Porcupine Rim
Exposed singletrack along a 1,000-foot cliff edge with views of Castle Valley. Relentless, technical, and a long way down.
Trail beta
Park at Sand Flats Recreation Area ($5 day pass per vehicle, $2 by bike) near the Porcupine trailhead, or self-shuttle with a car at the Hwy 128 finish. Most riders shuttle so it rides as a point-to-point descent: pedaling up Sand Flats Road is brutal and not worth it. Save energy for the rocky jeep-road chunder in the middle third and the notorious ledge drop near the end above the river. Session it or go around on the left. Expect other riders and hikers near the viewpoints.
When to go
Rideable March through November, with peak conditions in April-May and September-October. At 6,000 ft, Porcupine is the first La Sal foothill trail to open in spring and stays accessible longer than the higher-elevation Whole Enchilada top. Summer rides require dawn starts: the exposed sandstone routinely hits 100F+. BLM Sand Flats manages access; shuttle operators are BLM-permitted and e-bikes are prohibited on Porcupine Rim under those permits.
Shuttle
Shuttle saves the climb up Sand Flats Road, but plenty of people pedal to various put-in points.
Self-shuttle
Locals self-shuttle UPS/LPS constantly: park at the Sand Flats vault toilet, ride down, drive yourself back up to the top. Classic DIY move. Brings total time to ~2-3 hours with the drive back.