Biking & Mountain Biking--Bikes are not permitted off established roads at Rocky, and bicyclists will, in most cases, be sharing roadways with motor vehicles along narrow roads that have 5% to 7% gradients. However, bicyclists will still enjoy the challenge of the roadways and the beauty of the scenery. Remember, it's best to head out as early as possible because storms occur almost daily from June through September anytime after late morning. Storms cause dangerous lightning, wet and slippery road surfaces, and freezing temperatures that can lead to hypothermia.

One popular 16-mile ride with plenty of beautiful mountain views is the Horseshoe Park/Estes Park Loop. Head west from Estes Park on U.S. 34 past Aspenglen Campground and the park's Fall River entrance, and then turn back toward the east at the Deer Ridge Junction, following U.S. 36 through the Beaver Meadows park entrance. Allow 1 to 3 hours.

Bear Lake and Trail Ridge roads are also open to bicycles. Bear Lake Road climbs 1,500 feet over 8 miles from Moraine Park, a lovely glacier-created valley framed by mountains, to Bear Lake, the takeoff point for numerous trails into the backcountry. Stop at Sprague Lake and Glacier Gorge Trailhead along the way for parking, hiking, and photo opportunities. The round-trip takes about 2 to 4 hours.

Only strong cyclists should tackle Trail Ridge Road from the Grand Lake Entrance since it ascends 3,758 feet in just over 20 miles. About 10 miles of this attractive winding road are above 12,000 feet elevation -- which means less oxygen and colder air. Start out as early as sunrise to avoid the heaviest traffic on the narrow road, and also to avoid an all-too-likely summer thunder (and lightning) storm above the tree line. Temporary shelter can be found at Milner Pass, Fall River Pass in the visitor center and store, and in an emergency, in comfort stations at Rock Cut and Rainbow Curve. Allow 4 to 6 hours round-trip.

Old Fall River Road is also open to bicycles, but mountain bikes are recommended for this rugged ride.

A free park brochure, available at visitor centers, provides a map and information on safety and regulations.

Tours, rentals, and repairs are available at Colorado Bicycling Adventures, 184 E. Elkhorn Ave., Estes Park (tel. 970/586-4241). Bike rentals are about $15 to $40 for a half-day and $23 to $60 for a full day, depending on type of bike. The company also offers guided downhill trips in the park for about $65 per person, and also leads a variety of free group bike rides in the Estes Park area from May through September (call or check the website for the current schedule).

In Grand Lake, stop at Grand Lake Sports, 900 Grand Ave. (tel. 970/627-8124), for repairs, maps, and rentals, at rates similar to those in Estes Park.