Our verdict

The Salomon X Ultra 4 Mid GTX is a waterproof hiking boot that feels lightweight and supportive and looks and performs like it’s from the 21st century. I love the mixture of grip and waterproofing that makes it an all-weather boot.


  • The boot of choice for multi-day hikes
  • Lightweight
  • Waterproof
  • Excellent grip
  • Supportive midsole
  • Detailed ground feel
  • Great ankle support
  • Protective
  • Perfect lacing system


  • Midsole may be thin for some
  • Very stiff in colder climates

Audience verdict

  • Top 20% most popular hiking boots

Salomon X Ultra 4 Mid GTX review and lab test

The 4th edition of Salomon’s X Ultra line of hiking shoes has kept a lot of features from previous versions, with a couple of noticeable differences. 

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For a mid-height Gore-Tex hiking boot, the X Ultra 4 is insanely lightweight. Aside from this, it’s a brilliant boot, as I expect from a name like Salomon. 

Who the hiking shoe is for

The Salomon X Ultra 4 is a perfect shoe for longer, multi-day hikes with ankle support to help you carry the weight needed for these trips. Thanks to its lightweight construction, more customizable lacing, and waterproofing, this is a great option for long distances where your feet’s comfort is of the utmost importance.

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Who the Salomon X Ultra 4 Mid GTX is not for

There’s probably a better option out there for you if: 

The Salomon X Ultra 4 Mid GTX can take you further

Coming in at 14.5oz (412g) in US size 10, the X Ultra 4 Mid GTX is super lightweight, which is incredibly welcome in any long-distance hiking boot. The energy saved over tens of thousands of footsteps trumps most other weight factors on trails. 


The X Ultra 4 Mid GTX runs a little large, but I would recommend going with your regular size if you prefer thick hiking socks. 

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A midsole that’s sort of there

To get a boot this lightweight there was always going to be a bit of a tradeoff in the midsole. For those who love ground feel, this may actually be a pro. With a heel stack height of 31.5mm there’s actually quite a bit of material underfoot. 

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Where this becomes a concern for some is in the 54HA Durometer, which is quite stiff. I’m guessing that the TPU “chassis” that is used for support makes it even more firm underfoot. 

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I personally didn’t mind this so much, and you can replace the insoles with something a bit more padded if you want, which is always a good idea with any long distance hiking shoe anyway. 

The Salomon X Ultra 4 Mid GTX has some flex issues

The X Ultra 4 Mid is flexible at normal temperatures, scoring 27.9N in our flex test (avg. 37.4), this allows for lots of contact with the ground and an instantly broken-in feel. 

While super comfy, this is also the point of one of my concerns with the boot. I also performed a lab test on the flexibility of boots after placing them in a freezer for 20 minutes. The Salomon X Ultra 4 Mid GTX’s stiffness increased 126% to 63.17N! 

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This is frankly absurd and I had to run a second test just to be sure. The biggest concern here is that if you’re hiking in cold climates, the boot isn’t going to function in an ideal way. 

A welcome respite from quick lacing for some

Salomon’s quick lacing has long been one of my favourite lacing systems on the market. With a self-closing buckle, you can tighten and loosen the shoe in a second. 

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While useful in some circumstances and with certain foot shapes, it’s not ideal for long distance hiking, especially if you have wide feet and you can’t get a perfect, customised fit. The X Ultra 4 Mid GTX uses a more traditional lacing system to provide a firm lock through the ankle. 


This means that you can adjust the forefoot as needed, allowing for some wider feet. This also allows you to leave a bit of space in the ankle if needed (long-hikes result in swollen joints), whilst keeping the forefoot tight. 

The Salomon X Ultra 4 Mid GTX is more supportive than it looks

Although a mid-height boot, the Salomon X Ultra 4 Mid GTX provides more support that I expected. With a high flare in the collar and a TPU “chassis” within the midsole, my ankle was far more secure that usual. 

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I felt confident on rocky terrain with weight, and would probably trust this as much as a full height boot. 

Consistent grip

I’m always confident with Salomon’s outsoles, the Contragrip works wonders in any shoe. 

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There are 41 rubber lugs that are 5.1 mm deep. Alongside a relatively flexible midsole, this offers heaps of traction on any surface, from dry and dusty to wet and boggy. 

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I will say, 41 lugs are quite a lot which can be great, but if you’re often going through super muddy terrain you may want to opt for something with fewer lugs and greater spacing

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I’m a big fan of the heel lug on the outsole as well, which is there to help brake on descents. This is quite a common feature in hiking shoes and boots these days.

Gore-Tex is well implemented in the X Ultra 4 Mid GTX

I’m often one to suggest that our focus on Gore-Tex and waterproofing shoes is a bit mis-led. More often than not a hiking shoe is better without Gore-Tex but with lots of breathability to allow them to dry out. 

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Being targeted at longer distances and multi-day hikes however, I really like the Gore-Tex in the X Ultra 4 Mid. The waterproofing works when submerged for over a minute and the gusseted tongue and higher ankle collar help keep water overflowing. 

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I would always recommend a pair of gaiters to stop anything rolling down your legs and into the boot, but aside from that, the Gore-Tex gets huge tick from me. 


The Salomon X Ultra 4 Mid GTX is a super interesting hiking boot. It has the weight of a hiking shoe but the protection, grip and waterproofing of a serious boot. Perfect in many conditions this is a go-to boot for most hikes. Definitely reconsider if you’re looking to do some winter walking, as the inconsistent flex is a problem for me.

Complete lab-specs overview 

  Salomon X Ultra 4 Mid GTX
Whole shoe
Weight (g) 412g
Drop (mm)


Flexibility of the shoe (N)


Flexibility of the shoe (Freezer 20 min) (N) 63.2
Flexibility of the shoe (% of change) 126.1
Lace slip test with the knot (N) 36.3
Longitudinal flexibility (1-5 scale, 5 being the stiffest) 4.0
Torsional flexibility (1-5 scale, 5 being the stiffest) 2.0
Thickness - Tongue (mm) 17.09
Width Upper - Forefoot (mm) 98.67
Width Upper - Heel (mm)


Lace Stretch (1-5 scale, 5 being the most stretchy) 2.0
Flexibility of the heel counter (1-5 scale, 5 being the stiffest) 3.0
Thickness of Heel Counter (mm) 12.99
Toe Guard Yes
Durometer Toe Guard (Room temperature) (HA) 87.5
Tongue: gusset type Full
Heel: pull tab Yes
Width Midsole - Forefoot (mm) 106.6
Width Midsole - Heel (mm) 84.4
Stack - Forefoot with insole (mm) 20.5
Stack - Heel with insole (mm) 31.5
Durometer Midsole Heel (Room temperature) (HA) 54
Durometer Midsole Heel (Freezer) (HA) 56
Outsole thickness (Heel) (mm) 9.7
Lugs Depth (mm) 5.2
Lugs (Amount) 41
Durometer Outsole Heel (Room temperature) (HC) 82.0
Insole Heel Thickness (mm) 7.65
Insole: removable Yes