The Poison Spider Mesa trail is one of the "Must Do" rides of Moab. Combining physically demanding biking challenges with great views, this trail is for expert bikers. The trail can be ridden as an out-and-back, but here I describe a 13-mile loop that includes the infamous Portal Trail as the return-route off the mesa. Altitude gain is 1000 feet.
The Portal Trail starts as a narrow single-track, edging ever-closer to the vertical cliffs above the Colorado River. Remember to look where you're going, not where you don't want to go! Even on the rideable sections at the cliff-top, a long drop to the Colorado is just a few feet away.
The Portal Trail is a gnarly and dangerous return route. It can be fun for an expert biker, but there are sections where you should get off your bike as you carefully walk along the edge of the cliffs. This is a trail where overly confident bikers die.My brother-in-law's bike went over the cliff here. He did not. The bike, however, did not survive.
When you hit the paved road, go west downriver a couple of miles to your starting point.
0.4 Fork R
1.5 Keep R
1.6 Keep R
3.1 Fork L (diamonds) for less sand
3.2 Trails rejoin
3.6 Fork L (jeeps)
3.7 Trails rejoin again
3.9 Keep L
Follow painted jeeps
6.0 Fork R
6.5 At Little Arch (spur goes R downhill)
6.7 Fork L
7.2 Follow cairns uphill
7.6 Pass fence and drop-off warning sign
7.7 Fork R uphill
8.2 At rim. Portal Trail is singletrack on R
11 Bottom of Portal Trail, turn R on road
13 Right up to parking