For years, drivers on Dockton Road, beachgoers at Tramp Harbor and visitors to the Island have been delighted, or at least bemused, by a row of old exercise bikes that were left at Portage.

Across the street from the now-vacant Portage Store, the bikes curiously faced Tramp Harbor, as if beckoning someone to hop on and take a spin. The so-called Portage Bikes joined the ranks of Vashon’s quirky spots, along with the John Deere Pond, the Jesus Barn and the bike in the tree, and have been immortalized in vacation photos, Vashon-themed greeting cards and even in county Councilmember Joe McDermott’s Facebook cover photo.

But for the first time in recent memory, Portage has been empty of exercise equipment for about a month. And the circumstances surrounding the bikes’ disappearance — be it upset neighbors, a landowner tired of the clutter or scrap metal collectors looking for a few extra bucks  —  seem to be a mystery.

“I’m very sad,” said Kate Hunter, who has lived near Portage with her husband for more than 20 years. “I think it was the sweetest thing.”

Hunter said she made the Portage Bikes a regular stop whenever friends visited the Island.

“We called it the Tramp Harbor Athletic Club,” she said with a laugh.

Bruce Haulman, a Vashon historian and retired college professor who lives near Ellisport, said he too misses the bikes, which overlooked what he calls Pedal Beach.

“It’s part of the quirkiness of Vashon. I’m sad to see it disappear,” he said.

The eclectic mix of exercise equipment has morphed over the years. Some bicycles came and went, and every now and then an elliptical or rowing machine appeared. Some past photos show just a handful of bikes at the spot, while one snapshot shows as many as 16.

But those who drive past Portage often say they began to notice more significant changes about the bikes several months ago. The dumping increased, and the spot became crowded with junkier bicycles and other exercise equipment. Other trash appeared too, and someone even dropped off a couch.

“For a while there were so many, it kind of became a dumping grounds,” said Maria Pottinger, who lives nearby.

Then the trend seemed to reverse, some say, and the bikes and other equipment began to disappear. For a while there were a couple treadmills left, and then nothing.

Nadine Edelstein, a tile artist who lives at Portage, said she and some neighbors periodically cleared out the equipment when it began to pile up, always leaving the classic bikes with the thin, metal bars that the spot is best known for.

“We would get together and cull them out to keep it looking a little more tidy,” she said.

However, Edelstein said she’s not responsible for the total disappearance of the bikes. She thinks that perhaps the person who rented the apartment attached to the Portage Store for a time or a road crew working in the area mistakenly took the bikes, thinking they were doing the community a favor.

“It cold be just a very easy misunderstanding,” she said.

Jim Didricksen, a county roads supervisor based on Vashon, said Vashon’s road workers are familiar with the Island and he doesn’t think they would touch the bikes.

“It could have been a crew that came over (from off-Island) and did it, but it’s highly unlikely,” Didricksen said.

Other neighbors suspect the bikes were hauled off by someone collecting scrap metal.

“The price of scrap is up now more than usual,” said Lou Engels, who lives nearby and owns Engels Repair & Towing.

However, the most widely spread rumor is that the owner of the Portage Store building, which has been vacant since 2001, finally got tired of the bikes and cleared them out.

Pottinger, whose children sometimes played on the bikes while waiting for the school bus, called the rumor “completely hearsay,” but added that she wouldn’t blame the owner if it were true.

“My thought is if the person at the Portage Store owns that property, he can do what he wants with it,” she said.

According to the King County Department of Assessments, the strip of land where the bikes once sat is part of the parcel that includes the Portage Store building and is owned, along with the building, by a man named Brian Gordon.

The county lists Gordon’s address as a P.O. Box in Steamboat Springs, Colo., but neighbors say they believe he currently lives in Seattle, visits the Island now and then and could have tossed the bikes.

However, one man who was outside the Portage Store last week said he knows Gordon and doesn’t think he was the one who got rid of the bikes.

The man, who doesn’t live on Vashon and declined to give his name, said he recently bought a boat from Gordon. He said Gordon was a nice person and he doubted he would take the beloved bikes.

“I’m a pretty good judge of character,” he said.

The Beachcomber’s attempts to contact Gordon were unsuccessful.

Maggi McClure, who lives on Maury Island and heads the Vashon Sheepdog Classic, may hold one clue in the bikes’ disappearance. In mid-April, McClure said, she was driving on Dockton Road and saw a group of men load the last remaining treadmill into the back of a truck filled with scrap metal.

“It looked like people collecting scrap,” she said.

McClure, along with many others, says she hopes more bikes will eventually be dropped off at Portage. But she worries that the charm of the original, old-style bicycles may be lost forever.

“Exercise equipment has changed. Those great old basic exercise bikes don’t exist anymore,” she said. “Maybe they’re gone, unless someone has some hiding in a basement somewhere.”

Edelstein said she, too, would like to see the iconic bikes return, and is even holding on to one she could put there.

“I’m not putting it out there if somebody’s going to toss it,” she said. “I’m kind of waiting for things to come back to normal.”