Whirlwind Loop
The Whirlwind Loop is part of the Horsethief Area mountain bike trail system along Highway 313 northwest of Moab. The top of the loop is at 5700 feet altitude with a usual riding season of March through November. The lariat-loop itself is 2.4 miles long, but a minimum ride will be 6 miles, as you must ride other trails to reach this loop. This is an intermediate-technical trail.
Trail conditions, alignment, and connections will change. Use this guide at your own risk. 2015 UtahMountainBiking.com
Riding notes, Mustang to Whirlwind from Chisholm:
0.0   East from 313 (Chisholm) TH
N38 34.866 W109 47.857
0.5   L on Mustang Loop
N38 35.088 W109 47.586
1.3   Keep R (L = Whirlwind  joins)
N38 35.501 W109 47.388
1.4   Downhill L on Whirlwind
(R = Mustang continues)
N38 35.499 W109 47.308
1.5   Keep L (R = Wildcat)
N38 35.574 W109 47.234
2.4   Fork R (will return here)
N38 35.920 W109 47.300
2.6   7-up, turn around
N38 36.019 W109 47.225
2.8   Back at fork, go R
N38 35.920 W109 47.300
3.8   Join Mustang, keep L
N38 35.501 W109 47.388
3.9   Keep R this time, Mustang
N38 35.499 W109 47.308
5.1   Keep R (L = toward Getaway)
N38 34.909 W109 47.267
5.7   L on Chisholm
N38 35.088 W109 47.586
6.2   Back at parking
Getting there: From I-70 and Crescent Junction, drive south on US-191 for 20 miles (about 9 miles north of the Colorado River if you're driving out from Moab) to Highway 313. Drive uphill 11 miles.
Horsethief Campground: On your left at mile 11.8 from Highway 191. Use this trailhead only if you're camping. There is no general trailhead parking here. After claiming your camp spot, pedal to the east end of the eastern camping loop and fork south on the Chisholm Trail.
Highway 313 (Chisholm) Trailhead: At mile 12.5, spot the trailhead kiosk on the left side of the road. Turn into parking. Pedal east (away from the highway) on Chisholm to intercept the Mustang Loop in 0.5 mile.

Gemini Bridges Road (Getaway) Trailhead: For longer rides of the area trails. At mile 12.9, turn left at the Gemini Bridges sign. About 200 feet from the pavement, spot a small parking area on your left with the Getaway Trail just east of parking. Mustang forks away from Getaway 0.6 miles from the trailhead.
Bull Run Trailhead: Drive 1.1 miles down the Gemini Bridges dirt road, then turn right into the trailhead. Start your ride to the Horsethief Area trails by heading left on 7up.