(Great Western, South Fork of Provo Canyon)
The Windy Pass Trail climbs from the South Fork of Provo Canyon to a high ridgeline called Windy Pass. It begins smoothly at the Big Spring trail, then becomes steep and rocky. Starting at 5700 feet altitude, you'll climb 3300 vertical feet to the pass. Out-and-back, it's 13 miles round trip.
Even if the trail is buffed, you'll be climbing at a rate of about 800 feet per mile once you join the Great Western.
I found the trail cratered and churned from horses, with many long sections of loose rock that made climbing a challenge and descent "endo city." I'd reserve this trail for an advanced rider (with good rock-surfing control) who's looking for a climbing challenge. If that's you, go for it.If you choose to continue beyond the pass, you'll climb another 200 feet elevation, then begin dropping towards Bald Knoll. The trail links up with Forest Road 121 about 6.5 miles beyond the pass. This road drops into Wallsburg. Most riders who are doing a shuttle ride, however, do the ride in the opposite direction: from Wallsburg to Vivian Park. This saves a few hundred feet of climbing, and is (I'm told) significantly easier.
The difficulty of this trail will depend on the season, and on whether grooming (raking loose rocks) has been done. It's not your Momma's trail. It's a tough ride but fun for those who thrive on abuse. And the views are nice.
0.0 Singletrack on far end of parking lot (E 5700)
0.85 Fork L, cross road
1.15 Fork L GPS N 40° 19.192' W 111° 31.874' (E 5900)
Go down and through gully (R=Big Spring)
1.6 Keep R (L goes downhill to GW trailhead)
1.9 Great Western comes in on left
GPS N 40° 19.369' W 111° 31.391' (E 6300)
GPS N 40° 17.528' W 111° 31.842' (E 7600)
5.6 Hard R to go south (E 8200)
6.15 Trail turns back east (E 8700)
6.4 Keep R uphill, begin stiff climb at Water Hollow
GPS N 40° 17.103' W 111° 30.593' (E 8800)
6.55 At pass (if continuing to Bald Knoll, go L)
GPS N 40° 17.026' W 111° 30.617' (E 9000)
To start at the horse trailhead, continue up the South Fork road another 0.9 mile. Pull right into a gravel parking area just before the gate of the Trefoil ranch. The trail starts at the gate with 0.8 miles of doubletrack. GPS N 40° 19.540' W 111° 31.074'. This route saves about a mile of distance but only about 150 ft of climbing. I don't recommend it for bikes.
Single-page trail guide
GPS track files (right-click and "Save as..."):
GPX Windy Pass High-res topo for printing: View
Lodging, camping, shops: Links to Provo area resources