AROUND THE WORLD ON HOT AIR & TWO WHEELS. By Malcolm Forbes. Simon and Schuster. 271 pp. $24.95.

HERE COMES MALCOLM Forbes roaring into his chateau at the head of a pack of black-leather- suited bikers wearing "CAPITALIST TOOLS" colors and hell bent for fois gras. There goes Malcolm Forbes in a whoosh of propane, heaven bent in a hot air balloon the shape -- and approximate size -- of the chateau. Bon voyage, monsieur! Oo la la, I ope monsieur does not break ze neck.

A reporter once asked Forbes for the secret of his success. His answer was memorable: "Hard work, imagination, perseverance and a father who left me $100 million dollars." Malcolm Forbes is a guiltless, happy man, and to judge from this book, a coffee- table adventure book written with a half dozen or so of his bike-and-balloon companions, very good company on the road and in the air. There is something winning about a hugely rich man who is at peace with himself and humanity and who likes to have fun on the grand scale.

He owns, aside from Forbes magazine and the chateau in Normandy, estates more or less all over the world, including an island in Fiji; a DC-9; a yacht large enough to invade the Falklands with; a huge private collection of works by Faberg,e (known principally for the eggs he designed for the czars), and 30 motorcycles. He picked up that particular bug when he was 48 and promptly became an enthusiast. Make that, Enthusiast. This book is perhaps the only place you will find it argued that motorcycles increase your life expectancy. Forbes is probably the only person who can make it sound convincing.

Sometime later he picked up ballooning, in a big way, characteristically, since Forbes does not do things in a small way. Described and photographed here are his trips across America, through Europe, Russia, China, the Middle and Far East.

He likes "firsts." In 1973 he became the first man to cross this country by hot air. It took just over a month. He landed, somewhat ingloriously, with his son in the freezing water of Chesapeake Bay. Two years later he almost became the first to cross from California to Europe by helium. It was a grand undertaking. One reads the account of the nearly disastrous launch with gratitude that the mission foundered on the tarmac and not at 40,000 feet.

THAT STILL left the problem of what there was left to do first, so he set his sights on leading a motorcycle caravan of his friends through the Soviet Union. It had never been done, for the simple reason that the Soviet Union had never permitted it to be done. So he made the first of many calls to the estimable Armand Hammer, chairman of Occidental Petroleum and chum of Leonid Brezhnev, and the thing was done, faster than you can say "The capitalists will ight among themselves for the privilege of selling us the rope with which to hang them."

In the Soviet Union the "Tools" -- as they call themselves -- encountered the usual lies, bugged hotel rooms, body odor, slow service and paeans to Stalin. The one bright spot came when their motorcycle tour-paks were jimmied open and robbed in Red Square in broad daylight while they were inside the Kremlin admiring the Faberg,es. Having made a tally, Forbes' son Bob announced. "I'm afraid they've got us by one egg, Dad."

Another call to Hammer produced a China opening. No one had ever ballooned and motorcycled there. "Firstness is always fun," says Forbes, "and it's the one record that no one else can break." But there the Tools were presented with a dilemma: their consummately gracious Chinese hosts would not allow the balloon, emblazoned with FORBES MAGAZINE HAILS CHINA-U.S. FRIENDSHIP, to fly free. It was all right to float it above the stadium, but it had to be tethered. Free-flying balloons carrying Americans weren't covered in the Shanghai Communique.

Forbes, however, contrived the tether to "slip," and off he went, to the great consternation of Mr. Chen, the guide. He landed not far away in the middle of an artillery base, where he was greeted not as an incoming bomb but as a welcome curiosity. Lest Mr. Chen be sent off to be reeducated, Forbes explained his action in a toast that night to the minister of Sport and Culture: "It wasn't to be naughty or unfriendly. It was to demonstrate the sport of ballooning. A balloon is not meant to be tied down. It's part of the wind. It's a beautiful thing to see -- if you're not with the security section of the Ministry of Foreign Affairs."

As one who can claim to have helped introduce the Frisbee to China two years after President Nixon's first visit, I sympathize with Forbes about the value of this kind of diplomacy. Balloons are inherently friendly. That wouldn't stop the Soviets from shooting one down, of course, but to most of the world they are objects of gaiety and pleasure, borne gracefully and silently by the wind. "There isn't anybody who doesn't love a balloon," says one of the gang over the French countryside, waving back at the children who have come out to see the extraordinary thing above. The crowds that came out to see the yellow sphinx over Cairo, the 240-foot high replica of Pakistan's independence monument, and the giant elephant over Thailand must have sensed that a nation capable of producing a man of such gestures is friendly and decent and good-willed, and Forbes is to be congratulated for that as well as for having produced such a delightful book.