Two GM engineers are taking a dealer-accessible Colorado ZR2 Bison into one of North America’s more demanding off-road events. Nicole McKinnon, a program manager for offroad racing at GM, and Savannah Theisen, a vehicle software and integration lead, enter the 2026 Rebelle Rally as Team 125 starting next week, running roughly 1,500 miles across three states over eight days.
McKinnon competed in the event in 2024 and came away convinced the ZR2 Bison had more to give. Theisen is a first-timer. They met at a GM women’s networking event, discovered they both keep chickens, and named themselves the Milford Offroad Chicks. The team dynamic is built around interchangeable roles: McKinnon handles primary driving duties, Theisen primary navigation, but both are trained to swap when conditions demand it.
The truck they are running is an American Expedition Vehicles collaboration on the ZR2 Bison platform, equipped almost entirely with GM and Chevrolet Performance parts. The build includes an AEV heavy-duty winch-capable front bumper, larger fender flares, 17-inch beadlock-capable wheels, 35-inch MT tires, boron-steel skid plates, rocker protection, and front and rear Multimatic Jounce Control Dampers. The point, per McKinnon, is deliberate: show that a warranty-backed, largely dealer-accessible truck can handle a serious competitive event without needing bespoke fabrication.
The Rebelle Rally’s rules enforce exactly that standard. Vehicles must be currently in production, and a model similar to the competition truck must be publicly available for purchase within 180 days of the event. Tires are capped at 37 inches and must be obtainable through standard dealers or normal online retail. No trophy trucks. Aftermarket suspensions may be permitted, but the emphasis is on production-based hardware.
Now in its tenth year, the rally fields 65 two-woman teams and holds its place as the longest competitive off-road rally in the United States. Toyota and Ford typically send multiple factory-backed teams, which makes the GM pair one of the smaller manufacturer entries by headcount. Speed is irrelevant to the scoring: teams collect points by reaching 20 to 30 checkpoints per day using only paper maps, compasses, and rulers. GPS devices are sealed at the start and stay that way. Some checkpoints are flagged visibly; others require clicking in with a logging device at coordinates that have to be plotted by hand. Miss the target radius and the points disappear.
Days start at 5 a.m. with a cowbell. Route strategy happens in the predawn hours. The mental arithmetic of checkpoint selection, terrain routing, and risk management runs continuously for eight days, with each team camping in the field between stages.
McKinnon’s quote captures the partnership logic plainly: “You’re within five feet of each other all day, and teaming with someone with a good attitude is important. You can’t be mopey or linger on mistakes.” Theisen’s approach to uncertainty is equally direct: “I’m not one to think about what could go wrong, but how we can make things go right.”
The framing from McKinnon about the truck matters beyond the rally entry itself. Chevrolet has positioned the ZR2 Bison as its most capable factory off-road product in the Colorado lineup, with the AEV collaboration distinguishing it from the standard ZR2. Running it through a multi-day desert navigation event, on largely stock hardware, against teams in dedicated off-road vehicles is a live durability argument that no press drive can replicate.
If the ZR2 Bison makes it through eight days of Nevada and California desert without needing the recovery gear Team 125 packed just in case, that outcome carries more weight than any product comparison chart.
Source: Chevrolet. Images courtesy of Chevrolet.
