Porcupine Rim has some of the most photogenic mountain biking anywhere. Located just outside of Moab, this is the eye-popping clifftop singletrack that catalog shots are made of. It is a portion of the famous Whole Enchilda downhill ride that begins in the La Sal Mountains and finishes at the Colorado River.
What's known as Porcupine Rim is a continuous collection of three trails, UPS (Upper Porcupine Singletrack), LPS (Lower Porcupine Singletrack), and Porcupine Rim Trail. Together they total about 17.5 miles and make the lower half of the Enchilada. You can ride all or part of this section by beginning in Sand Flats Recreation Area. The Sand Flats Road leads upward for about 10 miles to the LPS trailhead and keeps going beyond that into Manti-La Sal National Forest to access the UPS trailhead via Kokopelli's Trail four-wheel drive road. The shuttle from Highway 128 all the way up Sand Flats Road takes well over an hour, but you can arrange a drop-off and pick-up with one of a few companies in Moab. Companies may only offer shuttle for the Whole Enchilada, however, not Porcupine Rim on its own.
The trail follows the top of a 1,000-foot escarpment above Castle Valley, which is featured by sculpted sandstone towers and rimmed by distant cliffs. The actual trail runs a safe distance from the edge, but you can live dangerously on a few sections of slickrock if you choose to venture closer. It is all downhill with the exception of a few short climbs, but it is all very technical with uneven rocks, drops, and tight turns. Drops may be smooth rollers or sharp ledges, so don't be ashamed to scout. There are good but short flowy sections as well as some parts through soft sand. Overall the trail is suitable for intermediate to advanced riders. Experts can find more exciting variations in some places, such as The Notch alternate route of LPS—a very steep rock chute to a 90-degree turn.
The most scenic stretches are UPS and LPS, which are both singletrack more or less right on the rim. Below LPS the trail joins the Porcupine Rim motorized trail and moves away from the rim for the remainder of the ride. Motor traffic is generally low, however, so you are likely to see only other mountain bikers. After several miles on this double track the trail switches back to non-motorized singletrack for the final few miles to the Colorado River, and views get really good again as you descend into the canyon. The terminus is at Highway 128 near Grandstaff Campground.