined with the ultra-spacious toebox, it allows nearly any third-party footbed to fit effortlessly into the MTN Racer 3. However, this means sacrificing the premium Ortholite footbed.