Novice
For the aerobic-junkies out there who aren’t quite ready for stump-jumping or cliff-diving on their steel steeds, the Rattlesnake Wallman Trail is a perfect training ride or evening spin. In about an hour, you can complete an 8.25-mile loop with a total elevation gain of almost 1,400 feet. The trail is mostly single-track, so do keep a lookout for other users. The ride starts with a casual climb, then a short steep climb, then a downhill cruise back to where you started.
From the Rattlesnake Recreation Area Trailhead, travel north out of the parking lot for ½-mile. You’ll see a sign for Spring Gulch Trail on your left, take that trail and begin a slow 2.5-mile climb. Getting close to the top you will see the sign for the Wallman Trail on your right. After getting on this trail you will cross a small creek and begin a short, steep ascent to the peak of your ride. Stop for a moment at the top, then ready yourself for a fun, safe blast that winds down the mountain and connects back with the Rattlesnake Corridor Trail. 
Take a right on this trail and follow it south back to the parking lot. Note: there is a 10 MPH speed limit on the lower part of the main Rattlesnake Trail.
The Rattlesnake Wallman Trail was reworked in a collective effort by the US Forest Service and volunteers from LIMB (Low Impact Mountain Bicyclists of Missoula) and IMBA (International Mountain Biking Club) to provide an enjoyable alternative to some of the area’s high-traffic trails.
Intermediate
For a longer, steeper, more memorable ride, try the Rattlesnake-Spring Gulch-Curry-Dropout Trail, or some just call it “Dropout.” This winding, multi-path ride covers just over 10 miles and climbs just over 1,700 feet. It’s best to have a map with you on this one, as the Spring Gulch and Curry trail systems can be the trickiest part to navigate. But ride it a few times and you’ll be able to guide your friends or date through a dizzying and dazzling 1.5-hour mountain bike ride.
Start the ride at the Rattlesnake Recreation Area Trailhead and head north out of the parking lot, alongside Rattlesnake Creek. At the Spring Gulch Trail make a left. Follow this trail to the Curry Trail intersection and take the dirt road on the right. You will follow this road up the east side of Spring Creek. Cross the footbridge where the trail intersects back with the Spring Gulch trail (a singletrack). 
Take this back down and then turn right on Curry Trail. At the very next intersection, turn left, and then make a right onto Curry Ridge Trail. After 1.25 miles, make a left on a very short connecting trail that takes you up to the Stuart Peak Trail. Make a left and follow this until you come to section on the trail that diverts around a large log. After the large log, turn on the first trail on your left, which is the Dropout Trail. This singletrack will take you back into Sawmill Gulch, where you can take the singletrack trail back to the parking lot to finish the loop.
Experienced
Ready to bust a lung, pound some miles and bag a peak, proverbially speaking? Try the Stuart Peak Trail for an all-day adventure on bike and foot. A relentless 19-mile journey, with four of those on foot, this ride will require some planning, good weather and a pair of hiking shoes. You’ll climb about 3,000 feet and hike up another 1,000 feet, and you’ll come down on some sweet singletrack after topping Stuart Peak, one of the Rattlesnake’s highest points (elevation 7,960).
To start this epic ride, head west out of the parking lot at the Rattlesnake Recreation Area trailhead and ride up the singletrack north of Sawmill Gulch Road. This trail will turn into a road just before the gate. Continue on this road for about .5 miles and then take the trail on the right which will climb steeply to the top of a ridge. When you crest this ridge, follow the ridge for a short bit before taking the trail on your left. This trail is level at first then climbs another ridge between Sawmill and Grant Creeks. Now turn right and follows the signs to Stuart Peak. As you proceed toward Stuart Peak, you will pass two trail junctions: the first is a trail coming up Curry Gulch and the second is a trail coming up Grant Creek.
When you reach the Snowbowl Overlook, stop and take a moment to enjoy it. After this, the trail dips into Spring Gulch and joins the Spring Gulch Trail. Take a left here. Now grind through an approximate 4.5-mile climb to the Wilderness Boundary, which is clearly marked. You cannot travel any further on your bike, as bicycles are illegal in the Wilderness Area. Park your bike and continue up the trail for about 1.5 miles and then leave the trail, going right, and climb to the top of Stuart Peak. To return to the parking area, follow Spring Gulch Trail, which connects to the Rattlesnake Corridor Trail and leads you back to where you started.