GPXray
Build your race strategy before race day.
Analyze terrain, simulate realistic pace, and understand where your race is decided.
Build your race strategy before race day.
- → Analyze the terrain
- → Simulate realistic pace
- → Find the decisive spots
🌤️ Race Day Weather Forecast
ITRA (International Trail Running Association) assigns performance scores based on your race results.
🔍 Find your ITRA scoreAdjust based on your climbing and descending ability compared to average. Strong climbers can run uphills; cautious descenders brake more on downhills.
Select what you actually use during races. We'll suggest these in the Fuel column.
Drag & drop a GPX file here or
Load a sample trail to explore the features
Route
ITRA (International Trail Running Association) assigns performance scores based on your race results.
🔍 Find your ITRA scoreAdjust based on your climbing and descending ability. Slide right (cyan) = faster, left (orange) = slower.
Select what you actually use during races. We'll suggest these in the Fuel column.
How do you handle terrain? This personalizes your pace predictions.
Average downhill stress per km (steepness × surface).
Course intensity:
• <50: Easy terrain
• 50-100: Moderate descents
• 100-150: Demanding descents
• >150: Quad-buster!
Pace loss depends on your runner level. - How it works
Based on total elevation gain, gain per km, and longest climb.
• <15 m/km — flat, leave them home
• 15-25 m/km — optional, personal preference
• 25-40 m/km — recommended for climbs
• >40 m/km — strongly recommended -
Approximately every ~45 min at flat terrain or AID stations.
Total carbs = est. finish time × g/h target.
Defaults: beginner 50, intermediate 65, advanced 80, elite 95.
Override under Advanced Options → My Fuel → Carbs (g/h).
Adapts to race time and terrain:
🍫 = Bar (early race, flat terrain)
🍬 = Gummy (mid-race or climbs)
⚡ = Gel (late race, quick energy)
🚰 = Water/refill at AID
⬇️ Dynamic Descent Load → Pace Loss
DDL builds up as you descend. When cumulative DDL approaches your DFT, quads fatigue → downhill pace drops.
💡 DFT = your downhill fatigue threshold (depends on runner level). Change level above to personalize.
Show formula
paceLoss = basePace × (1 + max(0, ratio–0.8)²) − basePace
This is a heuristic model, not medical advice.
Powered by Open-Meteo, a free weather API aggregating multiple models.
Models used:
• ECMWF (European)
• DWD ICON (German)
• GFS (American)
Forecasts may differ from other services due to different model blending.
open-meteo.com ↗
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📊 Course Details
Route Map
Course Load
Surface Analysis
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Race Strategy
Set your target pace for different terrain types. Pace is in minutes per kilometer (min/km).
Enter your target finish time and adjust the pace ratios for different terrain.
How do you handle terrain? This adjusts your pace predictions:
Calculated Paces
Use your ITRA Performance Index to estimate race time. You can enter your score directly or calculate it from a past race.
📊 Route Effort Points
🏃 Your ITRA Index
Enter a past trail race result to estimate your ITRA index:
⏱️ Estimated Race Time
Adjust pace multipliers relative to flat pace:
Your Race Strategy
Strategy Details
🚰 Leg Summary
| Leg | Distance | Elevation | Est. Time | Arrival |
|---|
| KM | Elevation Change | Terrain | Surface | AID Station | Stop | Fuel | Target Pace | Split Time | Race Time | Clock Time |
|---|