View to the north as J-Boy approaches the Dinosaur Tracks road. Photos and trail...
View to the north as J-Boy approaches the Dinosaur Tracks road. Photos and trail review by Bruce on June 23, 2016.
J-Boy Trail

The J-Boy Trail lies on the eastern end of the Red Fleet mountain bike trail area . As of 2016 it's the newest addition to the area. It's 2.5 miles long with around 400 vertical feet of elevation change. J-Boy can be done as a short loop (see below) or as part of a longer ride when combined with other area trails.

The portion of J-Boy south of the Dinosaur Tracks road is somewhat technical. Skilled intermediates can muddle through, but it's intended for expert riders. I found J-Boy to be the most interesting and fun ride of the Red Fleet area.
View south from the rides highest point. The water is Red Fleet Reservoir.
View south from the ride's highest point. The water is Red Fleet Reservoir.
Typical trail on the northern half of the ride -- undulating dirt in a forest of...
Typical trail on the northern half of the ride -- undulating dirt in a forest of juniper.
Many riders start with the first portion of Handsome Cabin Boy , then after riding J-Boy continue to Jazz Chromoly for a longer continuous loop ride. (See the big loop ride description below.)

The Three Amigos loop ride is reached via J-Boy's northeastern side. A detour onto this lariat loop makes a satisfying longer ride.

As of 2016, the Red Fleet trails do not have dedicated mountain bike trailheads. J-Boy crosses the paved road at the trailhead for the Dinosaur Tracks hiking trail. There's a bathroom and map kiosk here. This is an easy way to find the trail, but on weekends the parking lot is often crowded -- and if so, a kind bike rider will save space for hiking families by parking elsewhere.
The Dinosaur Track trailhead. Im standing at the entry to the J-Boy trail north ...
The Dinosaur Track trailhead. I'm standing at the entry to the J-Boy trail north of the road. The southbound trail is to the left of the kiosk (combined with the hiking trail for the first 100 feet).
Climbing south (counterclockwise) away from the trailhead. Navajo or Nugget sand...
Climbing south (counterclockwise) away from the trailhead. Navajo or Nugget sandstone forms the "pillows" on the skyline.
The Dinosaur Tracks trailhead is the beginning point for the short loop ride, described below. It's a quick but satisfying "while you're in the area but don't have any time" ride. Heading clockwise, this mini loop climbs the southern limb of J-Boy before descending to Handsome Cabin Boy northbound, then descends east on J-Boy back to the trailhead. It's a fast 2 miles with 200 vertical of climbing.
A nice longer loop that hits the major Red Fleet trails combines Handsome Cabin Boy with J-Boy, then finishes with a cruise around the top of Jazz Chromoly It's 7.8 miles with around 2000 vertical feet of climbing. See the ride directions further down the page. Because this loop passes the entry to the Three Amigos lariat ride, you can easily add that trail for a satisfying longer ride.

(Note: In 2016 there are ominous warnings about blasting in the Three Amigos area, posted by the trailmap sign near the Dinosaur Tracks trail crossing. The trail may be subject to intermittent closure. Check current status before riding and obey any closure signs!)

View of the same area as above, but heading north (counterclockwise).
View of the same area as above, but heading north (counterclockwise).
Short Loop Ride  from Dinosaur Tracks TH  (2 miles)
Little Rocky pauses to enjoy the view about 100 vertical feet into the climb on ...
Little Rocky pauses to enjoy the view about 100 vertical feet into the climb on the Short Loop.
From the parking strip, find the trail heading south between the bathroom and the kiosk. After 100 feet, fork right on J-Boy. (The Dinosaur Tracks trail beyond this point is hiking-only!)

After a bit of up-and-down you'll begin a serious climb along the edge of the tilted sandstone. (The layers are tilted here due to the uplift that raised the Uintah Mountains.) You'll gain about 150 vertical feet over the 1/2 mile up to the viewpoint.

Enjoy the views as you reach a viewpoint at 6000 feet elevation. You can see the peaks of the eastern Uintahs to the northwest. To the south you can see Red Fleet Reservoir and the rolling Nugget (Navajo) sandstone behind it.
And this is the trail -- straight up this strip of sandstone along the cliff edg...
And this is the trail -- straight up this strip of sandstone along the cliff edge.
The trail continues southeast from the viewpoint on the clockwise short loop.
The trail continues southeast from the viewpoint on the clockwise short loop.
After a quick cruise on top, you'll begin a somewhat technical drop down to the Handsome Cabin Boy (HCB) trail. Good stuff, but over too quickly. The tech stuff is now behind you.

Fork to the right on HCB. Cross the road. At the next trail fork, turn right on J-Boy eastbound.

J-Boy will undulate along the skirts of the mountain. When you hit open rock in a wash, you're almost done. J-Boy will pop to the right out of the wash to the road at the trailhead.
Dropping through some rough rock, with Red Fleet straight ahead.
Dropping through some rough rock, with Red Fleet straight ahead.
Big Loop Ride -- HCB to JB to JCM (8 miles)
Interesting spot on the trail, looking south. The path takes you between the cli...
Interesting spot on the trail, looking south. The path takes you between the cliff and the unusual stone pillar near the tree. Exactly a handlebar's width plus an inch.
This 7.8 mile loop starts on Handsome Cabin Boy , detours onto J-Boy, then continues to the top side of the Jazz Chromoly loop. You'll do the technical part of J-Boy in the opposite direction (south to north) from the mini-loop above.
At the Jazz Chromoly / HCB trailhead, go to the road and find Handsome Cabin Boy a bit to the east. Follow HCB clockwise 1.1 miles, then detour onto J-Boy. You'll make a fairly stiff and technical climb along the edge of the cliffs to reach the viewpoint at the top.
The trail takes a couple of switchbacks as it works along the cliffs between HCB...
The trail takes a couple of switchbacks as it works along the cliffs between HCB and the summit.
View from the junction of HCB and J-Boy north of the road.
View from the junction of HCB and J-Boy north of the road.
In this direction, the descent on J-Boy is fairly straight and uncomplicated. When you reach the road, find the continuing trail across the road opposite the uphill corner of the parking strip.

Take J-Boy uphill and veer right as it rejoins HCB. At the next trail fork, keep right on J-Boy as HCB goes left.

Pass the Three Amigos trail, keeping left.

(Check the status of Three Amigos before detouring onto that trail. There's intermittent blasting in the area, subjecting the trail to closure!)

Go left again as the trail splits in a sagebrush sea near the road. Climb up and across the road as you rejoin HCB. (Alternate: just coast down the pavement to the cattle grate.) HCB will come back to the road at a cattle grate. Left of the grate is a connector to Jazz Chromoly . Keep right to head uphill on JCM.

The northern portion of J-Boy is mostly undulating dirt ribbon. Were facing east...
The northern portion of J-Boy is mostly undulating dirt ribbon. We're facing east, descending back to the Dinosaur Tracks trailhead.
A bit of slickrock north of the road near the trailhead.
A bit of slickrock north of the road near the trailhead.
On Jazz Chromoly, keep right at all the trail forks for the outer (northern) side of the trail system. It will drop to a wash southbound along Highway 191, then climb east uphill to the trailhead.

Bottom Line!
Very nice trail for skilled riders. Beautiful views, varied terrain. Worthwhile ride, whether you make it a destination or just happen to be in the area.

Riding notes, little J-Boy loop:
Dinosaur Tracks trailhead
0.0   Dino tracks trail N40 35.740 W109 26.178
        100 feet, fork R on J-Boy
        N40 35.720 W109 26.188
0.6   View, highest point
1.2   Hard R on HCB
        N40 35.848 W109 26.657
1.4   Cross road to slickrock
        N40 35.925 W109 26.403
1.7   R downhill on J-Boy
        N40 36.032 W109 26.225
2.0   Cross road to parking
Riding notes, HCB/JB/JCM loop:
Jazz Chromoly trailhead
0.0  Exit parking, L on paved road
       N40 35.923 W109 27.470
       100 feet later, R on narrow ST
       N40 35.926 W109 27.430
0.6  Keep straight R (L=bailout to road)
       N40 35.720 W109 26.896
0.7  Fork, L through wash and up rock
       N40 35.619 W109 26.858
1.0  Climbing eases 
       (you've done 200 vertical in 0.4 mi)
1.1  Fork R to J-Boy)
       N40 35.847 W109 26.653
1.7  Viewpoint, begin descent
2.2  L uphill on road 100 feet
       R to trail  N40 35.740 W109 26.178
2.6   Veer R (rejoin HCB)
        N40 36.031 W109 26.219
3.1   Keep R on J-Boy (L = HCB)
        N40 36.351 W109 26.127
3.3   Keep L (R = Three Amigos)
        N40 36.408 W109 26.268
3.5   Fork L N40 36.256 W109 26.412
3.6   R up to paved road
        N40 36.181 W109 26.373
        Cross road
4.0   Cross road and cattlegrate
        N on ST N40 36.142 W109 26.621
4.1   Join Jazz Chromoly, keep R
        N40 36.238 W109 26.713
4.8  Turn L (west) N40 36.784 W109 26.862
5.7   Rightmost fork
        N40 36.550 W109 27.397
6.3   Alternate rejoins on L
        N40 36.094 W109 27.626
6.4   Fork hard R 
        N40 36.033 W109 27.728
7.0   Keep R N40 35.955 W109 27.894
7.8   Back at parking
Map of the J-Boy area
Map of the J-Boy area
Getting there...

Jazz Chromoly Trailhead:  
In Vernal on US-40 (the main drag), turn north on US-191. Drive to mile 10.7 and turn right at the paved road signed "Red Fleet Dinosaur Trackway." Drive uphill 0.6 miles. At the top of the hill, turn left onto a dirt road and immediately park in the wide area on the left. On your bike, go back to the paved road and turn left. 100 feet later, find the narrow Handsome Cabin Boy (HCB) singletrack on the right (south) side of the road, heading south. J-Boy is found 1.1 miles along HCB.
Cattle grate parking:  Drive to the cattle grate at mile 1.5 and park in the small spot on the right side of the road. Find Handsome Cabin Boy southbound along the fence and follow it until it crosses the road again. J-Boy forks left immediately as the trail leaves the road.

Three Amigos dirt road:  About 1/10 mile uphill from the cattle grate (around mile 1.6 from US 191), turn left to a dirt road. Find a parking spot along the edge of the road. Backtrack to the paved road, turn left uphill, and go 100 feet to find J-Boy on the left (uphill) side of the road.
Dinosaur Tracks trailhead:  Drive to the Dinosaur Tracks parking area at mile 2.4 from US 191. J-Boy is across the road from the uphill end of the parking strip, and also 100 feet down the dinosaur tracks hiking trail.
Riding resources for this trail:
Single-page riding guide
GPS track files (right-click and "Save as..."):
    J-Boy track
    Mini-loop track
    HCB-JB-JCM track
    Multi-track area file
Area topo map for printing:   View map
Lodging, camping, shops:   Links to Vernal area resources