A bicycle-racer friend once told me that the best cyclists are the ones who can endure the most pain. Last spring, while pedaling up a seemingly endless stretch of mountain road, as steep as a respectable intermediate ski run, I began to understand what he meant. I slumped over the handlebars. My thighs burned. My lungs ached. The muscles in my neck and back knotted into a painful spasm.

 The cycling computer mounted on the handlebars -- which registers speed, elapsed time and distance - told me I had covered 85 miles of the 102-mile ride. Under most circumstances, that would have been welcome news, but this was no normal ride. This was the Assault on Mt. Mitchell, named by Bicycling magazine as one of the 10 toughest centuries (rides of 100 miles) in the United States, and at mile 85, things had just begun to get interesting.

 Mt. Mitchell, a 6,684-foot peak near the western border of North Carolina, is the highest mountain east of the Mississippi. The Assault leads cyclists from Spartanburg, SC., through 70 miles of rolling countryside to Marion, NC., where the real test of endurance begins. In the 32 miles from Marion to the finish line near the mountain's summit, the route gains 5,200 feet -- gradually at first, then relentlessly. At its worst, the grade tops 20 percent, and with the exception of a 500-foot descent at mile 90, every wretched foot of it tracks uphill.  (Note: the total rider up hill climb is 10,895 feet of vertical climbing.)

 For the first 70 miles I had hung back, conserving energy for the uphill grade.. Where possible, I had latched on to pacelines -- single-file packs of riders -- and pedaled in the slipstream of the cyclists in front of me to reduce my wind resistance. This had obliged me to take my pulls at the front, but I knew that riding in the pack improved a cyclist's efficiency by as much as 30 percent. Whenever the pacelines broke away from me, I eased back and took time to enjoy the rural scenery, wave to overall-clad farmers sitting roadside in lawn chairs and talk with other riders from states as far away as California. The conversation seemed always to drift back to the cumulative effects of such  a grueling event and the challenge of the final 30 miles.

 "Some people claim this is a race against the clock," said a 50-ish ride veteran from South Carolina, who pedaled beside me for a few miles. "But in my opinion, it's more of a race against death."

 Former Ironman Triathlete Victor Selenow, who placed in the top 10 in 1981, had told me that in some ways the Assault was harder than the Ironman, which includes a 2 1/2-mile swim, a 112-mile bicycle ride and a 26-mile marathon. "The Assault is relentless, and you're forced to work the same set of muscles all the way to the top," he said. "The Ironman is more diversifted, and you're not constantly taxing the same muscle groups."

 Another participant had offered this encouragement: "The last five miles look like a battlefield after a major skirmish. There are cyclists strewn along the road everywhere, grimacing and moaning."

 By my own reckoning, I probably would be one of them.

 I am not a fanatical endurance athlete. When I set out for the summit of Mt. Mitchell, it had been just a year since I traded in my cast-iron college 10-speed for a sleek racing bicycle and soon began logging anywhere from 75 to 150 miles a week. After five months of training, I completed my first century ride -- a relatively gentle route that explored the valleys of east Tennessee -- in less than six hours. The accomplishment sent mood-altering endorphins coursing through my bloodstream. Come spring, I was ready for another fix, and that's when Mitchell reared its spruce-covered head.

 I realized that it was one thing to cover 100 miles along the flats; it was another thing to cover the distance while scaling 6,000 feet. Yet I was determined to try. My goal was simple: I wanted to cross the finish line inside the 12-hour period organizers had established for the ride.

 The six cyclists who attempted the first Assault in 1975 had a similar goat in mind. The idea was born during a Friday-night bull session at the Bicycle Gallery, a Spartanburg bike shop. Scott Hoffmann - shop co-owner and later a president of the Spartanburg Freewheelers, the group that sponsors the ride -- and six of his buddies were sitting around drinking beers when Bill Carlisle posed the outrageous notion that it might be possible to pedal the 102 miles from Spartanburg to the summit of Mt. Mitchell in one day.

 After the chortles and guffaws died down, the boys bet Carlisle he couldn't do it. Nonetheless, they then started mapping out a route along the two-lane highways that stretched between the town and the mountain. And a few weeks later, Hoffmann, Cartisle and four fellow cyclists departed from Spartanburg bound for the top. Some 11 hours later, Carlisle and Tony Ferrara straggled into the parking area beneath Mitchell's summit. The others had crashed and burned along the way. Word of the feat spread, and the Following year there were a dozen riders. The next, two dozen. By the mid- '80s, the race was drawing contestants from throughout the United States and even Europe. Swedish National Team rider Bjorn Bachman set the surviving Assault record of five hours, 50 seconds in 1985.

 The event now ranks as one of the most popular century rides in the East. Last May, a record 1,753 riders massed at the starting line. This year's race is scheduled for May 20.

 I arrived at the Spartanburg town square at 6:20 a.m., as the first rays of dawn filtered through the trees. Temperatures hovered in the 60s, though they would climb into the 80s by midday. A storm front a few miles to the west had stalled, ensuring sunny skies.

 Spectators lined both sides of Church Street. A column of cyclists wearing brightly colored Lycra shorts and shirts spanned the width of the street and stretched for 200 yards behind the phalanx of police cruisers that would escort us out of town. Immediately behind the cruisers the more-competitive contestants -- men and women with beer-keg thighs and $1,500 Italian bicycles -- clipped into their pedals.

 I settled toward the back of the pack, hoping to avoid the breakneck pace of the leaders. Around me, hundreds of other recreational riders -- spindly-legged teen-agers, muscular middle-aged men, rock-hard women in their 30s -- straddled their bicycles. There were touring bicycles with food-laden panniers. There were shimmering, ultralight racing frames mounted with nothing more than a pump and water bottle. There were grit-caked mountain bikes with lugged tires. There were even a few vintage tanks -- similar to the one I had sold the year before -- which at 35 pounds exceed the weight of most racing bicycles by 10 pounds or more.           

 At 6:30 a.m., the police cars, with their lights flashing, began to roll, and the 14th annual Assault on Mt. Mitchell was under way.

 Along the first five miles out of town, the crush of bicycles packed the road from side to side. Elbows rubbed elbows, brakes shrieked, tires brushed tires, and occasionally, a cyclist would topple after colliding with the rider in front of him. There were frequently yelling for riders to "hold their line," meaning that they should maintain a straight course and avoid veering into the paths of approaching cyclists.

 By mile 19, as the pack began to thin, the route approached a stone bridge at the bottom of a long, steep hill, the site of the Assault's first casualty. As we streamed by, I spotted a rider sprawled on the pavement, howling incoherently. Blood drenched his face, and the area from his forehead to his chin was bloated from the impact. Three dismounted cyclists administered first-aid while they waited for an ambulance. I learned later from Hoffmann that the man had lost control when his bike, hit the lip at the entrance to the bridge, and he had fractured his skull when his head hit the bridge wall He wore no helmet.

 A mile beyond, we arrived at the first of the 13 water-and-refreshment stops along the route. Several tables brimmed with bananas, cookies and apples, and plastic garbage cans outfitted with spigots dispensed fresh water. I snatched a handful of oatmeal cookies and a cluster of bananas, shoved them into the rear pockets of my cycling jersey and pushed on.

 I had learned during my first century that keeping the body stoked with food is as essential as maintaining pressure in the tires. After a couple of hours of intense exertion, the body exhausts its store of fuel, and if it's not replenished constantly, you "bonk", cycling parlance for the condition that leaves a rider trembling and seeing spots, with barely enough strength to tumble into the grass, kick away his bicycle and lie gasping.

 On the other hand, a steady regimen of carbohydrates -- both quick-burn simple carbs in fruit juice and slow-burn complex carbs found in cookies, breads and bananas -- will keep the wheels turning. During the Assault, I ate constantly, consuming 18 bananas, four apples, two dozen oatmeal cookies, four high-energy bars (220 calories each), and one-and-one-half gallons of water spiked with a high-carbohydrate drink mix.

 By 11:30, I rolled into Marion, a small crossroads town of fast food eat-aries, gas stations and convenience stores. A few dozen cyclists had connected with support teams there, and they lolled in the shade eating picnic lunches. Several riders napped briefly under the trees. A steady stream of riders disappeared into a burger joint and emerged with sacks of fat-laden hamburgers and fries -- reputedly the worst fuel for the task. I contented myself with another bunch of bananas and 16 ounces of water and soon began pedaling toward the Appalachian spine looming in the distance.

 As I pulled away from the water stop at mile 68, Jeremy Corm, an 18-year-old racer from Greensboro, NC., had already triggered the checkered flag. Corm finished the ride in five hours and eight minutes.

 In terms of mileage, Marion marks completion of two-thirds of the Assault. But in terms of difficulty, it's barely the halfway point. "It takes most riders as long to complete the last 30 miles as it does to finish the first 70," Scott Hoffmann had told me. "Because of the climb, the Assault is actually more like a 140-mile ride than a century." If Hoffmann's estimate were correct, and if I had the stamina to make it to the top, I would cross the finish line at 4:30, after 10 hours in the saddle.

 Once out of Marion, I cruised easily up a gentle grade past tranquil Lake Tahoma at mile 79. Just beyond, I encountered the first tortuous uphill stretch, a three-mile grunt known as Haines Eyebrow. I immediately felt the drag of the slope, dropped into my lowest gear and hoped for the best.

 The smell of smoking brakes rose from automobiles fighting the downhill drag along State Route 80 as we struggled uphill, and the easy banter among cyclists that had filled the first 70 miles had been replaced by the sounds of grunting and gnashing gears. The only verbal exchanges, in fact, came when cyclists announced their position as they overtook slower riders. A few of the 400 cyclists who eventually would drop out of the ride had already accepted defeat. Some limped beside their bicycles. Others sat at roadside, rubbing cramping thighs.

 By mile 82, two miles up Haines Eyebrow, I engaged in my first mental battle. All the minor aches that had accompanied me for the first 70 miles suddenly seemed insufferable. My hands had gone numb from gripping the handlebars, and my butt had been chafed raw. My thighs and lungs began to burn. And it seemed that around every bend, the hill grew longer and steeper.

 Individually, those woes would have been tolerable; together, they became debilitating. And I suspected that they'd only get worse over the next 20 miles. I began to think about - actually to dwell on -- the pain, and I realized that all I had to do to make it stop was climb off the bike and quit.

 "When you start to climb you'll regret every cigarette you've ever smoked and every beer you've ever drunk," Don Kirby, a Bicycle Gallery employee who completed the ride in 1985, had told me. And he was right. I even felt a twinge of remorse for all the days I'd gone without training during the previous winter. 

I had decided to remain in the saddle for a half-hour more, no matter how much it hurts, yet I was moments from surrendering when something remarkable happened. During the last mile up Haines Eyebrow to where the route joins the Blue Ridge Parkway and the grades soften for a time to an average 6 percent, the pain, or my perception of it, began to dull.

 I'd heard about the trance-like state that settles over endurance athletes as they complete the last few miles of their events, yet I had never pushed myself far enough to experience it firsthand. But it was happening now. A detached feeling slowly replaced my fixation on the pain. There was my body, on autopilot, turning the cranks and fighting gravity. And there was my mind, off somewhere, watching.

 "Toward the end of the ride you get into that mental state where you move up into your head and you find your own rhythm," Victor Selenow had told me. "It's almost like being hypnotized. You settle into this spaced-out feeling."

 I focused on the cadence of spinning pedals, the steady buzz of the chain passing over the gears, the rhythm of my breathing, the woodlands sliding by. I noticed on my cycling computer that my speed had actually increased from 5 to 7 mph, and I began passing other cyclists. I overtook one rider, a man in his mid-20s who had left me in the dust earlier in the day. "You animal !" he grunted after me. Under the circumstances, I couldn't have imagined a more gracious compliment.

 The 12 miles along the parkway whirred by. I don't remember many specifics, except that I passed through some wonderfully cool, dark tunnels carved through the rock, and that there were several beautiful views of the far away valleys and surrounding peaks. The smell of balsam filled the air. I remember glimpsing the observation tower perched on the summit of Mitchell and realizing at that moment that I would reach it.

 And I recall the first mass cheering section at the entrance to Mt. Mitchell State Park at mile 97, where several hundred people stood urging us on. They applauded just as enthusiastically for the dozens of cyclists who now hobbled beside their bicycles and the legions of riders who, as predicted, lay crumpled beside the road. Many of them would advance no further.

 The remaining five miles ranked as the steepest of the ride, and as I cranked uphill, I reached into my pocket and drew out my last banana. Though two water stops remained, I feared that if I stopped I'd be unable to regain my concentration and would risk cramping, so I cranked past them.

 At 2:50 p.m., I reached the Mt. Mitchell parking area in a daze, and when a group of spectators shouted that the finish line lay just around the bend, I redoubled my effort and tried to sprint, but my legs splayed outward and I nearly toppled.

 Seconds later I rolled across the finish line, and a woman wedged an official race patch into my hand. I had completed the ride in eight hours, 21 minutes. I had logged the final 30 miles from Marion in 3 1/2 hours, 90 minutes less than Hoffmann's estimate, and placed 745th among 1,353 finishers.

 What followed was an hour of sheer bliss, while my mood surged under the influence of endorphins and before the onset of the paralysis and fatigue that would plague me for the next four days. I dropped my bicycle among dozens of others, limped to a refreshment table where ride organizers proffered giant meat boggles and cans of cold soda, and found a seat on a sunny hillside. I cheered the riders who continued to straggle across the finish line and swapped war stories with other riders seated around me. I spoke with a young mother who had finished the fide an hour earlier.

 "You know, this race is a lot like childbirth," she said, laughing. "It's the most agonizing pain you'll ever go through, but when it's over, all you remember are the good parts."

 She was right. An hour later, I piled into a Greyhound with 35 other riders for the long ride back to Spartanburg. It had been a scant four hours since I had confronted Haines Eyebrow, where I wanted to roll into the grass and die, but that already seemed like a distant memory.

Now, as the bus swayed through the hairpin bends, zipping downhill, I turned to the cyclist beside me. "When I come back next year ..." I began. But almost before I finished the sentence, I dropped off to sleep. It was the first sensible thing I'd done all day.