The course
Quicksilver runs 100 percent on unpaved trail through Almaden Quicksilver County Park, an old mercury-mining landscape in the hills above the Santa Clara Valley. The route strings together hilly singletrack and old fire roads through oak forest, open meadows, and exposed ridgelines, and you get long views out toward the Santa Cruz Mountains. The 100K covers about 62 miles with 13,000-plus feet of climbing, the 50K about 30 miles with 6,000-plus feet, and the elevation swings between roughly 400 and 3,000 feet the whole way.
A dark start and relentless climbing
The 100K starts at 4:30 AM, in the dark, and you need a light source just to begin. From the Hacienda entrance the course climbs almost right away and then basically never stops climbing or descending. There is very little flat ground out here. The vert is built from a lot of repeated climbs instead of one big summit, with most pitches in the steep one-to-two mile range and a few longer sustained grinds of four to six miles, including a section runners have nicknamed for how much it hurts.
Here is the trap. Those early miles in the cool dark feel runnable and easy, and it is really tempting to bank time on the first climbs. Climb the opening by effort, power-hike the steep pitches with purpose, and save your running legs for the gentler grades. The course only gives that time back later if you stay disciplined early.
Exposed ridgelines and the heat
A lot of Quicksilver runs on open ridgeline and fire road with hardly any tree cover, and that is the defining challenge of the race. In a cool, overcast year the course is forgiving. In a warm May those exposed sections turn into a heat-management problem by late morning, and the same climbs that felt easy in the dark feel brutal under the midday sun. Heat, not altitude, is what unravels most well-trained runners out here.
On the exposed stretches, your hydration and sodium discipline matter more than anything. Carry enough fluid to cover the gaps between aid, keep your electrolytes up, and use whatever cooling the aid stations have. Treat the hottest hours as a patient survival game, and then run again once the afternoon eases off.
Where the race is won or lost
The course climbs and descends in equal, enormous measure, so the downhills are every bit as decisive as the climbs. All that descent shreds quads that are not ready for it. Bomb the early downhills and you pay for it in the back half, when every remaining descent turns into a grind. Quad-specific downhill training is some of the most race-specific work you can do for Quicksilver. The climbs are not what get you here, the descents are.
The 100K also loops through the same big back-of-course aid station twice, so you hit familiar checkpoints more than once. Use that to your advantage, know your splits, and keep moving with margin against the intermediate cutoffs. The people who finish strong are the ones who paced the climbs by effort, protected their legs on the descents, and stayed ahead of the heat.
Aid stations and cutoffs
The course is supported by fully stocked aid stations with water, electrolyte fluids, food, and volunteers, plus a big back-of-course aid station the 100K visits twice. The 100K has a 17 hour overall limit, and every finisher inside it earns a Western States qualifier. The 50K has an interim cutoff around mile 22 and an afternoon course cutoff.
Several checkpoints have firm intermediate cutoffs, so you cannot just hike the front half casually, especially once the heat starts building. Check the official Quicksilver runner guide for the current edition. It publishes the aid-station chart and the cutoff times, and you want to build your pacing plan backward from those with a buffer.
Pacing strategy for Quicksilver
A course this vertical, this exposed, and this short on flat ground rewards patience and punishes ego. Pace Quicksilver by effort and by grade, not by the flat-ground numbers off your home training runs.
Pace the climbs by grade, not by clock
With 13,000-plus feet of gain packed into 62 miles, your moving pace is going to swing all over the place between the steep climbs and the runnable grades, and that is exactly how it should be. Power-hike the steep pitches efficiently and run the gentler terrain. Trying to hold one steady minutes-per-mile number across all this up and down is the fastest way to cook the climbs and have nothing left for the descents and the heat.
Use our free grade-adjusted pace calculator to turn your flat fitness into honest effort targets for the steep Quicksilver climbs. That way you know whether you are pacing the vertical in a way you can hold, or burning matches you are going to want back at mile 50.
Protect your quads for the descents
The course descends as much as it climbs, so downhill running is the hidden crux. Hold back on the early descents, run them controlled and light instead of letting gravity hammer your legs, and your back half is going to be a lot better for it. The people who finish strong almost always still have working quads at mile 45.
To set a finish goal that actually accounts for all that vertical, use our vert-aware race time calculator. It works the climbing into your projected finish, so you are not stuck on a flat-course estimate that the Quicksilver hills will quietly tear apart.
Plan around the heat and the clock
Quicksilver is not at altitude, so your limiter is the constant vert plus whatever the May sun decides to do on race day. Pace the exposed midday hours conservatively, keep your core temperature down, and expect your splits to slow through the hottest part of the afternoon. If you stayed disciplined early, your pace can steady back up as the heat eases. But only if you did not blow up chasing that cool morning.
And if you want to know how your fitness from a recent race carries over to a climbing-heavy 100K or 50K like this one, our race equivalent calculator helps you reality-check the goal before you lock in a finish time.
Fueling strategy for Quicksilver
A long climbing day that can get hot in the open makes fueling and hydration just as decisive as fitness. The heat on the exposed ridges is the thing that wrecks most well-trained runners, so plan for it.
Carbs: ramp to the high end, on a trained gut
For an effort this long, aim for roughly 60 to 90 grams of carbohydrate per hour, and lean toward the high end once your gut is trained to handle it. Use a glucose-plus-fructose blend so you can absorb more than a single sugar lets you, and rehearse your exact hourly carb number on long training runs, so that by race day 80 to 90 g/h feels routine and not like an experiment.
Heat makes all of this harder, because a hot stomach takes less. That is one more reason to practice fueling in race-like heat and to keep eating through the ugly hot hours, when your appetite drops off but your engine still needs the fuel.
Sodium and fluid: built for the exposed climbs
On the open Quicksilver ridgelines you can lose a lot of sweat on a warm day, so bias your sodium toward 500 to 700 mg per liter of fluid and carry enough to cover the exposed climbs between aid stations. Cramping, a sloshy stomach, that wrung-out feeling late in the race, those are usually fluid and sodium balance problems and not fitness problems.
Dial in a personalized plan with our free ultra fueling calculator. Put in your weight, your goal time, and the expected heat, and it gives you a carb, sodium, fluid, and caffeine prescription per hour built for the Quicksilver duration and conditions. Then go test it in training.
This guide is for planning and training purposes and reflects publicly available information about the Quicksilver Endurance Runs. Race details, including the date, distances, course, aid stations, and cutoffs, can change year to year. Always confirm the current specifics on the official Quicksilver Running Club race website before you train or travel.