Crankbrothers Stamp Boa- Unisex Review

Crankbrothers entered the mountain bike shoe market in 2021 with the introduction of their Stamp and Mallet shoes. The Stamp Flat line of shoes features three different versions of the same shoe: Stamp Lace, Stamp Speed Lace, and the Stamp Boa (tested). The Stamp Boa features a Boa lacing system, mesh panels for breathability, and Match Compound MC2 on the soles with a tread pattern optimized for the Crankbrothers Stamp pedal. Despite being optimized for their Stamp pedals, Crankbrothers states the sole is “is designed to work flawlessly with any flat pedal.”

The Boa lacing system worked flawlessly, and our testers enjoyed the ability to make on-the-fly adjustments, especially on long rides. We were also impressed by the shoes' heel cup and silicone heel dots which kept our heels in place even on steep and technical out-of-saddle climbs. The shoe has excellent midsole absorption, which smooths out the terrain and dampens trail vibrations. However, our testers use Chromag Scarab pedals and had difficulty maintaining a connection between the shoes' sole and the pedal, despite trying different fork settings and foot techniques. Our foot frequently bounced and slipped off the pedal both on technical climbs and descents, leaving us frustrated and underwhelmed. In reading other reviews of the shoe, we found other testers to experience similar issues with other pedal brands.

Performance Comparison

Grip

Crankbrothers has designed their shoes to work optimally with their pedals, and the Stamp is made to work with the Stamp pedals which are available in both small and large sizes. The sole is Match Compound MC2 and the sole's tread pattern matches that of their pedal's pin placement. During our testing, we found the Match Compound sole is not as grippy or sticky as other shoes we tested. We had difficulty with the interface between our Chromag Scarab pedals and the shoe's sole resulting in our feet bouncing and slipping on the pedal, especially on technical terrain.

Crankbrothers states that the shoes' sole is designed to work with any flat pedal, and after experiencing pedal slips on numerous rides, we decided to ride with different shoes on each foot to see if we had the same experience with other brands. When we tried this test, the Stamp shoe slipped much more on the pedal compared to other brands. We also tried a 360 pedal rotation test, going toe down heel down, and found it more difficult to maintain contact with the Chromag pedals during this test as well. On hike-a-bikes we found the sole traction to be so-so, especially on sand-covered slick rock where we had more slipping compared to other shoes tested.

Riders using Crankbrothers pedals may have a different experience with the shoes' grip, however, those using other pedal brands may want to look at other options.

Comfort and Protection

The Stamp Boa uses a Boa lacing system that works flawlessly and allows for quick adjustments and we appreciate not having to tuck away laces into elastic bands. We were able to coast with our foot in the noon position and make micro-adjustments to the shoes fit on rides and a large velcro strap helps to keep things nice and snug, providing a good fit.

Like many of the newer shoe models we tested, we would call the shoes fit medium, neither voluminous nor narrow. Our tester wears an 8.5 women's shoe and has a slightly wide forefoot. Using Crankbrothers sizing chart, an 8.5 women's equates to a EU39.5/US7 which fit comfortably, with no extra slop. Those with extra wide feet may find the toe box a tad narrow.

A highly padded tongue and heel and a TPU reinforced toe box offer enough protection from the trail for most riding, and would even provide enough protection for enduro racing, but we would want a little more protection for true downhill riding. The TPU reinforced toe box provides ample protection from rock strikes. While we appreciate the highly padded tongue, especially with the Boa lacing, we did find it hit the front of our ankle. While this was not uncomfortable, it was noticeable.

The mesh panels on the midfoot tend to bunch and flex over the course of a ride, especially as the shoes broke in, to the point of being visually noticeable to other riders. This may be due to our foot shape and volume and those with a wider midfoot or larger volume foot may not experience this bunching.

One issue our shoes have is different sized footbeds with over a 3/4" difference between left and right. The right insole is 9.5" long and the left insole is 10 3/8" long. The left insole is too long causing it to bunch up in the toe box and the right too short leaving a 1/4" gap at the toe. Over time the bunching in the left became less noticeable, but we expect the insole to be appropriately cut for the shoes' size. We assume this was just a quality control oversight, but feel it is notable nonetheless.

Rigidity and Power Transfer

The Stamp Boa does a great job at keeping the heel in place, especially on climbs. The combination of the velcro strap and heel cup with silicone dots prevents heel lift. Our testers prefer a shoe that absorbs bumps from the trail, as our feet have become uncomfortably sore in the past from flexy shoes. The Stamp's midsole and shank are stiff and absorb trail vibrations very, very well, which is very evident on loose, chunky descents and one of the shoe's best features.

On flat terrain, the shoe's stiffness is noticeable, making it easy to push into the pedals for efficient power transfer. However, on technical terrain, it became hard to separate the shoes' stiffness and power transfer from the sole's grip because of the difficulty we experienced maintaining a connection to the pedal. Again, those using Crankbrothers pedals may have a different experience with this.

Breathability

Many flat pedal shoes do not breathe incredibly well, in part due to their design and construction. Overall, we were pleased to find that the Stamp Boa breathes relatively well thanks to a perforated tongue and mesh panels just behind the toes and midfoot. These panels allow adequate airflow into the foot, and our feet never felt overly hot or sweaty.

We did notice, as did our friends, that the mesh side panels flex quite a bit on the pedal and become misshapen while riding. This creates a gap between the rider's foot and the shoe, which is slightly annoying, but not uncomfortable.

Durability

The synthetic upper, TPU reinforced toebox, and MC2 rubber soles held up very well during our testing, which occurred mostly in sandy and rocky desert conditions. The shoe's Boa lace eyelets are tucked away behind the uppers which adds a layer of protection to the laces. Dirt and mud cake on the shoe's uppers without creeping into the inside the shoe.

Despite not being waterproof, the Stamp does a great job at keeping the foot dry. The Boa, velcro, and padded tongue create a snug fit, which repels dirt and moisture. Even in the rain, our feet stayed relatively dry and the shoes were dry the next day, even with being in a below-freezing garage overnight.

The Stamp's soles remain relatively free of pin scars after our testing, however, on the left sole, there are a few small chunks of rubber missing. This makes us question how well the shoe's soles will hold up over a season of heavy use.

Weight

The Stamp Boa weighs 667-grams for a size EU39.5/US7, which is in line with many other shoes that we have tested with comparable protection.

Value

The Crankbrothers Stamp Boa is the most expensive flat shoe in our testing, which one may expect because of the Boa lacing system. However, the pedal interface with non-Crankbrothers pedals is less than stellar during our testing and we have some concerns about the quality of the shoes due to different sized footbeds and pin scars. Overall, we feel there are better options available which also happen to have lower price points.

Conclusion