Verdict from 8.9 hours of research from the internet

11 reasons to buy

  • Most of the reviewers noted that the All Out Crush Tough Mudder is very comfortable.
  • Drainage ports at the sides and in the front make water drainage excellent.
  • The grip is superb for trail running, obstacle races, and shines in the mud.
  • Some runners really loved the long-distance running capability of this shoe.
  • A very supportive ride for obstacle racing is achieved by Merrell in the All Out Crush Mudder, according to several comments.
  • The outsole lugs shake off mud very well.
  • There are 4 color options.
  • A handful appreciated how easy it is to wash the shoe.
  • The price is a bargain, based on several reviewers.
  • It is rather light without losing the support needed for tough obstacles or mud runs.
  • Several runners appreciated the shoe’s breathability despite the water-resistant upper.

5 reasons not to buy

  • More than a few mentioned that they needed a break-in period for this shoe.
  • The laces often come undone, based on the observations of a small handful.
  • A few said that it feels a bit small.
  • On hardpacked trails or rocky paths, the aggressive 5mm lugs caused some instability while the slightly firm cushioning became very hard, according to a few expert reviewers.
  • Some runners were disappointed that it just felt too narrow for their feet.

Bottom line

Merrell’s sponsorship of the Tough Mudder, has led it to create a running shoe that can live up to this tough name. In the All Out Crush Tough Mudder, people who love to wrestle mud as part of their favorite pastime should get a very supportive, well-cushioned, and stable ride. The shoe, when used solely for trail running, works best in soft, slippery, or wet grounds. It has more than enough decent underfoot cushioning without taking away superb ground feedback. To top it all, the price makes it a mouth-watering prospect for the trail runner or the obstacle racer.

Tip: see the best running shoes.

Expert reviews:

User reviews:

  • The All Out Crush Tough Mudder comes up with the best obstacle racing features that Merrell can create with the limited time they have. Without a doubt, the new 5mm lug configuration gives the shoe the kind of performance that makes it worthy to feature the Tough Mudder insignia in the upper.
  • The lugs provide a versatile grip on a multitude of surfaces in the most slippery conditions. Since the shoe is designed for travails in muddy conditions, the lugs prevent mud from accumulating and consequently weighing down the user.
  • The upper is waterproof and has drainage ports to efficiently shed water. For simple trail running, the waterproof protection makes it an all-weather friend in crushing the trails. As soon as the user takes the plunge into the water, the drainage ports quickly remove water from the shoe.
  • A sturdier, but lighter rubberized toe cap adds another element of protection in this shoe. It prevents the toes from getting bruised without taking much space in the toe box.
  • Finally, adequate reflective materials in the upper make it a suitable option for night-time or low-visibility running.

The fit of the Merrell All Out Crush Tough Mudder gives runners excellent hold and support that are not restrictive. There is sufficient space in the toe box for the toes to comfortably splay. It is designed for those with regular foot dimensions. The length runs true to size.

Merrell’s proprietary M Select rubber dominates the outsole. It is a proven compound in delivering awesome traction, even in wet conditions. This material is also used in the outsole of the All Out Crush Tough Mudder 2

Magnifying the effect of the M Select is the Pinwheel type of 5mm lug configuration. The lugs have adequate size and depth give the runners confidence in tackling obstacle courses or running on rough and rugged terrains when using the All Out Crush Tough Mudder.

A very simple midsole consisting of the Unifly foam runs the full length of the shoe. It has more cushioning and responsiveness than regular molded EVA. Because the foam covers the entire midsole, the transitions from landing to take-off should also be enhanced. Between the midsole and the outsole is a thin piece of TPU film that shields the foot from sharp objects.

A very breathable and waterproof upper covers almost the whole shoe. While the mesh is quite soft, the thin but abrasion-resistant TPU overlays add optimal support and midfoot hold. The tongue is a bit thick while the ankle collar is lightly-padded. A heel loop makes shoe entry and exit easier and more convenient. Merrell placed the Tough Mudder logo near the heel side on the lateral side of this shoe. Giving it more versatility are the reflective materials that make low-visibility activities doable. The M Select technology in the interior provides anti-microbial and anti-odor properties.

Size and fit

True to size based on 54 user votes
Small (39%)
True to size (61%)
Large (0%)
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Same sizing as Merrell All Out Crush Tough Mudder 2.

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How All Out Crush Tough Mudder compares

This shoe: 88
All shoes average: 85
58 99
This shoe: $100
All shoes average: $130
$60 $250
This shoe: 8oz
All shoes average: 10.4oz
5oz 24oz
Jens Jakob Andersen
Jens Jakob Andersen

Jens Jakob is a fan of short distances with a 5K PR at 15:58 minutes. Based on 35 million race results, he's among the fastest 0.2% runners. Jens Jakob previously owned a running store, when he was also a competitive runner. His work is regularly featured in The New York Times, Washington Post, BBC and the likes as well as peer-reviewed journals. Finally, he has been a guest on +30 podcasts on running.