Grand Canyon National Park

Bicycling can be perilous on the park's canyon-side byways, where drivers rubberneck the gorge as if it were a grisly automobile accident. Complicating the problem are narrow roads, heavy traffic, and distracted pedestrians. During the next few years, however, cycling should become one of the most pleasant experiences inside the park. As part of the park's General Management Plan, private vehicles will be barred from most areas along the canyon's South Rim-currently the busiest part of the park. In their place will be light rail, alternative-fuel buses, and a new 33-mile-long, rim-side greenway for bicyclists, walkers, and equestrians. The park even plans to have rental bikes.Although mountain biking is illegal inside the park, there's good trail riding inside the surrounding National Forest.

Best place to road bike on the South Rim: Hermit Road
Until the greenway is completed, the best place to pedal on the South Rim remains Hermit Road. From mid-March through mid-October, the National Park Service bans most private vehicles from this paved, canyon-side road, which travels eight miles west from Grand Canyon Village to Hermit's Rest. Here, cyclists can pedal peacefully, interrupted only by a handful of private vehicles and buses (to which they must yield), and a smattering of pedestrians. In addition to providing access to crowded overlooks, the road skirts the rim in places, so you can absorb some nice views without stopping. After passing through miles of pinyon-juniper woodland, the ride ends at historic Hermit's Rest, near the Hermit Trailhead.

Best place to road bike on the North Rim: Entrance Road
On the North Rim, the park's entrance road is wide enough for cyclists who are unfazed by the sometimes-heavy traffic. The highways outside the park undulate through miles of ponderosa pine and spruce-fir forest, and they make for good riding. One road on the North Rim is not recommended: The Cape Royal Road. Though scenic, this narrow, winding road has poor sightlines and may be dangerous for cyclists.

Best Mountain Biking on the South Rim: Arizona Trail near Grandview Point
More than 20 miles of gently rolling single track, including stretches atop a rocky spine known as the Coconino Rim, begin 1.3 miles outside the park, in the Kaibab National Forest near Grandview Point. Except for a few steep, rocky sections, the trail is suitable for intermediate level riders. There's more good peddling in the forest just outside the park's main entrance, near Tusayan, where the Forest Service has marked three loops of varying size. These marked loops travel at least partly on old jeep trails, beneath towering pines. Unfortunately, they're within earshot of Tusayan's busy airport.

Best place Mountain Biking on the North Rim: Forest roads through the Kaibab National Forest
The Kaibab National Forest on the North Rim offers great mountain biking on little-used National Forest roads and the Arizona Trail. Some of these roads, which can become very slick in wet weather, lead to canyon overlooks where camping is permitted (and free). A good Forest Service map is a must for these rides, which have few signs and can feel mazelike in places.