It is midnight in Columbus, Ohio, and Pinky's Palace is circling the fairground so the Phantom of Balance can say hi to Tarzan Zerbini. The Phantom is at the wheel. He has played this fairground before, but he cannot remember where the entrance is, and neither can his younger sister, who is pretty sure she has also played Columbus, except maybe that was Columbus, Ga.

"Aha," says the Phantom. He has found an unlocked gate. He swings Pinky's Palace, which was a Trailways bus in its former life, in toward the trucks where Tarzan is sleeping.

"Tarzan has lions and tig=rs," explains the Phantom's wife, peering out the bus windows into the darkness. That is really why they are here tonight, of course. This is not just a roadside social call. The Phantom of Balance, who makes his living by cavorting on trapezes and whirling wheels dizzingly high above circus floors, has decided to expand into lions and tigers.

"It's a daredevil thing in the circus business," he says admiringly, speaking of animal trainers. "Everybody looks up to a wild animal trainer and says, 'Gee, he's brave.'"

His wife nods, as if to say: a new challenge, you see. The man is restless.

As it stands now, their lives are not entirely without excitement she is The Glamorous Jeanette Williams, trainer of spirited Arabian and Lippizan stallions, granddaughter of a German horse trainer, daughter of a multilingual circus performer who died when his chariot flipped mid-race. Every time the Ringling Bros. and Barnum & Bailey Circus performs, she stands in the center ring, wearing a glittering white costume and enormous feathery plumes, surrounded by horses that snort and stamp their hooves. She shouts, waves her arms, cracks her whip; the horses rear up, dance, kick big red and yellow balls high into the air.

And he is Elvin Bale, trapeze artist and all around daredevil, great-grandson of an English juggler, grandson of a lop-de-lop circus bicycler, son of a tiger trainer.He scrambles, blindfolded, around the outside of a huge revolving wheel. He rides a motorcycle across a tightrope while his twin sister Nita dangles beneath him by one foot.

He shakes a white cape dramatically from his bare shoulders, climbs hand over hand up a rope to a lone trapeze above the center ring, kicks out high into the air with the energetic delight of a child on a swing, and then dives forward toward the concrete and scares everybody to death. He catches himself by his heels. He does not use a net. Evel Knievel shook his hand last year in New York and told him he was crazy.

"I like to thrill people," Elvin Bale says simply.

They cruise from show to show in a fully carpeted bus (blue for the front room, cream for the bedrooms) named after Jeanette Williams' daughter Pinky, who was born before Jeanette divorced Gunther Gebel-Williams, the animal trainer who travels with the circus' other unit. The bus has a dishwasher, trash compactor and electric can opener; a washing machine and dryer; built-in digital wall blocks; and a wet bar that floats mysteriously up out of a counter at the touch of a switch.

The side of the bus says, "Elvin Bales," in script, and they have a private joke about that, called, Who's Elvin Bale? Bale and Williams watch from inside as people walk by and read the name. The people read it again, looking puzzled. Then they look up toward the tinted windows, where they cannot see two faces peeking at them, and they mouth, "Who's Elvin Bale?" SOmeday, of course, everybody will know.

In the circus arena they are blonde and gorgeous, with powerful bodies and dazzling smiles. Up close they are even more blonde and gorgeous. It is a little disconcerting. People keep calling him the Robert Redford of the circus. He drives in bluejeans and a V-neck sweater, dropping cassettes into the tape deck, singing. She sleeps late on the road, sits on the couch watching the color television, cooks dinner, sings along with him.

They rarely stay in one place very long. "After a certain period of time you just can't stand it," says Bale. "You havea to move."

Just now they are enroute to Washington, having just finished a stint in Cincinnati, and Bale is deliberating over the size of tiger cages as he drives. His 23-year-old sister, Bonnie, is riding with him; she has been riding horses at the Ringling Bros. and Barnum & Bailey Circus World in Orlando, Fla., but now she is changing her act too, learning trapeze. The neck spin hurts, but she is working at it. "Mummy told me to start by holding for a count of one," says Bonnie Bale.

Mummy should know. When she married Trevor Bale back in England (he had been doing bicycle tricks on stage; she was in the same cabaret, singing, "I'm shooting high, got my eye on a star in the sky"), she had to learn all the thongs his mummy had done, like bareback riding in a tutu and a feathered headband. "She also learned to hang by her teeth," says Bale.

They have all got it in their blood, this terror of sameness, this love of applause. They are performers. Their parents were performers. Trevor Bale watched the boy Elvin and coaxed, bellowed, threatened: "Of course you can do it," he would cry, watching his son miss a trick; and then, losing his patience, "I dunno what's the matter with you bloody kids. You've been in the circus since you were born and you can't do a bloody thing."

Elvin Bale flew, which is circus language for sailing through the air from a trapeze, when he was 5 years old. First, performed at 12. Drove fast cars through Sarasota, Fla., where his family moved when Trevor Bale joined the Ringling Bros. winter headquarters; hung out with Frankie the horseback somesaulter and Angelo the juggler. His high school offered a class in circus. He is 30 now and has never been away from the circus in his life.

"It's a wonderful feeling," he says. He is talking about hanging upside down, but also about his special place in the floodlight. "Sometimes when I have a cold I go on the trapeze and it makes the cold go away."

Jeanette Williams hid from the elephants and played hopscotch in the circus stable when she was 4. Grew up on traveling wagons, to the brilliant lights and noisy music of the German Circus Althoff. She was 9 when her father died. Her mother ran the circus pretty much alone, and sent the young Jeanette off to boarding school, where she learned business and heard circus voices in her dreams and suffered. "I don't think my mother ever realized how much," Williams says. "I loved the circus so much."

She came back at 18 and got horses to train, "six little, horrible, disgusting, disrespectful shetland ponies." She pronounces it "chetland," the German accent still noticeable, and chortles at the memory of those ponies that would not behave. Her grandfather would have cried, "Hundskruppel!" - crippled dogs! - and stalked out of the ring, his moustache working in rage. But Williams was young and wanted desperately to be in the ring, under the lights. She trained ponies to step to the whip, stallions to rear in formation, cockatoos to ride bicycles over the tightropes.

And over the years, the two circus kids each had their little diversions, of course: Williams riding a tiger through the streets of downtown Hamburg, for example, Bale beating an elephant off his twin sister on an Atlantic City pier. Williams clutching a wooden tent pole during a tornado in a small town in Bavaria, watching the black funnel cloud careen under one side of the tend and out the other. Bale hanging upside down from a trapeze bar in Canada, suddenly aware that his white tights are stuck to the metal and he will have to come down without them, which he does, as the organist energetically plays "The Stripper."

"My father said, 'Get back up and finish the act,'" says Bale wincing.

They have also played for royalty. "The King of Belgium," muses Williams over her breakfast eggs at a Pennsylvania truckstop."And Holland, and Sweden. ANd Carlos of Spain."

"I was invited to perform a command performance for the QUeen of England," says Bale. "And I played for Prince Rainier." He is the proudest of the Monaco performance. The Prince likes circuses, and Elvin Bale was awarded the 1976 Golden Clown, which no younger performer has ever won before. The clown is about a foot tall, and very heavy. The Bales keep it on the floor of the bus while they travel, so it will not break anything.

They are stars now, but it is not quite enough. The circus does not promote them the way it promotes Michu the midget, who has his own dool, or Gunther the animal trainer, who is on the advertisements and serving plates. "They sell 12 little postcards in a packet," says bale, "and I've got one little picture in there. I've got to check all the time to see if it's in."

Right, says Williams. Audiences don't understand how hard they work, how long it takes to make 12 stallions rear simultaneously (a thing completely foreign to their nature; horses normally rear only while fighting or mating), how dangerous Bale's crazy trapeze act really is.People are so cynical now. A man could high-dive into a drinking glass and it would not impress them.

"Television has ruined it," says Bale. "They see people jumping out of windows and getting shot and coming out without a scratch." He mourns for the days of his grandfather, when a bicycling acrobat and a couple of trained dogs brought down the house. "Now you have to almost break your neck to get them to go 'Wow,' or applaud, or anything."

They have threatened to leave Ringling Bros. to join a smaller production called the Circus Vargas, where Elvin Bale would be top banana. "I'm a ham," he says cheerfully. "That's my business. I'd like to go on television and have people come up to me and say, 'Gee, I saw you on television, and you were terrific.'"

Bales pays for breakfast and walks back to the truckstop, whistling.He says he once thought of being a lawyer, or a politician. "I'd like to be somebody," he says. "That's why I put my name on the coach. Everybody wants to be somebody."

He climbs aboard and waits for his wife. She appears in the doorway and says a truckdriver stopped her as she was leaving the restaurant, wanting to know, please Ma'am, who's Elvin Bale? "I said, a circus performer," Williams says. "Aerial work. Trapeze."

Bale hoots and slaps the steering wheel. "That's one more!" he cries. "One more knows." He pulls the bus out of the parking lot and begins to smile.