Under Armour SlipSpeed Mega review

We tested the Under Armour SlipSpeed Mega and found it to be a solid choice for:

• Weekend warriors who appreciate its clean aesthetics, looking for a shoe that works for casual runs and daily wear.
• Those who appreciate the BOA system from their cycling shoes and want a fairly-priced option for occasional running.
• Frequent travelers who value the convenience of a single shoe for gym sessions, city walks, and the occasional easy run in the park.

We believe the SlipSpeed Mega is not the best choice for serious running. It struggles with performance due to its heavy build and lack of responsiveness, making it unsuitable for anything beyond easy jogging. Instead, we recommend the ASICS Novablast 5 or the Nike Pegasus 41—both are significantly lighter and provide a much snappier ride.

Additionally, we think the shoe’s poor breathability could be a dealbreaker for those in warm climates. Its thick, unventilated upper traps heat, making it a bad choice for summer runs. If ventilation is a priority, the Brooks Ghost Max 2 offers far superior airflow while also delivering a more performance-ready ride.

The SlipSpeed Mega firmly belongs in the maximalist category, boasting a towering 40.7 mm stack height in the heel—leaving no doubt about its ample joint protection.

Naturally, with over 4 cm of cushioning, ground feel is virtually nonexistent even for heavier folks.

We found that the forefoot also packs a substantial amount of cushioning, measuring 28.8 mm in thickness. This confirms that protection isn’t just focused on rearfoot strikers—it extends across all footstrike patterns for a well-cushioned, impact-absorbing ride.

Marketed toward casual runners and weekend warriors, we had no doubt the drop would cater to heel strikers. And sure enough, it comes in at a steep 11.9 mm!

The SlipSpeed Mega features Under Armour’s Flow cushioning—an average EVA foam with a semi-firm feel. We tested it with a durometer reading of 24.2 HA, confirming its moderate density.

In our opinion, this somewhat firmer setup works well for easy runs and long walks. Given the high stack height, we understand why they opted for a more stable feel. However, if you're after a plush-and-pillowy ride, this isn't the right shoe for you.

We placed the Under Armour SlipSpeed Mega in the freezer for 20 minutes and were pleased with the results—it only became 10% firmer, maintaining its cushioning and responsiveness despite the cold.

The insole has a standard thickness of 4.4 mm.

One of the most intriguing aspects of the SlipSpeed Mega is that it’s one of the few maximalist shoes without an overly rockered design—something we found surprisingly refreshing.

While it's true that the heel has a noticeable flare, the front and rear curvatures remain mild. In our assessment, this design works well for those seeking a do-it-all, gym-ready, and casually-versatile shoe for easy runs, indoor workouts, or everyday walks.

We have an amazing method to replicate the toebox and take multiple measurements, but with this shoe, we knew right away—it was going to be narrow. The moment we unboxed it and slipped it on, the snug fit was unmistakable.

Our first measurement came in at 92.9 mm. While not extremely tight, it clearly suggests that Under Armour designed this shoe with a narrow last, making it less suitable for those with wide or high-volume feet.

Our second measurement confirmed it: at 71.7 mm, there’s minimal space for toe splay, reinforcing the shoe’s narrow-and-secure fit.

Lastly, we measured the toebox height, which came in noticeably lower than average at 25.0 mm.

This third measurement confirms that the shoe is best suited for small, low-volume feet—perfect for those who find most shoes too spacious for a secure fit.

This shoe puts your feet impressively high—over 4 cm above the ground—which naturally introduces some instability. However, Under Armour countered that with a broad-and-supportive midsole, high torsional stiffness, and a snug fit, striking a balanced middle ground.

And for the gym? If you ask us, it works for light workouts or machine-based exercises, but the ultra-thick stack height and limited room for toe splay makes it less than ideal for serious lifting.

The Under Armour SlipSpeed Mega doesn’t have a carbon plate, but with its 5/5 torsional rigidity rating, it might as well! It’s nearly impossible to bend or twist.

The "Slip" in the name refers to the slip-on heel design, which allows it to fold completely. Because of that, a 1/5 score was inevitable!

The forefoot is wide but not extreme. We measured it at 117.5 mm—slightly broader than most running shoes yet narrower than the average maximalist model, which typically exceeds 120 mm.

The heel feels wide—and it is—measuring 95.0 mm. We believe Under Armour made a smart design choice here, as the added width enhances stability for casual runners who tend to heel strike or those using it primarily for walking.

With such a massive foam stack, a super-flexible build was not going to happen, but we still hoped for more give than the 34.7N result. A bit more flexibility would have made it better suited for everyday wear or easy runs.

There’s no way to sugarcoat it—the SlipSpeed Mega is heavy. At 11.70 oz (332g), it ranks among the heaviest shoes we’ve tested, making it best suited for easy-paced runs or casual wear rather than anything performance-related.

In our view, a few well-placed midsole and outsole cutouts could shave off an ounce or two while also improving longitudinal flex.

Under Armour claims the SlipSpeed Mega features a breathable upper, and we were eager to put that to the test. At first glance, it didn’t look breathable at all, so we were curious to see if performance matched the marketing.

Once we hooked it up to our smoke machine, the results were clear—airflow was nonexistent. The smoke barely escaped, leading us to assign it a 1/5 breathability rating, which is as low as it gets in our lab tests.

To further investigate, we moved the upper over a bright light source. Again, very little light passed through, reinforcing what we had already found—this shoe traps heat. While that may work well for cold-weather use, it’s far from ideal for summer workouts.

Wanting a deeper explanation, we turned to our microscope.

What we found was striking—the upper’s dense material closely resembles what we see in Gore-Tex running shoes. The tightly woven fabric leaves little room for air to escape, confirming the shoe's limited ventilation.

We also noted that the upper has zero stretch, yet it delivers impressive comfort. Even the toebox is padded, which further restricts airflow but creates a luxurious, cozy interior.

The lack of ventilation holes and the thick upper come with a major advantage—outstanding toebox durability. The SlipSpeed Mega aced our test, earning a top-tier 5/5 score!

This shoe is all about extremes—it doesn’t do middle ground. A 1/5 score in heel padding durability only reinforces that!

Want more proof of its extreme design? Let’s talk about the outsole—it’s just as unconventional. Instead of traditional rubber, Under Armour used a rubberized EVA compound, essentially blending midsole foam with firm rubber.

We measured it at 60.0 HC, confirming its noticeably softer composition compared to standard rubber from running shoes. In our opinion, this gives the shoe a gentle feel underfoot, but at the cost of grip and long-term durability.

In fact, the rubberized EVA practically disintegrated under our Dremel, suffering 7.0 mm of damage—an extreme but expected result for this type of outsole. This confirms that the SlipSpeed Mega wears down quickly on abrasive surfaces and it's better suited for casual use.

Despite its drawbacks, we found the price to be fair considering the market. Few running shoes feature a BOA system, and this one adds versatility. For those who match its strengths—snug fit, cold weather or indoor use, and max stack height—it delivers solid value.

Unfortunately, Under Armour left out any reflective elements.

The tongue is well-padded at 6.0 mm, and we never experienced excessive pressure.

The BOA system made it effortless to achieve the perfect lockdown, and if overtightened, adjusting it takes just a quick turn in a couple of seconds.

The SlipSpeed Mega’s distinctive design extends to its tongue, which features a sock-like construction that gives the impression of one shoe nestled inside another.

We found an extended heel collar design in the SlipSpeed Mega that supports the Achilles tendon while securely gripping the heel, making entry effortless.

You can remove the insole if needed—it’s not glued in. This also reveals the shoe’s instructions for its dual-mode functionality and highlights another big advantage: this shoe is fully machine washable!

For those of us who mix running with cycling, the BOA Fit System isn’t exactly groundbreaking—it’s been the gold standard for years due to its quick adjustability and ultra-secure lockdown. Yet running shoes featuring BOA are still surprisingly rare.

The Under Armour SlipSpeed Mega is one of the few options available—and likely the most budget-friendly. That lower price reflects a single front BOA instead of the usual dual-side setup, but this one delivers an impressively snug, lightning-fast lockdown. In our view, it does the job brilliantly, providing a dialed-in fit in seconds. We love it.

Another standout feature of the SlipSpeed Mega (hence the name) is its convertible heel. This rare-and-versatile design allows for two distinct ways to wear the shoe, making it more adaptable than most.

The first is as a standard running shoe—just slide your foot in and enjoy the structured heel support for a secure, comfortable fit. But there’s an alternative. The collapsible heel transforms the SlipSpeed Mega into a recovery shoe—simply step on the back, and it shifts into an easy-on, relaxed mode, perfect for short walks, or relaxing at home.