STIFFNESS/POWER TRANSFER
This is a very stiff shoe. Bontrager rates it as a 14 out of 14 on their own “Stiffness Index,” and it shows. This was one of the stiffest models we tested out of a group of exceedingly stiff, high-end shoes. Not surprisingly, power transfer out of the Bontrager XXX Mountain Shoe is nearly unmatched. Stomp on the pedals, and the bike immediately leaps forward. Combined with a very stiff upper, there is little to no wasted energy in the transfer of power. The heel of the shoe also features a no slip lining, essentially a larger portion of fabric on the back, that helps keep the foot locked in place, further aiding in power transfer. In short, these were simply one of the best in this category.
FIT/COMFORT
Our testers wanted to like the fit of this shoe, but we consistently had a few quibbles. Firstly, some testers were right in between sizes, and the shoe vacillated between feeling just right and overly roomy. The toe box in particular felt quite large for the size of the shoe – ideal for someone who likes extra room in the toe box or often wears thicker socks. However, on some rides, this led to a sloppy feeling within the shoe. Testers commented on their feet sliding around rather than being locked in place. Additionally, the upper of the shoe is equally as stiff as the sole, which was fantastic for racing days, but became a minor source of discomfort on more leisurely rides. This is definitely a shoe for race day and hard training rides, not recovery days.
CLOSURE SYSTEM
The Bontrager XXX Mountain Shoe features a BOA closure system. In our experience, the BOA system is simply the best and most efficient way to dial in the fit and comfort of a shoe. While the BOA system works quite well on the Bontrager XXX, the lacing pattern is such that the shoes lack some of the fine tuning ability of its peers. The BOA dials are isolated on the mid and upper portion of the shoe, with a Velcro strap at the toe. While this works quite well, when the upper stretched, the compression could become quite even. It is simple enough to reach down and quickly adjust, but other lacing patterns held the fit of the shoe a touch better.
CONSTRUCTION/DURABILITY
These shoes are constructed of high quality materials and feel solid. The sole is built of a stiff carbon, fiberglass composite, while the upper is made of a polyester and nylon blend. The stitching looks top notch and our testers have gotten many miles out of the BOA closure system. There have been reports of issues with the soles coming apart, but we did not experience this ourselves. These shoes are not the best choice for regular hike-a-bike sections, especially over rocks. After all, they are race shoes so walking is not really a design element. However, in normal use and riding conditions, these shoes should last for many years.
BREATHABILITY
The Bontrager XXX Mountain Shoe breathes reasonably well. They are not a particularly airy shoe, but there were very few complaints from testers. There is a single mesh vent in the toe box which helps prevent the shoes from overheating, but the stiff upper is not the most breathable out there. However, the shoes are so light that they don’t really have enough material to trap in moisture and air, so all but those with the hottest of feet should find these shoes comfortable.
THE VERDICT
The Bontrager XXX Mountain shoe is a high-end cross country style shoe that excels at power transfer while maintaining a reasonable amount of comfort. For the right rider under the correct conditions, these shoes could be some of the best out there. Others may find the fit a little finicky, it’s best to find a pair to try out first.
