Thunder Valley Motocross Park sits in Lakewood, Colorado, just west of Denver, at an elevation of over 5,500 feet. Like the supercross round at Empower Field a few weeks earlier, altitude is the defining characteristic of this event — thin air affects engines, riders, and strategy in ways that teams spend enormous resources preparing for.
The Altitude Challenge
At 5,541 feet, the power reduction on a naturally aspirated motocross engine is significant — teams typically see a 15-17% reduction in peak horsepower compared to sea level. The fuel mapping changes required for Thunder Valley are extensive, and teams that get it wrong find their riders struggling with sluggish, unresponsive machinery from the opening moto.
For the riders, altitude means each lap of a 30-minute moto demands more cardiovascular output than the same lap at sea level. Riders who have spent time training at altitude or who arrived in Colorado several days early to acclimatize carry a meaningful advantage into both motos.
"Thunder Valley is where fitness and preparation separate the field more than raw speed. You can outride someone all season and still lose to them at altitude."
— Moto, Moto Track GuideThe Track Itself
Beyond the altitude challenge, Thunder Valley is a genuinely difficult track. The hard-packed Colorado dirt becomes extremely slick when it dries out in the afternoon heat, and the track features several high-speed downhill sections where commitment and bravery are mandatory. The start straight runs uphill — one of only a few outdoor nationals with an uphill gate drop — which changes the first corner dynamics completely.