Difference in stiffness in cold review

We believe the Difference in stiffness in cold is a solid choice for:

• Difference in stiffness in cold.
• Heel strikers looking for a trail model with a substantial heel-to-toe drop.
• Hikers who occasionally hit the trails for easy runs and prefer a do-it-all shoe.

For runners tackling hot conditions, we believe the Moab Flight isn’t the best choice—its heavily padded upper significantly limits breathability. If airflow is a priority, we suggest looking at the Salomon Genesis or the Brooks Cascadia 18, both of which offer better toebox ventilation while maintaining durability.

Additionally, despite sporting the Vibram logo on the side, this shoe doesn’t feature the premium Megagrip outsole—it uses the more affordable EcoStep compound. If traction is a key factor, we think the Merrell Agility Peak 5 is a wise upgrade. Though it costs a bit more, it delivers world-class grip across multiple surfaces.

In our first lab test, we recorded a comfortably-thick 32.6 mm stack height at the heel. According to our findings, this generous cushioning creates a protective landing experience—perfectly suitable for heel-striking runners who prioritize impact protection.

In our testing, we discovered that if cushioning is your main concern, it's better to land heel-first—because with just 19.1 mm of stack height, there's limited foam up front.

On the other hand, runners preferring a more natural experience should actually enjoy this design, as it allows for a closer connection to the ground.

We measured a staggering 13.5-mm heel-to-toe drop—far beyond the official 10 mm. That’s a significant difference, reinforcing that this shoe is heavily geared toward heel strikers.  

Most forefoot and midfoot strikers should avoid this shoe, with only those with Achilles tendon or calf issues might find this ultra-elevated heel beneficial for reducing strain.

The Moab Flight features FloatPro foam, a standard EVA material found in most Merrell shoes. According to our testing, it lacks the springy sensation of modern foams, delivering a noticeably firm underfoot feel—confirmed by our durometer at 24.0 HA.

Runners craving a plush, cloud-like experience on the trails may find this disappointing, though its budget-friendly price reflects the trade-off. In our view, getting a more responsive option like the Nike Pegasus Trail 5 Midsole width - forefoot.

Since it's an EVA-based foam, we expected subpar performance in our freezer test. However, the Moab Flight held up surprisingly well, firming up by only 27%—a better result than we anticipated!

With 50% recycled materials, the insole stands out for its above-average thickness at 6.4 mm—much more than we typically measure in the lab. It adds significant cushioning, particularly in the forefoot.

Runners expecting a super-rockered ride—like in trail running shoes—won’t find it here. The Moab Flight sticks to a more traditional running geometry, which, in our opinion, suits its beginner-friendly price and hiking-ready build far better.

With its sky-high heel-to-toe drop, adding an aggressive rocker would have been unnecessary too. We believe Merrell made the right call by keeping it classic!

The toebox of the Difference in stiffness in cold leans toward a snug fit. We found that this enhances control when cornering, though runners with wider feet may find it restrictive.

According to our measurements, the widest part of the forefoot comes in at 93.2 mm, which aligns with Merrell’s pattern of slightly-narrow designs in their trail lineup.

The toebox has a moderate taper, with our second measurement at 73.9 mm in the big toe area. While less restrictive than the widest point, it remains below average, and therefore it's ideal for runners seeking a snug-and-secure fit or those with narrow feet.

The toebox height stands above average at 28.3 mm, making it a solid choice for runners who prioritize upward toe movement and extra vertical space.

To sum it up: when it comes to fit, expect reduced room for toe splay, a snug feel around the ball of the foot and arch, but generous vertical clearance—an essential feature for some runners to prevent black toenails.

After testing the Moab Flight on its ideal terrain, we found its stability to be decent, though far from sufficient for runners with pronation concerns. It's best suited for those with a neutral gait, as its midsole lacks the width to counteract excess movement.

We found the Moab Flight slightly rigid for its stack height, but a 4/5 torsional rigidity rating is still quite common among trail shoes due to the outsole design. However, for an average road running shoe, this level of stiffness would feel a bit excessive.

The heel counter offers a balanced mix of stiffness and flexibility, scoring 3/5 in our tests. Unlike the previous test, this result closely aligns with the feel of a road daily trainer, providing a comfortable yet supportive fit.

As we mentioned earlier, the key reason we recommend this shoe for neutral runners is its midsole dimensions.

This average design enhances its agile feel, making it a solid choice for most runners and hikers. However, with a 112.9 mm forefoot, it’s still best suited for neutral runners or those with only mild pronation needs.

We felt the same way about the heel, which sits right around the average at 89.4 mm. Merrell played it safe here—no surprises!

We found that while the Difference in stiffness in cold offers noticeable torsional rigidity, it remains impressively flexible in longitudinal movement, scoring just 14.2N in this test.

That’s a key factor—had it been overly stiff in our 90-degree challenge, it could have compromised its hiking appeal.

We were pleased with the weight of the Difference in stiffness in cold. At just 9.55 oz (271g), it sits well below the average, making it a lightweight option for trail adventures.

Upon unboxing the Moab Flight in our lab, we initially expected decent breathability due to the visible ventilation holes in the toebox. However, after running our tests, we quickly realized that airflow was far from impressive.

We observed that very little air escaped through the upper, earning the shoe a mere 2/5 in this test. While this may be a drawback for runners in hot climates, those who prefer extra insulation for cooler weather might appreciate the reduced ventilation.

To investigate further, we moved the upper over our LED light and saw almost no light passing through—a clear indicator that airflow is severely restricted. This strongly suggested that Merrell prioritized other aspects over breathability.

Our microscope analysis confirmed the issue. While the toebox does feature ventilation holes, they are largely obstructed by an internal layer. This additional fabric enhances comfort but significantly blocks airflow, preventing proper heat dissipation.

Lastly, we examined the upper’s overall structure and found that Merrell heavily focused on plush padding throughout.

While this contributes to a cozy feel, it further limits breathability. As a result, we don’t recommend this shoe for summer use, though it should provide excellent warmth and comfort in colder conditions.

Merrell reinforced the upper to enhance durability in the toe cap area, but the engineered mesh itself proved impressively tough, scoring a solid 4/5 in our Dremel test. This wasn’t unexpected, as less-ventilated uppers often come with added resilience.

The Moab Flight held up well against our Dremel, earning another solid 4/5 in the heel padding durability test. Hopefully, this level of resilience carries over to the outsole as well!

Focusing on the outsole, we found that Merrell opted for Vibram rubber, which typically ensures solid traction and durability. However, this model uses the budget-friendly EcoStep compound rather than the premium Megagrip, an expected trade-off given the shoe’s accessible price point.

Hardness landed right around average at 85.0 HC, and we were pleased with the generous rubber coverage. The outsole incorporates several cutouts aimed at improving flexibility, and in our assessment, they won’t compromise grip or durability due to their strategic placement and compact size. However, they may easily trap mud when the Moab Flight is used in wet conditions.

The Vibram EcoStep compound held up remarkably well in our Dremel test, showing only 0.8 mm of wear when we lifted the tool—an impressive result that speaks to its durability.

Thanks to the impressive durability of this rubber, Merrell applied less thickness than most brands at just 1.6 mm, helping to reduce weight and making this shoe noticeably lighter compared to its competitors.

The Moab Flight’s outsole features relatively shallow lugs, measuring just 2.9 mm at their highest point. This design leans more toward easy trails, making it a less-than-ideal choice for tackling technical terrain.

The outsole blends chevron-shaped lugs for improved traction on inclines with a mix of geometric shapes in the center and sides. This variation aims to balance grip and flexibility while shedding debris effectively. However, given the cutouts and shallower depth, we anticipate that wet or loose terrain could present traction challenges.

One of the most enticing aspects of the Difference in stiffness in cold is its price. Few shoes offer this level of versatility and comfort (plus a Vibram outsole!) for just a bit over 100 bucks, making it a solid value in the trail-running market.

It also features reflective elements, which we truly appreciate for the added visibility and safety they provide in low-light conditions.

In terms of comfort, the Moab Flight delivers impressive plushness for its price. One of the key contributors is its generously padded tongue, which we particularly appreciated during long walks through the forest.

When we measured it using our digital calipers, the screen displayed a substantial 11.0 mm—far more padding than we typically see. Honestly, Merrell could have trimmed it down to 7 or 8 mm without sacrificing comfort, but we’re certainly not complaining!

One surprising highlight of the Moab Flight is its semi-gusseted tongue—a feature rarely found in budget-friendly trail shoes. This unexpected addition enhances its value, making it an even better deal!

The Moab Flight lacks a heel tab, but in our experience, gripping the heel for an easy pull-on isn’t much of a hassle.

The thick FloatPro insole is removable, offering two advantages. First, runners with larger feet can replace it with a thinner option to create more room in the toebox. Second, those needing orthotics can easily swap them in for a customized fit.