WASHINGTON, DC -May 11: Kevin Keefe, 61, is retiring as one of the oldest bike couriers in the District of Columbia. He is photographed in downtown Washington, D.C. on May 11, 2011. (Photo by Marvin Joseph/The Washington Post) (Marvin Joseph/WASHINGTON POST)

Let me tell you a funny thing about the sinewy, Spandex speed demons who skitter past downtown gridlock like water bugs and treat the bicycle delivery of each legal brief with the urgency of an action hero ferrying secret nuclear codes to save the world from annihilation.

A lot of them are pretty gray. Their bones hurt, and their joints flare up.

“Arthritis in my thumbs,” says Kevin Keefe, wiggling both his thumbs at me.

Of course they hurt. He has been leaning on them for 25 years. “It’s just finally time to stop, I think,” Keefe said. “The business isn’t what it used to be.”

Keefe will make his final delivery Friday, then he’ll retire from his informal post as dean of the dwindling corps of D.C. bike messengers, just before he turns 59.

Kevin Keefe is retiring as one of the oldest bike couriers in the District of Columbia. (Marvin Joseph/WASHINGTON POST)

“He’s the oldest, right?” I asked a messenger resting at one of their perches on L Street.

“Ah, no. Scrooge has gotta be 60, 61? I’m 57,” the guy told me, pointing to his gray beard and rolling his eyes a bit. “A lot of us are old timers out here.” And soon enough they’ll be joining Keefe in retirement.

The twilight of the city’s once booming courier business is ironic and a little sad, because it comes amid a huge bicycle renaissance.

Bikes are everywhere in the District, zooming along those new bike lanes, being shared and locked in cool racks. They are carrying not just messengers and weekend warriors in neon Lycra, but also women in dresses and men in suits who put their briefcases in the front basket in a very European way, casual and matter of fact. It’s not sport; it’s simply locomotion.

“I can see it every time gas prices go up. The gas goes up, the bikes come out. You can really see it this time,” said Keefe, also known by his messenger number, 86. “I just hope some of them stay on those bikes after the gas comes back down.”

A lot of the messengers confess to being annoyed by the newbie bicyclists who clog the bike lanes. Even Keefe, who rarely loses his temper on his bike, admits to laughing at their cluelessness. Still, he says, “better to be morons on bikes than morons in cars.”

Keefe joined the bike messenger scrum in its pre-fax, pre-e-mail glory days, when there were about 400 of them downtown, and they could easily pull down $100 for a couple hours’ work. (Today, they might not even break $75 in a 10-hour day.)

Back then, Keefe was a Vietnam War veteran who was studying physics while working on satellite projects for NASA. But he did a little tuning out when he hopped on a bike — and the adrenaline rush was irresistible.

“I just couldn’t see myself sitting behind a desk or at a computer the rest of my life,” he told me.

In some ways, he’s a classic Washington wonk — the kind of guy who can say “Oman’s really changed since the last couple times I passed through,” or comment on laser technology in between bites of his veggie pizza. But he doesn’t own an iPod, smartphone, computer, car or house, and he doesn’t have kids.

When you talk to most bike messengers, there are always a few blanks they don’t fill in. They have street names like Scrooge, Fo, Gadget, Hood Ornament and Suave (pronounced “swah-vay,” the messenger tells me).

Their legends are retold on the benches of Farragut Park or outside Frankie’s Pizza on Vermont Avenue. Remember the header Tony pulled into a windshield at 14th and I? Or the time 86 slammed his new V-brake and went right over the handlebars, face-first into a panel truck?

They sneered at the guys wrapped in their suits going into the buildings they were skipping out of.

Then came the advent of e-mail and the dawn of the post-9/11 super-security age. Almost overnight, the demand for the derring-do of bike couriers evaporated.

Most of the dabblers, the hustlers and the students stripped off their Lycra and pads and handed in their walkie-talkies. The ones who remained were the hard cores, like Keefe.

And for them, the work has grown less heroic. Fewer FEC filings and legal briefs to be raced through three miles of gridlock to make a 5 p.m. deadline. More laundry, shoes and cellphones someone forgot in a meeting across town.

“Lunches, I hate delivering lunches,” said Peter Fernandez, a.k.a. Suave, 41, who also once delivered a giant turkey from a law firm to a homeless shelter.

Anthony Jones, 51, whose back is covered in scars from a windshield collision, will never forget the set of golf clubs he had to balance on his nimble little road bike.

“A huge bag of soccer balls,” another guy told me.

“An ice cream cake. On a really hot summer day,” Keefe said.

These are the stinkers that bring them down. Less messenger, more gopher.

Despite such humiliations, piled atop a quarter-century of veering drivers, crazy U-turns and car doors being opened at the wrong time, Keefe has extended his middle finger only three times.

Once he signs off as Quick Messenger Service’s number 86 for good, he’s not going to put the bike away.

Nah, he’s going to get on it and ride, ride, ride. Nova Scotia? Baja, perhaps? He’s going to go all over the place, he said. Only, no ice cream cake this time.

E-mail me at dvorakp@washpost.com.