In 1986, Tomac made two significant decisions: he relocated to Southern California, and left BMX competition in favour of mountain bike racing. He continued to ride for Mongoose. By the autumn of that year, he had won his first two major mountain bike events: the Ross Fat Tire Stage Race in Massachusetts and the Supercross Mountain Bike Exhibition race held at the Los Angeles Memorial Coliseum. Mongoose marketed a "Tomac Signature Edition" model in 1987, which reflected his increasing profile within mountain biking culture. Tomac achieved a few more notable wins during that year, including a second win in the Fat Tire Stage Race and three National XC Series rounds.