C1
Road Running
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- Dual-layer midsole design: top layer CircleCELL foam delivers uncompromised performance, crafted from sustainable materials, while the rubberized EVA bottom layer provides support and stability.
- TUNEDFIT Dual Lacing System for separate lace adjustment.
- Wider base and higher sidewalls enhance stability during long runs.
Men's
| USA | 7 | 7.5 | 8 | 8.5 | 9 | 9.5 | 10 | 10.5 | 11 | 11.5 | 12 | 12.5 | 13 | 14 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| EUR | 40 | 40.5 | 41 | 42 | 42.5 | 43 | 44 | 44.5 | 45 | 46 | 47 | 47.5 | 48 | 49 |
| UK | 6 | 6.5 | 7 | 7.5 | 8 | 8.5 | 9 | 9.5 | 10 | 10.5 | 11 | 11.5 | 12 | 13 |
| CM SIZE | 25 | 25.5 | 26 | 26.5 | 27 | 27.5 | 28 | 28.5 | 29 | 29.5 | 30 | 30.5 | 31 | 32 |
Women's
| USA | 5 | 5.5 | 6 | 6.5 | 7 | 7.5 | 8 | 8.5 | 9 | 9.5 | 10 | 10.5 | 11 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| EUR | 35.5 | 36 | 36.5 | 37.5 | 38 | 38.5 | 39 | 40 | 40.5 | 41 | 42 | 42.5 | 43 |
| UK | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 | 7 | 7.5 | 8 | 8.5 | 9 |
| CM SIZE | 22 | 22.5 | 23 | 23.5 | 24 | 24.5 | 25 | 25.5 | 26 | 26.5 | 27 | 27.5 | 28 |
Drag horizontally to see more
Size Measuring Guide
A perfect fit for your ultra-marathon running shoes is important for comfort and performance. Follow these tips to measure your foot size at home:
General Tips:
- Measure your feet at the end of the day as they're at their largest due to swelling.
- In between sizes? One foot is bigger than the other? Take the larger size.
- It's best to measure every year. Your size could change over time.
What You'll Need:
- A piece of paper larger than your foot,
- A pen or pencil,
- A ruler or measuring tape,
- Socks of the thickness you'll wear with the shoes.
Steps:
- Stand on the paper in the socks you'll wear with the shoes.
- Use the pen or pencil to mark the end of your longest toe and the back of your heel. It's important to measure both feet as their size can vary.
- Match your measurements to our size chart to find the best fit. If you're between sizes, we suggest choosing the larger size for better comfort.
Men's
| USA | 7 | 7.5 | 8 | 8.5 | 9 | 9.5 | 10 | 10.5 | 11 | 11.5 | 12 | 12.5 | 13 | 14 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| EUR | 40 | 40.5 | 41 | 42 | 42.5 | 43 | 44 | 44.5 | 45 | 46 | 47 | 47.5 | 48 | 49 |
| UK | 6 | 6.5 | 7 | 7.5 | 8 | 8.5 | 9 | 9.5 | 10 | 10.5 | 11 | 11.5 | 12 | 13 |
| CM SIZE | 25 | 25.5 | 26 | 26.5 | 27 | 27.5 | 28 | 28.5 | 29 | 29.5 | 30 | 30.5 | 31 | 32 |
Women's
| USA | 5 | 5.5 | 6 | 6.5 | 7 | 7.5 | 8 | 8.5 | 9 | 9.5 | 10 | 10.5 | 11 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| EUR | 35.5 | 36 | 36.5 | 37.5 | 38 | 38.5 | 39 | 40 | 40.5 | 41 | 42 | 42.5 | 43 |
| UK | 3 | 3.5 | 4 | 4.5 | 5 | 5.5 | 6 | 6.5 | 7 | 7.5 | 8 | 8.5 | 9 |
| CM SIZE | 22 | 22.5 | 23 | 23.5 | 24 | 24.5 | 25 | 25.5 | 26 | 26.5 | 27 | 27.5 | 28 |
Drag horizontally to see more
Size Measuring Guide
A perfect fit for your ultra-marathon running shoes is important for comfort and performance. Follow these tips to measure your foot size at home:
General Tips:
- Measure your feet at the end of the day as they're at their largest due to swelling.
- In between sizes? One foot is bigger than the other? Take the larger size.
- It's best to measure every year. Your size could change over time.
What You'll Need:
- A piece of paper larger than your foot,
- A pen or pencil,
- A ruler or measuring tape,
- Socks of the thickness you'll wear with the shoes.
Steps:
- Stand on the paper in the socks you'll wear with the shoes.
- Use the pen or pencil to mark the end of your longest toe and the back of your heel. It's important to measure both feet as their size can vary.
- Match your measurements to our size chart to find the best fit. If you're between sizes, we suggest choosing the larger size for better comfort.
Bonne to do it.
Matthieu Bonne is a professional record breaker. From swimming to cycling to running, he’s made endurance his superpower – he even has the record for the most basketball free-throws in 24 hours. When he’s targeting a running record, like the 48-hour record he broke in 2025, Matthieu retreats to Kenya, where the altitude and simple life make for productive training. Known for his incredible mileage, Matthieu’s schedule often calls for back-to-back days of 100 km – precisely the kind of extreme training where the C1 excels.
Featured
The C1 features a dual layer midsole, utilizing a generous layer of our sustainable CircleCELL foam above a rubberized EVA bottom layer that provides the stability you need to go beyond. CircleCELL is the same supercritical foam used in our award-winning H1, delivering energy return on par with PEBA-based foams, while providing double PEBA’s running lifespan.
Despite its wide, stable stance and dual-layer midsole, the C1 comes in at a feathery 9.4 oz / 267 g (US M9), because long distance performance shouldn’t weigh you down. Featuring a 42 mm stack height and 6 mm drop, the C1 is optimized to let you push your limits of speed and distance in training, so that race day comes easy.
The TUNEDFIT Dual Lacing System offers separately customizable fit for the forefoot and midfoot. Because we know that in the ultrarunner’s pursuit of distance, feet can swell and change shape, and having a shoe that can adapt to those changes on the fly can be the difference between minor discomfort and injury. With TUNEDFIT you can enjoy the ride and channel your focus to the miles ahead.
Gallery
Compare our models
The super trainer built for ultra distances.
Long-distance runs, multi-day runs, recovery runs, tempo runs
9.4 oz / 267 g
6 mm
(Heel 42 mm, Forefoot 36 mm)
Wide toe box
CircleCELL™ + Rubberized EVA
TUNEDFIT™ Dual Lacing System
Jacquard
Our record-breaking race-day shoe loved by ultrarunners.
Long-distance / multi-day road races
8.5 oz / 240 g
8 mm
(Heel 35 mm, Forefoot 27 mm)
Wide toe box
LightCELL™ base + ZeroSag™ inserts
TUNEDFIT™ Dual Lacing System
Double-layered jacquard, 40% recycled polyester
Our record-breaking race-day shoe loved by ultrarunners.
Long-distance / multi-day road races
8.5 oz / 240 g
8 mm
(Heel 35 mm, Forefoot 27 mm)
Wide toe box
LightCELL™ base + ZeroSag™ inserts
TUNEDFIT™ Dual Lacing System
Double-layered jacquard, 40% recycled polyester
A stability shoe powered by our groundbreaking support solution.
Neutral / overpronation, everyday runs, walking
9.9 oz / 280 g
10 mm
(Heel 37 mm, Forefoot 27 mm)
Wide toe box
LightCELL™ base + 3D Archrail™ structure
Traditional lacing
Circular knit
A versatile daily trainer for stacking up the miles in comfort.
Long-distance training
9.35 oz / 265 g
10 mm
(Heel 36 mm, Forefoot 26 mm)
Standard
LightCELL™ base + ZeroSag™ insert
Traditional lacing
Jacquard engineered mesh, 100% recycled yarn