What’s red, yellow, orange and black--equals just one--and feels endless.   You guessed it, fall riding on Park City single-track.   Southern Utah is famous for its autumn mountain biking, but while Moab is still baking in the mid-90’s, Park City is a cool 70 degrees with clear skies and firm black dirt.   Locals know that this is the best time of year to ride the Wasatch.   The crowds are gone, the trails are smooth, and the colors are spectacular.     With cheap lodging, 2-for-1 restaurant deals, and perfect weather, it’s also a great time to come visit.   Wake up to blue skies, find breakfast on Main Street, enjoy hours of colorful riding, return to Historic Park City, enjoy a local brew, appease your spouse with a fantastic dinner, and still have money left for that new bike (hint: great sales begin after Labor Day).