20/07/2026
Tron Ultra Endurance 2027
🏔️RACE BRIEFING — TRONFJELL 20 KM / 1700 HM
🎯Overview
The Tronfjell course is a highly demanding mountain route featuring four summits, long
off-trail segments, technical rock sections, steep descents, exposed high-mountain terrain, and
rapid weather changes. Runners must be prepared for heavy climbing, uneven surfaces,
navigation challenges, and sustained physical effort.
Distance: 20 km
Elevation gain: 1700 m
Highest point: Tronfjell — 1666 m
🧭Segment-by-segment briefing
🌲1. Forest trail — 0 to 1.5 km
• Flowing singletrack with roots, moss, and soft ground
• Moderate incline, easy rhythm
• This is the only truly easy part of the entire race
• Hold back — the difficulty increases sharply after this
Terrain: forest trail
⛰️ 2. Off-trail climb → Nordkletten (1084 m) — 1.5 to 2.5 km
A 1 km heavy and steep ascent.
• First half: soft peat, wet and energy-draining
• Second half: loose rocks, uneven and technical
• No trail — choose your own line
• Heart rate spikes, pace drops
Terrain: peat terrain, boulder field
🏞️ 3. Descent from Nordkletten — 2.5 to 3.5 km
A beautiful 1 km mountain trail.
• Firm surface
• Good flow
• Light technicality
• Perfect section to regain rhythm and speed
Terrain: mountain trail
🪨 4. Off-trail climb → Mellomkletten (1195 m) — 3.5 to 4 km
A short but steep 500 m ascent.
• Mix of peat and rocks
• Uneven, heavy, and technical
• No visible trail — pure mountain navigation
🌲5. Descent from Mellomkletten → 854 m — 4 to 6 km
• Flowing mountain trail
• Firm, runnable surface
• Moderate technicality
• A welcome break before the next big climb
🏔️6. Climb from 854 m → 1185 m — 6 to 7.5 km
A 1.5 km grind on a poorly marked trail.
• Lots of peat
• Several bog sections
• Trail is faint and hard to follow
• Uneven, wet, and energy-draining
🪨7. Off-trail traverse → mountain ridge — 7.5 to 9 km
• Heavy terrain, but not steep
• Mix of peat, bog, and loose stones
• No trail — navigation required
• Mentally demanding and physically slow
🏔️ 8. Red-marked trail → Tronfjell summit (1666 m) — 9 to 10.5 km
Two completely different parts:
Part 1 — 500 m
• Steep but runnable
• Firm ground
• Clear red markings
Part 2 — ~1 km
• Brutal terrain
• Large loose rocks
• Highly technical and uneven
• This is the most difficult segment of the entire course
🛣️ 9. Tronfjell → Flattron (1305 m) — 10.5 to 13.5 km
A 3 km downhill on mountain gravel road.
• Easy surface
• Consistent steep gradient
• Fast, but hard on quads and knees
• Fully exposed to wind
Terrain: gravel road
🏞️10. Flattron → technical mountain trail — 13.5 to 14.5 km
• 1 km of nice but technical singletrack
• Good flow, but fatigue makes it tricky
⛰️11. Steep descent — 14.5 to 16 km
A 1.5 km drop from 1300 m to 883 m.
• Very steep
• Uneven surface
• Requires controlled speed
• Heavy load on legs and concentration
🌲12. Final 3.5 km to finish — 16 to 20 km
• Easy gravel roads and forest trails
• Some minor climbs
• Runnable and steady
• A comfortable finish after a brutal course
⚠️Safety & mandatory considerations
• Weather changes rapidly above 1200 m
• Strong winds on the summit are common
• Boulder fields can be slippery when wet
• Bog sections may be deep
• Mobile coverage varies
• Recommended gear: windproof jacket, water, energy, phone, GPS/map
🧠Race strategy
• Don’t push early — the first 1.5 km is deceptive
• Keep a steady effort on steep climbs
• Take your time in rock fields — avoid missteps
• Use the flowing trails to regain pace
• Control your speed on the long downhill from Tron
• Save a bit of energy for the final runnable 3.5 km
🏁Summary
The Tronfjell course is a raw, technical, and highly
varied mountain challenge. It demands strength,
balance, navigation skills, speed control, and mental
resilience. The reward is one of the most iconic
mountain routes in Østerdalen.
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