The best Trail Running SHOE FOR UTMB: INSIGHTS FROM FLORIAN GRASEL
Few runners know the Ultra-Trail du Mont-Blanc (UTMB) better than Florian Grasel. The Austrian ultra runner has tackled nearly every iconic distance at the event and consistently delivered top performances.
In 2018, he completed the 171 km loop around Mont Blanc in an incredible 23h12min03s, securing 9th place overall. More recently, in 2024, he took on the legendary Petit Trotte à Léon (PTL) — a 300 km team challenge with 25,000 meters of elevation and no aid stations — finishing second after over 110 hours alongside his teammate Thomas Wagner.
According to Florian, UTMB is “the perfect mix of everything a trail runner dreams of: alpine singletrack, steep climbs, long descents that destroy your quads, and runnable sections where, if you still have legs, you can fly.”
So, what does a world-class athlete like Florian look for in the perfect trail running shoe for UTMB?
Understanding the UTMB Terrain: Is It Technical?
Despite its brutal length and elevation, UTMB is considered non-technical, especially compared to other mountain ultras. In recent editions, elites like Kilian Jornet and Jim Walmsley have completed the race in under 20 hours — averaging 7:02 min/km.
Still, the terrain varies:
The dry, steep descent into Courmayeur.
The long traverse to Refuge Bonatti.
Endless switchbacks from Col Ferret.
Slippery, rocky segments near Col du Bonhomme.
As Florian explains: “You don’t need a super-aggressive trail shoe. What you need is a shoe that performs well across all surfaces — one that makes the kilometers easier.”
Why Fit Is Everything – The BOA® Fit System Advantage
Models like the La Sportiva Jackal II BOA®, Altra Timp 5, or Kailas FUGA DU DUAL BOA® integrate the BOA® Fit System, offering precision fit, microadjustabiliy, and enhanced heel hold — all backed by science from the BOA® PerformFit™ Lab in Denver.
Cushioning vs. Reactivity – Finding the Balance
For ultra distances, cushioning is crucial.
“I look for enough cushioning to protect my legs over 100+ kilometers,” Florian explains. “But it still needs to be responsive. You need to find the sweet spot based on your pace and experience.” Each runner’s preference may vary, but protection without sacrificing energy return is key.
Outsole and Grip – Less Mud, More Versatility
UTMB doesn’t typically feature muddy terrain. That’s why Florian avoids soft-ground shoes. Instead, he recommends:
Lugs between 4mm–6mm.
Versatile grip for mixed conditions — from dusty descents to rocky paths.
“Traction is important, but I want a shoe that performs on all the different surfaces UTMB throws at you,” he adds.
Weight – Is Lighter Always Better?
Elite runners often chase the lightest shoes possible — but Florian’s priorities have shifted:
“Years ago, I was obsessed with shaving grams. Now, I care more about fit, grip, and fulfill the needs for the whole day.. I want a shoe that helps me go the distance, not just one that’s light on the scale.”
Florian Grasel’s Shoe Picks by UTMB Race
From personal experience, here’s what Florian recommends for each UTMB race category:
PTL – The most extreme race during UTMB. Last year, Florian used a mix of shoes depending on the day and terrain. He started with the Scarpa Ribelle Run Kalibra, then switched to the La Sportiva Jackal II BOA®. If he had to choose just one pair, he’d go with a prototype he is currently developing for Kailas.
“They are perfect for such an ultra-long adventure.”
UTMB® – To run around Mont Blanc, Florian chooses the new Altra Timp 5 BOA®.
“The shoe that best matches the overall concept of the race for me.”
TDS® – Known as the most technical race at UTMB. That means more protection and an exceptional outsole are essential. Florian has used the La Sportiva Jackal II BOA® in many technical races and wouldn’t hesitate to use them again. “Superb outsole and protection in rocky terrain.”
CCC® / OCC® – Less technical and more runnable terrain. Depending on the runner’s goals and needs, Florian recommends either the Altra Timp 5 BOA® or the Kailas Fuga DU BOA®. “Great combination of cushioning, speed, and grip.”
Last Advice from Florian before choosing which shoe you will use for UTMB “For every race, I keep my ‘vice-versa’ shoes in the drop bag — ready to swap if conditions or my body demand it. Changing into a very different model can be a welcome mental — and muscular — reset.”