Béhoust, France · Saturday, April 18, 2026
Fixed Distance 50 mi
La Diagonale des Yvelines 80km
Race completed
80 km Distance
860 m Climbing
5.3 Grit · Challenging
What the course asks
Climbing rate 11 m / km
Fast & Flat. This course is relatively flat and fast. Ideal for PB attempts.
Time limit 12 hours
9:00 min/km average. Comfortable. Room to walk the climbs and stop at aid. Among the tightest 50 mi cut-offs we track. Measured against 455 races of the same distance. Cut-off calculator →
Field size ~104 Mid-sized. Company early, well spread out by halfway.
DUV results for the 2026 edition (80km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.
Typical conditions, April
Daytime high 15°C
Night low 5°C
Rainfall Mostly dry
Daylight 13 h 49 m of light
Regional 2001-2020 average for April — NASA POWER, grid elevation 116 m. Not a forecast.
The Aid Station
Course-specific beta from the community
This is a fast & flat course. Expect fast, runnable sections where rhythm is key.
With trail terrain, choose a shoe with moderate cushioning for optimal performance.
Gear for this race
Chosen for 80 km of trail with 860 m of ascent.
- Trail Running Shoes80 km of trail — cushioning that is still there in the last quarter.
- Race Nutrition80 km of self-supported fuelling between aid stations.
- Hydration VestsFlask capacity for 80 km, without the bounce.
- HeadlampsA 12 h limit puts you out there after dark.
- GPS WatchesBattery life first — a 80 km day outlasts most full-GPS modes.
Course Notes
départ du château de Béhoust, arrivée à Rochefort-en-Yvelines
Similar races
Other 50 mi trail ultras, closest in distance first.