Eryri 100K

Race strategy

Hold a steady pace and save energy for every section.

• 882m descent. Go easy, save your quads.
• Steep 39% wall. Control your pace and stay focused.
• Final 749m descent. Save your legs to go all out on it.
• Long race. Control your HR and effort. Early mistakes cost the most.
• Control your HR on the first mountain, save your quads on the descents until 81.8km, then run your race pace, and start the final descent from 96.3km under control, then go all out near the bottom.
• Start · 0.0km–1.5km · Race-day nerves push your heart rate up: don't follow the crowd, find your own rhythm.
• Settle in · 1.5km–13.8km · Climb of 875m, descent of 882m averaging 13%. Ease in: hold back more than feels necessary. The race is still ahead. Climb by heart rate or breathing, not pace. This descent is hard on the legs: short steps, stay in control, poles if you have them. Hike the steepest pitches.
• Work · 13.8km–55.5km · Climb of 750m, descent of 708m averaging 12%, descent of 569m averaging 21%. Plus 3 more climbs. This is where the race is built: steady, solid effort. Climb by heart rate or breathing, not pace. This descent is hard on the legs: short steps, stay in control, poles if you have them. Running pays off here: run wherever you can. Hike the steepest pitches.
• Fade · 55.5km–96.3km · Descent of 652m averaging 8%, climb of 972m, high point 1045m, descent of 902m averaging 14%. Plus 2 more climbs and 1 descent. Your energy fades, and that's normal: hold a steady effort and stop counting the miles. Climb by heart rate or breathing, not pace. This descent is hard on the legs: short steps, stay in control, poles if you have them. Running pays off here: run wherever you can. Hike the steepest pitches. Your heart rate drifts down on its own: don't chase your early-race numbers, go by feel.
• Home · 96.3km–106km · Descent of 749m averaging 8%. No heroics: settle back into your own effort and hold it to the line. Very long descent: first half under control, then even, let go only near the end.

Course

The course climbs 5800m+. With 54m/km of climbing, this is a true mountain course with sustained climbs and descents. By gradient, 39% of the distance is uphill, 39% downhill and 22% flat. The longest climb runs 7.6km at an average 9.9% grade (750m of vertical). The longest descent runs 9.4km at an average 8.0% grade (749m of vertical). The steepest climb averages 39.2% over 0.4km. The steepest descent drops at 38.7% over 0.4km. Surface: 46% trail, 24% smooth, 18% technical, and 9% road. Flat-equivalent effort: 158.0 FlatKM.

Summits

The highest summit on the course is Snowdon (1085m), 75.7km from the start. Other named summits along the route: Clawdd Coch (931m) and Moel Siabod (872m).

Poles

Trekking poles are worth taking: about 13.4km of the course favours them.

Quad damage

Quad damage risk is high (index 57 of 100), with 42% of the load in the first half: 5 critical descents, the last of them run on already damaged legs. Downhill-specific preparation and a controlled early pace pay off here.

• Control your HR on the first mountain, save your quads on the descents until 81.8km, then run your race pace, and start the final descent from 96.3km under control, then go all out near the bottom.
• #1 · 6.8–13.8 km · 882 m D−, -12.6% · 91.9 km ahead → control
• #2 · 21.4–27.5 km · 708 m D−, -11.6% · 78.2 km ahead → control
• #4 · 48.5–51.2 km · 569 m D−, -20.7% · 54.5 km ahead → control
• #3 · 55.5–63.9 km · 652 m D−, -7.8% · 41.8 km ahead → control
• #5 · 75.5–81.8 km · 902 m D−, -14.5% · 24.0 km ahead → control
• 96.3–105.7 km · 749 m D−, -8.0% · 0.0 km ahead → even, first half under control, let go at the end
• Plus 1 more notable descent not listed: your pace.

Weather

On race day, start temperatures have historically ranged from 7°C to 11°C, with around 5°C at the highest point; the chance of precipitation is about 49%. Heavy rain of 10.0mm or more falls on about 6% of days around this date.