Castro Valley, CA, United States · Saturday, September 26, 2026

Fixed Distance 100K

Dick Collins Firetrails 100 km

10 days to go
100 km Distance
3,000 m Climbing
9.5 Grit · Elite / extreme
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37.6941° N, 122.0863° W© OpenFreeMap © OpenMapTiles Data from OpenStreetMap

What the course asks

Climbing rate 30 m / km Rolling. Moderate undulations. Requires consistent effort across varying grades.
Field size ~24 Small. Long stretches with nobody in sight.

DUV results for the 2025 edition (100km) — finishers only. Starters are not published, so the field was at least this big and no finish rate can be given.

Typical conditions, September

Daytime high 28°C
Night low 11°C
Rainfall Dry — rain unlikely
Daylight 12 h 03 m of light

Regional 2001-2020 average for September — NASA POWER, grid elevation 233 m. Not a forecast.

The Aid Station

Course-specific beta from the community

⛰️ terrain

This is a rolling course. Expect fast, runnable sections where rhythm is key.

By UltraHub Expert
👟 gear

With trail terrain, choose a shoe with moderate cushioning for optimal performance.

By UltraHub Expert
🥤 nutrition

For 100km+ efforts, prioritize real food at aid stations to prevent palate fatigue.

By UltraHub Expert

Gear for this race

Chosen for 100 km of trail with 3,000 m of ascent.

  • Trail Running Shoes30 m of climb per kilometre — grip and rock protection before cushioning.
  • Race NutritionPast 100 km the palate quits before the legs do — carry more than one flavour.
  • Hydration VestsPole attachment and chest-strap stability on steep ground.
  • Trekking Poles3,000 m of ascent to walk up.
  • Headlamps100 km almost certainly means running into the night.

Adidas

Terrex Agravic Speed Ultra

★★★★★ 4.5

Salomon

Aero Glide 4 Grvl

$159.95 ★★★★★ 4.5

Maurten

Gel 100

Hydrogel technology for 25g carbs per gel with minimal GI distress.

$3.5 ★★★★★ 4.7

Nathan

VaporKrar 12L

12L race vest co-designed with ultra champion Rob Krar, with insulated bladder pocket.

$170 ★★★★★ 4.6

LEKI

Ultratrail FX.One

Ultra-light carbon folding poles (135g each) designed for mountain ultra racing.

$200 ★★★★★ 4.6

Nitecore

UT32

Dual-beam trail running headlamp (1100 lumens) with spot and flood beams.

$100 ★★★★★ 4.5
All gear guides →

Course Notes

The race will be held at Lake Chabot Marina. The course follows the classic Dick Collins Firetrails course and add and out-and-back along the Nimitz Trail, then down Conlon Trail to intersection of Wildcat Creek Trail and Belgum Trail.

Similar races

Other 100K trail ultras, closest in distance first.