Altra Mont Blanc Carbon Review: The SOAR Collaboration Trail Shoe Tested

Introduction

When a shoe brand teams up with a high-end apparel label and bolts a carbon plate into a trail shoe, expectations get complicated. That is exactly what has happened with the Altra Mont Blanc Carbon, a collaboration between Altra and UK-based performance running brand SOAR. We spent a 7.3 mile evening test run in the shoe and in the matching SOAR Trail Race kit to see whether the carbon version earns its place over the standard Mont Blanc line.

The short version: the fit issues that plagued the original Mont Blanc appear to be solved, the midsole remains comfortable and nimble, and the shorts are genuinely excellent. But the carbon plate is harder to justify, and there may be a more affordable shoe in this family that is simply more fun to run in.

The SOAR x Altra Mont Blanc Carbon: Key Specs

The Mont Blanc Carbon is a carbon-plated trail shoe with the premium pricing you would expect from that category. In the UK it retails for £220. In a UK 9.5, our pair tipped the scales at 285g, which is refreshing after a run of heavy trail shoes and keeps the shoe comfortably under 300g.

True to Altra form, it is a zero-drop shoe with identical stack height under the heel and forefoot, at 29mm each. The brand’s signature wide, roomy toe box is present too, and sizing runs true to size with the right length in the toe box.

On launch, SOAR also released a matching running apparel collection, and we tested the SOAR Trail Race top and Trail Race shorts alongside the shoe. SOAR kit is expensive, but the fit and quality have historically impressed.

Upper and Construction

Altra has used two different engineered fabrics in the upper. The front half wraps the toe box in a soft, breathable knit, while the back half uses a largely transparent ripstop material with numerous overlays stitched on for structure and durability. A further overlay sits across the midfoot stitching for extra reinforcement.

The tongue is gusseted into the upper, which is the preferred setup for trail shoes, and although it is thin, Altra has added zonal padding down the centre where the laces pull tight. That padding makes a real difference to comfort across the top of the foot.

Additional overlays wrap the toe box, though upfront protection remains limited because the toe is still fairly soft. At the back there is a Velcro gaiter attachment and a handy heel tab for easier on-and-off. The collaboration shows in the colourway: two different iridescent tones on either side of the shoe with SOAR detailing at the heel.

Midsole and Outsole

The midsole uses Altra’s dual compound setup: a rim of Ego Max foam surrounding a core of the performance-focused Ego Pro foam. The standard Mont Blanc’s midsole was one of its standout features, balancing comfort, performance, and ground feel, so the hope was that a carbon plate would not upset that balance.

In practice, the shoe remains surprisingly flexible for a plated trail shoe, but the plate seems to add a touch of firmness and reduce some of the plush cushioned feel. Underfoot, there is a sticky Vibram Megagrip outsole in the lightweight “Litebase” variant, which keeps Megagrip’s grippy properties at a fraction of the weight.

One thing to note: lug depth is shallow at just 3.5mm. This is not a shoe built for wet, muddy UK winters, and a 4 to 4.5mm lug would have made it a more versatile trail shoe overall.

How It Ran: 7.3 Miles at Pace

Fit was the headline. The original Mont Blanc frustrated many runners with heel lift, and that was completely absent here. The upper delivered a secure lockdown around the midfoot that held for the entire run, a genuinely solid hold in the heel, and comfort across the top of the foot. It really is a night-and-day difference compared with the original shoe.

The dual compound midsole also performed well, feeling nimble, comfortable, and lightweight across varied terrain, with a good level of underfoot protection on rockier trail sections. Here is the catch, though: we did not feel much benefit from the carbon fibre plate itself.

Comparing side by side with the Altra Mont Blanc Speed at home, the Speed felt plusher, softer underfoot, a bit livelier, and frankly more fun to run in. The plate seems to have traded away some of that cushioned, responsive character for a firmer ride without delivering an obvious performance return.

SOAR Trail Race Tee: Light but Clingy

The Trail Race Tee is super light and breathable with a clean overall look, and it was comfortable to run in. However, on a muggy evening at a hard pace, once the sweat really built up the material turned noticeably clingy, more so than other SOAR technical tees we have run in. It is a good shirt, but heavy sweaters should be aware of that trade-off.

SOAR Trail Race Shorts: The Standout Kit Piece

The Trail Race Shorts were brilliant. They fit like a compression short, feel great to run in, and the storage is generous: a stuff pocket on each side of the waistband, a large front pocket that comfortably fits a phone, a pole carrying system on the back, and a good-size secure zip pocket at the rear. Rubber grippers on the legs also proved perfect for getting hands on quads while climbing steep hills.

The catch is the price, which sits at roughly £230. That is very expensive for a pair of shorts, so you need to be genuinely invested in SOAR kit or obsessed with clothing performance to bite. If you are, they deliver.

Buying Advice: Carbon or Speed?

If you are choosing between the two shoes, the Mont Blanc Speed is the safer pick for most runners. It offers a more comfortable and responsive midsole, a more playful ride, and comes in at £55 less than the carbon version. Found at £98 online, the Speed looks like a genuine bargain. Choose the Mont Blanc Carbon only if you specifically want the collaboration colourway or the plated ride, and be prepared to pay £220 for it.

As for the SOAR apparel, the shorts are worth a look if the budget stretches, while the tee is best suited to runners who prioritize weight and breathability over all-sweat-session comfort.

Conclusion

The SOAR x Altra Mont Blanc Carbon fixes the fit problem that let the original down, delivering secure heel hold and midfoot lockdown over a comfortable, lightweight dual compound midsole. But the carbon plate adds cost and firmness without a clear payoff, and the Mont Blanc Speed remains the livelier, more affordable shoe in the family. Combined with the excellent but pricey SOAR Trail Race shorts and a capable but clingy tee, this is a collection best bought piece by piece, with a clear idea of what each piece actually earns.