Complex sentence: Stage 4, the Park City Criterium, was timed instead of measured: a one-mile loop with a 10% grade at 7,000 feet that would be ridden for 75 minutes.
Split into simpler sentences: Stage 4, the Park City Criterium, was measured by time instead of distance. The riders circled a one-mile loop with a 10% grade at 7,000 feet for 75 minutes.