MOLARS grinding, incisors bared, nostrils flaming, eye sockets flared - I grabbed the small, black safety bar and held on for dear life."Save your strength," said Paul Ruben, roller coaster expert, historian, and fellow occupant of seat one, "Psyclone.We'll be moving soon." For those bogged down by headlines of faraway wars, Soviet collapse, the rise of a new world order, Mr. Ruben has this summer's first, real news scoop: Woodies are back. Forget the ersatz, high-tech whine of polyurethane on tubular tracks. Forget looping upside down, harnessed like a plow horse. Forget easy, steel rides that "glide" and "soar." America is moving back to good vibrations, jackhammer style. Back to the nails-on-blackboard screech of steel wheels on steel track. Back to good ol' fashioned fake-outs like low-hanging cross-beams, the menacing creaks of flexing timber, the portending doom of overstressed lug nuts. With names like "Predator" (Darien Lake, N.Y.), "Thunder Run" (Louisville), and "Texas Giant" (Arlington, Texas), new wooden roller coasters are putting the sounds of "pockety-pockety-jig, jiggedy jiggedy pock" back in the middle of the midway. Besides these three which opened last season, the world's tallest and fastest, "Mean Streak," opened June 7 in Sandusky, Ohio. "Wildcat a once-famous ride in Kansas City - was just reassembled in Frontier City, Okla. The "Giant Dipper" in San Diego is back as a National Historic Landmark after a 13-year hiatus. And the list goes on. "Roller coaster purists have always preferred the joys of wood," says Ruben, hearkening back to the 1920s, when 1,500 coasters dotted the American landscape like giant-matchstick pleasure-domes. The Depression, lack of maintenance, rising land values, and World War II all contributed to the roller coasters' demise, says Ruben, former editor of RollerCoaster! Magazine, and the man most often named as America's leading authority on roller coasters. The number of woodies bottomed out two years ago at a mere 77, he says. Now, armed with state-of-the-art computers, new technology, preservation fervor, and new demand, the new woodies are higher, faster, stronger, wilder. Here at Six Flags Magic Mountain, Ruben has been riding the all-wood "Psyclone," which opened in May as an exact replica of the original Cyclone at Coney Island in Brooklyn, N.Y. He has been rating the same features that he has rated on 300 coasters worldwide: positive/negative "Gs" (gravity), side-thrust, dull spots, white-knuckle quotients (surprise turns), and air-time (time spent lifted off one's seat). "If I had one roller coaster ride to take before I stop for good, it would be this one," said Ruben after a dozen trips divided among front, middle, and back cars. Because of year-round accessibility and the nation's second highest number of roller coasters (20, compared to Ohio's 21) California is the roller coaster capital of the world, says Ruben. "Psyclone" is a classic twister which weaves through its own structure with banked, disguised turns. A much taller and longer wooden ride here is the Colossus, known as an "out-and-back" coaster, with higher, faster drops, gentle curves, but no surprises. Based on unrelenting ferocity beginning to end, "Psyclone" gets Ruben's highest rating. "There's no time to regain composure," he said. Cedar Point Amusement Park in Sandusky already had nine roller coasters, including the world's tallest and fastest (the 205-foot "Magnum XL-200," with a top speed of 72 m.p.h.) when it added its "Mean Streak" this month. "We thought, how can we top Magnum?" says Barbara Colnar, park spokeswoman. "But people kept telling us to build another woodie. They want the noise, disorientation, and danger factor they can't get from steel coasters." Part of that disorientation is what Ruben calls the picket-fence effect, the quick-fire sound and sight of support beams placed close to the track to heighten a sense of danger and speed. "A roller coaster doesn't have to be massive to give a great thrill," he says. "People look at this ride and say, 'no big deal' because it looks so wimpy," says Wendy Winman, manager of San Diego's "Giant Dipper," just restored with 25 percent new wood, all new bolts and new track. "Then they get off saying 'whooooooa! Sharing the new "Psyclone" ride here a few times with Ruben, one can digest a few tidbits of coasterdom's pretzel logic. Rougher rides are in the back car, "like a benevolent mugging," he says. Middle cars are for the coaster timid. The front seat provides the most negative Gs, i.e. liftoff, holding patrons in place only by the lap bar. "When you ride a coaster, it will take control and you have to make your peace with that," Ruben says. Some people can't do that, he adds. Those who tighten muscles and resist come off the ride drained and physically tired; those who relax come off exhilarated. Greg Bauman, a founding member of American Coaster Enthusiasts, says woodies are best because they stretch and give, are warmer to sight and feel, and ripen with age. Expansion and contraction of wood can make the ride feel different each time. Unlike the new steel generation, woodies aren't built for turning people upside down in loops, corkscrews, and boomerangs. This widens appeal to both younger and older patrons, he says. Pressed for the down side of woodies, Bauman says some gained notoriety in their old age for providing brutal jolts to the uninitiated. The "Wildcat," a coaster that burned six years ago in Youngstown, Ohio, "left people with battered ribs if they were foolish enough to ride with their hands in the air," he says. New fin braking systems, individual lap bars, better cushioned seats, and computer-designed tracks have done away with many of the hazards of older coasters. Peter Irish, spokesman for the International Association of Amusement Parks and Attractions, says his association keeps no safety statistics for roller coasters alone. But the Consumer Product Safety Commission (CPSC) catalogs injuries with a nationwide electronic surveillance system in hospital emergency rooms. The CPSC places amusement parks among the 10 safest activities in America: two reported injuries per 100,000 visitors compared to 253 per 100,000 bicyclists, 224 per 100,000 baseball players, and 134 per 100,000 injured by doors. Also found more hazardous than amusement parks: billiards, rollerskating, basketball, and stairs. "This coaster has an uncanny resemblance to the [Coney Island] Cyclone in every curve," says Ruben. The original was built in 1927 for about $100,000. Sixty years later, the price of the new Psyclone is $5 million. "This takes you back to when roller coasters were young."