Whether you are looking for a challenge or a chance to chill, a biking holiday may be the answer. And more than 200 companies now offer two-wheel itineraries.

Tours may range from one-day, all-downhill excursions to luxurious and leisurely trips across Europe that break for museum hopping, shopping and gourmet noshing.Here is a sampling of companies that specialize in bicycle tours. Other good sources for outfitters can be found in magazines such as Bicycling, Escape and Outside. Unless otherwise noted, all prices are per person based on double occupancy.

- Placing an emphasis on intimate, culturally focused journeys, Butterfield & Robinson is among the leaders in biking tours. Its slick catalog details more than 30 itineraries that also include distinguished dining and lodging.

New for 1998 are two tours designed for the avid cycler, with distances between 50 and 80 miles per day. B&R's versions of the Tour de France and Giro d'Italia races are both eight-day tours. Land costs are $4,575 and $4,750, respectively. Or the casual cycler can sample Nova Scotia on a six-day tour. Cost is $1,895 for the easy tour that includes stays in lovely inns.

B&R also offers an impressive schedule of luxury walking tours. Call 800-678-1147. Access (http://www.butterfield.com) on the Internet.

- Euro-Bike Tours has been guiding riders for 25 years. Its 1998 catalog features more than a dozen tours scattered from Ireland to Austria. The 14-day Adventure in Eastern Europe begins in Munich, Germany and rolls east to Budapest, Hungary. Land cost is $3,185.

Or consider a 10-day tour of France's Provence, which features two nights' stay in a 15th-century chateau. Land cost is $2,495. The company also offers a good selection of walking tours. Call 800-321-6060. Access (http://www.eurobike.com).

- Mississippi's Natchez Trace is among specialties of Classic Adventures, which also offers biking tours in France, Italy, Greece and Ireland. A 10-day tour of Germany's Romantic Road in June is $2,589. Phone: 800-777-8090. Online: (http://www.travelsource.com/cycling/classic.html).

Other cycling experts include Gerhard's Bicycle Odysseys (503-223-2402); Roads Less Traveled (800-488-8483; (http://www.roadslesstraveled.com); Bike Vermont (800-257-2226; (http://www.bikevt.com); Bicycle Adventures (800-443-6060; (http://www.bicycleadventures.com); and Europeds (800-321-9552; (http://www.europeds.com).