With over 750 miles (1200 km) of very comfortable trail running, I have now taken a first pair of the S Lab X-Series “road” shoes from box to bin. These miles have been almost exclusively in rocky and rocky technical trail situations including scree, scrambles, water crossings (including rivers), medium mud, snowfields, and precipitous knife-edges. The shoes are still very runnable but they have lost a bit of forefoot cushioning and, in an effort to be proactive about shoe wear-out rather than (regretfully) reactive to some sort of foot issue, I have taken this first pair off-line and started rotating two new pairs. I could continue running in these on shorter runs but I will probably use them for hiking through the summer. Suffice it to say that the X-Series has more than lived up to initial impressions and continues to be a great performer on just about any trail here in the Northern Rocky Mountains.
These shoes have about 760 miles (1225 km) so at US$160/pair that gives a wear value of about US$0.21/mile (US$0.125/km). This is about the same calculated cost per mile as that experienced with the Sense 3 Ultra. 750+ miles (1200+ km) is very good wear in my experience even at the $160 price point.
The X-Series upper is constructed of three primary materials: a thin Lycra in the forefoot back to about the midfoot, a very thin mesh on the outside midfoot area, and a beefy nylon mesh for the remainder around the heel, etc. I initially had concerns about the durability of the Lycra and thin mesh materials, as Salomon in the past have used materials in the S Lab Sense line that did not wear well. Additionally, Salomon markets the X-Series as a “road” shoe with crossover capability to “City Trails” (whatever that means). The wear characteristics of this shoe in the rocky and rocky technical trails that I run was a concern as it relates to durability of the upper. Even after this significant mileage on rocky and rocky technical trails there is no sign of excessive wear (or wear at all) in any of the upper materials with the exception of the tips of the heel counter inside surface.
The heel counter inside surface is the only place, other than the midsole cushioning, in the entire shoe that is showing any kind of wear-out. These wear-through spots do not affect the fit or function of the shoe at this point, but continued degradation will likely become bothersome.
The polymer-fabric overlays/lacing structure exhibit no wear and continue to perform as when new. The overlay fabric/ lacing structure materials are very tough as they experience a lot of strain and abrasion, yet, other than color fade, look new.
The “rocker” geometry has held up well and has, in fact, become more pronounced. I find that I very much like the “rocker” and suspect that this geometry may play a significant role in the high comfort level of the X-Series.
After a few bouts with foot bruising I have committed to retiring a shoe before a worn-out EVA layer leads to some sort of acute or chronic foot issue. I have experienced both and solved the issue with shoe replacement. In the X-Series I am perhaps retiring this pair a bit sooner than I would have in the past, but I am trying to navigate a balance between wear-out and insufficient cushioning. I am erring on the more cushioning side of that balance going forward. A runner with a “tougher” foot might get another couple hundred miles out of these shoes.
Perhaps the most remarkable circumstance with the X-Series is how durable the outsole is. I am a significant supinator and therefore typically see excessive wear on the outside edge of the outsole, particularly at the heel (see my other reviews and updates of the S Lab Sense variants for examples of this type of wear). The X-Series shows almost no wear across the entire surface and clearly the outside heel area is not differentially worn relative to the rest of the outsole. It is hard to believe when looking over the outsole that these shoes have seen 760 miles (1225 km) of use on rocky and rocky technical trails, including scree, scrambles, and many water crossings.
The Salomon S Lab X-Series is the most comfortable trail shoe I have ever used, and my use includes many of the Hoka, Innov8, and Altra offerings. I will note here that I also had initial concerns with how “hot” the X-Series would run as Lycra is well known for not being very breathable. Having run a few times in air temperatures exceeding 85 F (30 C) where surface temperatures were in excess of 100 F (38 C) I can report that the shoes actually run quite cool and certainly on par or better than the Sense. Also the proprioception of the X-Series is outstanding and leads to substantial confidence while running in technical and challenging terrain as well as increased speeds on descents.
How Salomon accomplished all of this with what is billed as a “road” or “hybrid” road/trail shoe I am not certain. I will offer that the combination of a larger outsole area, larger outsole contact area, the dual density EVA construction, (apparently) just enough additional midsole thickness, and light materials has resulted in a very different shoe than the S Lab Sense- one that not only performs in the mountains but also does so with a comfort level much greater than the Sense, particularly on long runs/races. It seems also that there may be some sort of midfoot construction detail that leads to a higher comfort level as one fatigues and begins to transition from a high proportion of forefoot strike to increasing amounts of midfoot and heel striking. All of this is conjecture but the proof is in the taste of the pudding…. and this is very good pudding!
Salomon have (unexpectedly, since the X-Series is supposedly a “road”/”hybrid” shoe) produced a high performance, light-weight trail shoe that provides a high level of long run comfort, superior trail feel, high durability, and all-around performance on mountain terrain. This is a shoe that trail runners should consider even though Salomon bill it as a “road” or “hybrid” road/trail shoe. Highly recommended.
I will be using the S Lab X-Series exclusively for training and racing this season including two 100 km high mountain/large vert races, a four day mountain stage race (with obscene vert), and a high mountain 50 miler. Looking forward to where Salomon takes the X-Series for SS2016.
Note 12 July 2015
It seems that Kilian used the S Lab X-Series for some portion(s) of his 2015 record-breaking performance. Here he is changing shoes at Telluride aid station before climbing 1400 m (4500 feet) up Bear Creek on road, then trail, then snow fields over Oscar’s Pass and then a 950 m (3100 foot) decent into Chapman. Looks like he is changing into the X-Series (with an all black wear layer) from the 2016 Sense (or some new prototype). This is a testament to the versatility of the X-Series, a supposedly “hybrid” road/trail shoe!