Merrell MTL Thermo Rogue 4 Mid GTX – 200g Insulated Hiking Boots Review

Merrell’s Thermo Rogue 4 Mid GTX winter boots are insulated with 200g Primaloft Gold insulation and have all the features that veteran winter hikers look for in a cold-weather hiking boot. They are compatible with snowshoes and most winter traction aids from microspikes up to full crampons, they have a well-protected toe box, front gaiter ring, a heel ridge to secure a snowshoe heel strap, a gusseted tongue, and a shallow arch for gaiter compatibility. Merrell has been making quality 200g winter hiking boots for years, and that experience shines through in this pair of boots.

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• Type: Mid-height
• Gender: men’s (women’s also available)
• Insulation: 200g Primaloft Gold Eco Series synthetic insulation, 300g Aerogel inserts in toe box and sole
• Waterproof: Gore-tex
• Material: Ballistic mesh and TPU uppers
• Rock plate: Yes
• Fit: True to size
• Outsole: Vibram Arctic Grip All Terrain
• Weight: 2 lbs 4.4 oz / pair (men’s US 10.5)

The Merrell MTL Thermo Rogue 4 Mid GTX is a very comfortable mid-height hiking boot that feels like a traditional leather hiking boot but is much lighter and has a slightly flared heel. The boots have a low arch that can hold a gaiter strap and modest lugs for traction, given that you’ll probably be using some traction or flotation aid (microspikes, crampons, or snowshoes) with them anyway, for winter hiking.

While they look and feel “normal” make no mistake, they’re outfitted as insulated winter hiking boots with a Gore-tex liner, Primaloft and Aerogel insulation, a rigid toe box, a gusseted bellow tongue, a gaiter ring, and a rear snowshoe strap ridge. With 200g insulation and 300g in the toebox, they’ll keep your feet warm down to about 0-10 degrees (F), providing you’re active and not standing around. I’ve been hiking with them for several weeks now and they’re warm once your feet heat up and reliably waterproof. And, the fit is true to size.

While they do have a flared heel, it’s nowhere as extreme as the Hoka Kaha 2 Frost GTX mids I reviewed recently. In fact, the length and width of these match with my regular winter hiking boots, the calf-high Oboz Bridger 10″ 400g.

When evaluating insulated hiking footwear for winter hiking and snowshoeing, you need to consider your entire winter footwear system, including insulation, traction, and flotation. Chances are you’ve invested a considerable sum in gaiters, microspikes, crampons, and snowshoes…or you will..so you’re going to want footwear that can gracefully interoperate with those components.

Traction Aid and Snowshoe Compatibility

Traction Aids

If you need traction on a winter hike, you’re going to be carrying and using one or more of the following traction aids that are compatible with soft-soled footwear.

• Elastomer anchored spikes like Kahtoola Microspikes or Hillsound Trail Crampons
• Crampons for soft-soled footwear like Kahtoola K10 or KTS crampons, Hillsound Trail Crampon Pros, or a Full Crampon with a flexible leaf spring like the Grivel G10 or Black Diamond Contact Crampons, etc.

How well does the Merrell MTL Thermo Rogue 4 play with the binding systems of these various traction aids?

• Hillsound Trail Crampons: The pair I normally use (with Oboz Bridger 10″ boots) fits fine over the Merrell MTL Thermo Rogue 4. Equally important, the boot’s toe box is rigid enough to withstand the pressure exerted by the elastomer harness and does not collapse.
• Hillsound Trail Crampon Pro. The ratchet-style binding of these crampons works very well with the Merrell MTL Thermo Rogue 4’s flared heel. This would be my preferred traction device with these boots on heavier ice.
• Kahtoola K10 Crampon. The flared sole of the Therm Rogue 4 is compatible with the K10, but not as rock solid as the Hillsound Trail Crampon Pro or the Grivels. Use extra care when strapping down the heel so it is flush with the crampon frame under the sole.
• Grivel G1 Crampon: The flared sole of the Therm Rogue 4 is compatible with the Grivels. The fit is significantly more secure than that of the K10s because the back of the binding is more pliable and taller.

Flotation

The only snowshoes I have on hand are MSR Evo Ascents with traditional 3-strap ski bindings. These tend to work with any boot, including mammoth mountaineering boots, and they work particularly well with the Merrells, which have a rear showshoe ridge to trap a snowshoe strap and prevent it from slipping off.  That said, I don’t anticipate any difficulty with snowshoe bindings from Tubbs, MSR, and Atlas snowshoes since the front half of the Thermo Rogue 4 is a “normal” sized boot and compatible with most snowshoe bindings.

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Recommendation

The Merrell MLT Thermo Rogue 4 GTX Mid is an excellent 200g insulated waterproof winter hiking boot that is compatible with a wide range of winter traction aids despite having a moderately flared sole. These boots are comfortable and have a solid feel even though they’re made with mesh and TPU uppers instead of leather. While they are a pleasure to hike in, I have to wonder if the flared heel adds all that much functionally and what they’d be like with a more traditional heel with vertical sides. Regardless, they’re great boots for non-technical winter hiking in snow or in the mixed conditions of autumn and spring.

To summarize: the Thermo Rogue is compatible with traction devices suspended from an elastomer harness…microspikes or trail crampons. It is also compatible with crampons designed to be used with flexible soles. The most secure of these is the ratchet-style Hillsound Crampon Pro, then the Grivel crampon binding, and the Kahtoola K10 Crampon, which is workable but feels less sure. Snowshoe compatibility is good but needs to be tested further.