Southwest of Bolzano in the Brenta Dolomites, this area has an extensive trail system in the Adamello-Brenta National Park surrounding Madonna di Campiglio. Pinzolo has a tough 24 mile mountain bike trail, and theres a nice course near Campo Carlo Magno.
To reach this area from Milan, head east on Route A4. In Bergamo, follow Route SS42 north. In Dimaro, turn south on Route SS239 into Madonna Di Campiglio.
Overall, Madonna Di Campiglio is the 3rd most popular mountain bike trail of all 46 mountain biking rides in Italy.