AMONG the tens of thousands of fellow bicyclists with whom I’ve dodged countless potholes in the Five Boro Bike Tour, the 300-pound guy in neck to ankle pink spandex remains my favorite. Perched atop an old three-speed Schwinn, leaning Elmo-like over the handlebars and pumping those thick pink thighs, he led the fit and the fat, the silly and the serious, the breathing hard and the breathing harder up Sixth Avenue and into Central Park for no other reward than a free ride on the Staten Island ferry.

In signing up for the annual bike tour the first time in 2002, I figured I’d suck it up, show my wife and children that I still had it at 56, and then hang up my padded shorts forever. But even before I made it the 20 miles to Astoria I knew I’d be returning the following May. It was that satisfying. That full of joy. And I loved doing something for no good reason, no political statements to be made, no charities to support, no trophies to be won.

And so it was in 2003, 2004 and 2005, rain or shine, pink guy or not, out of shape or grossly out of shape, a great spring day in the city.

Last May, however, everything shifted like a derailleur with a mind of its own. As I was comfortably chugging my way through the first 20-odd miles, my left pedal fell off on Front Street in Brooklyn, a victim of rust and time and — please imagine my late father shaking his finger — my own lifelong irresponsibility about my possessions.

Circling back and glancing down at the lone pedal on the street, bicycles whizzing by right and left, I was already imagining the despairing walk over the Brooklyn Bridge and the even longer trudge all the way across town on Canal Street to the car parked near the West Side Highway.

I walked over to a marshal at Front and Washington Streets who glanced down at the pedal in my outstretched hand and uttered something akin to “Oh, man, you’re finished!” Only she didn’t say finished. Then, as an afterthought, she pointed behind her, north toward the river, mentioning a used bicycle shop. “It’s probably not open,” she shrugged.

But it was. And a nice-looking young guy with an earring and an inscrutable expression on his dark face took a look at me holding the pedal (60, white, Jewish, ponytail wiggling out of the back of his silly helmet), then glanced at my pathetic mountain bike with a milk crate lashed behind the seat, and, without word or change of expression, walked into the back of the small crowded shop.

Five minutes later, just when I concluded that he figured I wasn’t worth his time, he returned and, without smile or smirk, held up a used foot pedal arm he had found in the back room. He handed it to me with a ratchet and watched dispassionately as I failed once, twice, three times to loosen the nut before he reached down and wrested the ratchet from my aching palm, muscled off the rusted old arm and put the new old one on, wiping his hands with a cloth out of his back pocket while walking slowly over to the cash register.

Here it comes, I thought, reaching into my pocket for a credit card and preparing myself to pay the equivalent of a whole new bike for a rusty old arm. Please know that I would have gladly paid big plastic money I don’t have to avoid the long walk back to my car. So when he rang up $11 for the whole thing, five for the arm and six to put it on, I was rendered slack-jawed, not a pretty pose for a man my age in a bike helmet. I reached deeper into my pocket for a thin wad of cash, embarrassed into speechlessness that I only had a measly $10 to tip him for his kindness.

But I was back on the road, as happy as any 60-year-old can be on a bike with 20-something miles left to ride, a lot of it uphill. Another great day. Another free ride on the ferry back to Manhattan.

A year later, though, I’m still humbled thinking about the kindness of the young man at the Recycle-a-Bicycle shop. Frankly, it’s tempting to swing this reverie around into one of those tiring and overworked “New York gets a bum rap” endings or, worse, a shameless piety whereby the guy in the bike shop and I transcended our ethnic, racial and age differences and were “just New Yorkers” true and true.

But as T .S. Eliot occasionally whispers in my ear, “That is not it, at all."

On today’s Five Boro Bike Tour, I’m leaving behind my arrogant notions about a free ride. I’m on a mission of thanks to the universe and the enigmatic guy at the bike shop and even the man in pink spandex for my unlikely and undeserved good fortune at being alive and well enough to pedal 42 miles. And when it’s all over, I plan to drop off the bike — and a more substantial tip — at Recycle-a-Bicycle in the hope that a small part of my cosmic debt is paid.

Steven Lewis, a faculty member at Empire State College, is the author of the forthcoming “Fear and Loathing of Boca Raton: A Hippie’s Guide to the Second Sixties.”