Other armies may snicker, but the Swiss army is preparing to re-equip its unique cycling troops with modern fighting bikes.

In a $6.3 million deal, modern machines will replace the trusty "metal mules" introduced in 1905, enabling Switzerland's three bicycle regiments to ride into battle in the 1990s and beyond.Military bicycles provide transport for 3,300 Swiss soldiers stationed in the plain between Lake Constance and Lake Geneva.

"Bicycles are quick and quiet," said Army spokesman Col. J. Peter Flueckiger. "A truck or a car makes noise that you can hear from afar, especially at night."

Troops on bikes can also roll at short notice across tough terrain, operate without fuel, and spread out quickly, making them a difficult target for aircraft, he said.

Other armies may use bicycles for messengers or routine patrols, but Switzerland is believed to be the only country to use them as an integral part of defense strategy.

Three prototypes, made by three Swiss firms, meet the tough army standards and are about to undergo field tests. They must have two gears, carry at least 330 pounds, weigh around 48 pounds and cost less than $900.

Soldiers in bicycle regiments keep their vehicles and guns at home, ready to roll out in an emergency. Even though fully equipped troops carry around 175 pounds of equipment, the army says they are quicker to mobilize than motorized troops over distances up to 25 miles.

An army handbook said bike-mounted and motorized troops work together.

"The motorized troops follow the bicycle troops, leaping from cover to cover, but overtaking the bicycle riders should be avoided for technical and psychological reasons," it says.

Most of the 500 soldiers who join the bike troops each year are volunteers, many of them top athletes whose conditioning helps them to meet the physical demands of their duty.

"You are proud to be a part of the troops," Flueckiger said. "If you come to active duty without training, you are not going to make it."

Fully laden bicycle soldiers have to pedal as much as 125 miles a day during training, he said, and must leave the regiments when they turn 32.

"You still see lots of people in their 50s and 60s who have their old military bikes that they ride to work or to their gardens," said Flueckiger.