Salomon S/Lab Ultra 3 Review

Most popular shoe models are updated every year or every other year, with the goal of continual refinement toward the ever-illusive goal of the perfect trail running shoe. Of course, with every update comes an equal risk that the masses will feel the shoe has worsened. Luckily, with the third iteration of the S/Lab Ultra, Salomon has used restraint where it was needed and kept all the very best elements of what was already the highest-rated shoe in our review. They also added some improvements that only make it better. In version 2, released in spring 2023, the updated upper includes Matryx fiber. While it's claimed to be 10% lighter, we found it closer to around 5%. Regardless, we found this material to be more breathable while providing the same comfort and security we've come to expect and love.

For those unfamiliar with this shoe, expect a very protective feel underfoot, with ample firm cushioning to keep your feet feeling fresh when you are deep into an ultra, but without a lot of spring and give. The upper fits like a sock; while this is a commonly applied metaphor, in this case, it is true. There are no edges to the tongue — the interior liner wraps around the foot with no interruptions. Like most Salomon shoes, this one has a Kevlar quick lace system paired with a lace garage to hold everything tight and keep the foot comfortably secure. Previously this lace storage area was difficult to stow. The new updated Matryx upper on V2 has relaxed the fit, making it easier to “tie” the laces and stow them away. The shoe only comes in one color, a dark and subdued plum purple with bright red accents, and has a look that veers drastically away from the very bright and flashy colorways of many trail running shoes. There is no wide version available on this unisex shoe, and it is not available with a Gore-tex liner.

Performance Comparison

Foot Protection

The polyurethane (PU) foam compound found in the midsole of the S/Lab Ultra 3, which Salomon calls “high rebound,” is one of our favorites because it very effectively protects the bottom of the foot from sharp objects. This feature allows you to run at top speed, or even just sloppily downhill, without worrying that you'll hurt your feet by stepping on something sharp. At the same time, this foam is not spongy or squishy like many others with EVA, which means it won't break down as quickly, lose shock absorption, or wear unevenly. The protection offered by this midsole lasts.

While the S/Lab is easily one of the most protective shoes underfoot, this model takes a small step back in terms of protecting the top of the foot. Gone are the thick rubberized overlays and protective wings — the upper is now a more standard tight-woven mesh with subtle film overlays adding substance and a little bit of durability to the highest wear areas such as crease points. The toe bumper is semi-rigid but not a hard plastic shell. If you often encounter thick underbrush on your runs, we recommend adding gaiters.

Traction

The traction on this shoe remains the same as previous versions and falls near the middle of the pack. It features Salomon's Contagrip MA rubber, which we have found to be very sticky and well-suited to all types of terrain when still fresh. However, this relatively soft rubber will wear down fairly quickly if you wear these shoes often on hard surfaces, such as doing a lot of scrambling (which we like to do on our runs.) These shoes are excellent on rocks and other hard surfaces but may wear out quicker if that is where you take them every day. Unfortunately, soft rubber is excellent at providing traction but doesn't last nearly as long.

The lugs are a tight arrangement of 3.5mm deep diamond shapes scattered all over the sole. Traction will vary from user to user on this model as it's very dependent on body position with a shoe this aggressive. Small lug patterns allow you to use your body to apply pressure instead of making the shoe overcompensate. This overcompensation is fine on easy trails or when moving slowly. But, having large protruding lugs on technical terrain when moving fast is a recipe for disaster. When moving quickly, it's best to have things tight and neat, which is exactly how we'd describe the outsole of this shoe.

Sensitivity

Not surprisingly, given the energy transfer, this shoe is less sensitive than others with more cushioning. Luckily the stack height is still low, providing sensitivity in the ankles. And, this shoe fits so well, that sensitivity largely isn't needed. Your foot is so wrapped and connected to the shoe that it feels like your foot. Placements feel so solid that they require less sensitivity. In other shoes, you are often compensating for slop, even if minor.

However, the Ultra 3 is stiff and dense; if you are out for a stroll, they will feel more restrictive. Just like all gear, there are uses for everything, and users that run less consistently or are less experienced could find this model harsh.

Stability

While many shoes with a 9mm heel-toe drop are not among the most stable, this shoe is a very noticeable exception. It leads the pack as one of the most stable shoes in our review. In fact, we find it just as sturdy as some zero drop shoes and have no problem using it on absolutely the gnarliest off-camber or technical terrain. The best attribute of this performance is the unrivaled fit, which holds the foot so snugly that it simply doesn't move or slip, no matter what. This shoe becomes your foot.

At the same time, the landing platform is flat and wide, offering a stiff and firm landing surface. The S/Lab is not a shoe that bends and morphs to the ground beneath it, but one that retains its shape so you can have the confidence to take off and land from a flat and stable stance every time. If stability is a key point for you, do not be dissuaded by the heel-toe drop, as this shoe feels much lower and more stable than this number would suggest.

Comfort and Fit

We acknowledge that every individual will judge comfort differently, but in our experience (over 100 models of trail running shoes tested), these rank up there with the very best. It all starts with the fit. The shoe's shape is neither overly wide nor overly narrow, effectively pinpointing that happy medium. Compared to other Salomon shoes, which tend to be one of the narrowest brands overall, the S/Lab Ultra 3 is among the widest. We found these to run slightly longer than other brands, but there's no difference between the previous version and the V2 update. However, they are very snug in wrapping the foot to secure it in place. This snugness is apparent as you try to put the shoes on, which is no easy task without a traditional tongue, but this feeling instantly transfers to high performance once you start running.

Some people judge comfort by how plush a shoe feels, and those folks will likely be disappointed here. We consider how our feet feel after 20+ miles, and these shoes reign supreme by this metric. However, there are complaints online about the feeling of the ankle collar biting or rubbing the skin, and we warn you that you must wear socks high enough to cushion against this collar. No-show socks or socks with tabs won't work. While we find them to be of average width, runners with wide feet will likely feel a bit too crunched for long distances as well.

Weight

The Ultra 3 weigh in at 10.64 ounces per shoe in a men's size 10.5, slightly lighter than the previous non-Matryx version. We didn't notice a huge difference even though Salomon claimed almost a 10% reduction. We wonder if this is 10% overall or just 10% within the upper — it's not clear on Salomon's site. Regardless, this shoe's performance is the same, and the breathability has improved, which we always appreciate. We'd argue that this model is slightly less snug than the V1, but we didn't notice any impacts to performance. The material also absorbs less moisture and is stiffer than the previous fabric knit upper. We prefer the updated version, although if you can find the old one on sale, it's hard to recommend one over the other, especially if you are saving a substantial amount of money.

While this weight is a good bit more than the lightest weight options, keep in mind that these shoes are designed to offer the protection and stability needed for ultra races in the most challenging terrain, something that lightweight shoes can't provide. Compared to other models with a similar weight, these are some seriously burly shoes, and so they speak to a high-quality design that keeps weight firmly in check.

Should You Buy the Salomon S/Lab Ultra 3?

The S/Lab Ultra 3 is an amazing shoe. We think it's best for users with a substantial amount of running experience that already have multiple shoes. If you are looking to increase your speed and terrain choices, this could be a good step up — especially if you already have a dedicated softer trainer. If this is your first trail running shoe, we'd recommend something a little softer.

What Other Trail Running Shoes Should You Consider?