This Shoe Could Bag the Most FKTs on Earth

In the running world, a fastest known time (FKT) is the ultimate achievement. Setting even one FKT is a remarkable feat. But Merrell is after a next-level claim to fame. By partnering with athletes around the world and tapping into new design innovations, the brand is on a mission to make the MTL Skyfire 2 the running shoe with the most FKTs. It’s a serious challenge; some FKTs depend on the smallest logistical and technical details—down to the weight on the runner’s feet. We tapped professional trail runner, FKT chaser, and Merrell athlete Rachel Tomajczyk and Merrell product designer Drew Engel to learn more about setting FKTs and the shoe designed to get it done.

Outside: What kind of preparation goes into setting an FKT?

Rachel: A lot of research and planning go into prepping for an FKT. Fastestknowntime.com has a map with all the FKT routes around the world. You can see existing FKTs, distance, elevation, and even download the GPX. I usually plug the GPX into Strava and create a route for myself so I can analyze it. That way I can see where the climbs and descents are and know the turns before my attempt. 

Picking out the right equipment is also an important part of planning. Knowing the weather and the route distance and elevation helps me decide what to wear and how much water and nutrition to carry. Some routes are short and sweet, and I don’t need to bring much with me. If I’m out there for over 1.5 hours, I always bring water and gels to fuel. Most importantly, I always go for fast and light footwear, like my MTL Skyfire 2 for an FKT attempt.

Why is the MTL Skyfire 2 the ultimate race-day shoe?

Rachel: Whether I’m running against the clock for an FKT or racing against the best in the world, every second matters. Every ounce weighs me down, and every slip or slide on the trail is another second wasted. The MTL Skyfire 2 is my favorite race-day shoe because they are super light, so I’m not carrying more weight than I need. Plus, they still offer protection from sharp rocks and roots in the trail. 

These shoes are so precise on the trail, and the Vibram Megagrip traction is unreal. I can pinpoint the exact part of the trail I want to land on and not worry about sliding around, even in muddy conditions. They have an amazing draining system too. If I need to cross a stream, the shoes dry out quickly and I don’t have to worry about blisters.

What sets the MTL Skyfire 2 apart from other trail running shoes?

Drew: In the early stages of the design process, the Merrell product team questioned every element of traditional trail shoe architecture. This method allowed us to establish an innovative platform, only including features that were absolutely necessary for performance. The MTL Skyfire 2 is built around a full-length BZM-8 plate. With tuned rigidity and protection underfoot provided by the plate, the shoe no longer needed a rubber outsole as a protective surface. To shed additional weight, the five-millimeter Vibram Megagrip lugs are connected by a thin rubber weblike structure. The visual is quite striking, but functionality and weight savings are the rationale.

Continuing the theme of weight savings, the upper is constructed from a lightweight engineered material, with reinforcements in key areas. This combination of materials creates a precise, breathable, and drainable upper. A bold diagonal stripe across the engineered design is the MTL Skyfire 2 signature, making it unmistakable on the trail. Finally, Merrell removed excess material from the internal construction by reengineering the lining package with a heel pillow surrounded by microfiber. The cumulative result is an extremely lightweight, precise, and nimble trail shoe that challenges the limits of the space.

Rachel: I’ve run in a variety of trail running shoes, and these shoes are built different! They are the lightest, fastest, and most precise shoes I’ve ever run in by far. Other shoes either have great traction but they’re bulky. Others are light but don’t grip the trail well. The MTL Skyfire 2 has the perfect blend of light and quick while still giving me the traction I need on a technical trail. The BZM plate and FloatPro Foam offer protection from rocks and give me some extra bounce when I’m going uphill, so I feel quick and agile the whole race.

How does the lightweight design of the MTL Skyfire 2 maintain the level of stability and protection that record-setting trail runners need?

Drew: The MTL Skyfire 2’s Flexplate is the key to achieving high-performance characteristics while maintaining a light weight. 

This feature allowed the Merrell team to solve for multiple factors with one component. The team chose to construct the plate using BZM-8 because of the material’s ability to maintain high levels of rigidity and durability at a comparatively low weight and thickness. The Flexplate has a series of alternating reinforcement bars and slits in the forefoot that align with the metatarsals of the foot. This geometry provides longitudinal stiffness for forward motion and lateral flex for adaptability on uneven terrain. Additionally, a void in the Flexplate under the heel allows for connection to the cushion during downhill sections, while the vertical heel counter prevents the foot from shifting in the shoe. A two-part, dual-density FloatPro midsole that sandwiches the tech works in tandem with the plate, adding responsive cushion in the forefoot and protective cushion in the heel. The plate stabilizes the platform while allowing for adaptability and protection.

Rachel: Stability is always something I look for in a race shoe. I need stability so I don’t twist my ankle or slide around on a slick trail. Usually the lighter a shoe is, the less stable I feel in it.That’s not the case with the MTL Skyfire 2. This shoe has great traction, so if I’m on a slippery trail, I still have control. The slender fit allows me to be precise with my foot placement; I’m able to step on the exact part of the trail I need to. This precision makes me feel more connected to the ground and trail, so I’m very aware of the trail’s character and all its twists and turns. This awareness and accuracy has saved me from some injuries and wipeouts.

What challenges have you been after lately with the MTL Skyfire 2? And can you give us a sneak peek at what’s next?

Rachel: My very first race in the MTL Skyfire 2 was the World Uphill Running Championships. My team and I brought home the team gold medal. Later that week, we won the team bronze in the Classic Mountain Championships. I think it’s safe to say the MTL Skyfire 2 are some of the fastest shoes in the world!

Since summer and fall are my main racing seasons, I’ve been going after FKTs in the MTL Skyfire 2 this winter. So far, I’ve set 12 FKTs this year! FKTs allow me to blend two things I love—adventure and challenge—by exploring new trails and pushing myself for course records. I’ve set FKTs in my current home state, Arizona, as well as California, Michigan, and Texas. This season, I’m hoping to make the USA World team again, race some of the Golden Trail Series races, and go after an OCC qualifier. I’m excited for this season of racing and all the trails and countries I’ll get to explore with Skyfires on my feet.

Merrell exists to share the simple power of being outside. As the global leader in outdoor active footwear, Merrell is focused on merging performance, styling, and comfort to empower all people to confidently explore the outdoors. Visit Merrell.com or follow us on social @MerrellTestLab.