All Joan Denizot wanted to do was lose weight. The best way she could think of to do it was ride a bike. But she couldn't find a bike for someone her size — not in a bike shop or on the Internet.

The 48-year-old from Fairfax, Vt., who was looking for a bike that would handle 300 to 500 pounds, endured twinges of humiliation getting sized up by svelte bike-shop employees.

She was never satisfied with the answers she got about structural limitations of bikes. The most manufacturers would tell her was that their bicycles were good to about 200 pounds.

Frustrated after months of looking, she was struck with an idea — and Super Sized Cycles was born.

"Hey, I'm not the only fat person who wants to ride a bike," Denizot said.

Operating exclusively on the Internet on a shoestring budget, Denizot started to sell bicycles in April. A former professional chef, landlord and mother of four, Denizot is new to Internet marketing and new to bike manufacturing.

That doesn't necessarily matter, she said. She finally has a way to exercise that doesn't seem like pure drudgery, and a business that will help others.

"It's one more reason I'm excited about it, because it can make a difference for people," Denizot said.

On her quest to start her company, she met a bike builder from Arizona, Chris Zanotti, in an online forum for bike builders. He was game to design a bike for her, and was inspired by the idea of a tandem, a bicycle built to hold two people.

He had no idea whether he'd be able to find the parts he envisioned needing, but that was nothing new.

"I work in aerospace and race-car design, and you are always coming up with stuff that does not exist yet. You've got to find a way to make it work," Zanotti said.

He started with the type of steel tubing used in tandem bikes and used super-strong welding material known as super-missile wire, used more commonly in aerospace welding. He added disc brakes more typically found on downhill racing mountain bikes and the biggest-volume tires he could find.

The frame was designed with a low center of gravity to make it more stable and easier to get on.

"We want to have them feel very relaxed and very in control, because they are not looking for performance, they are looking for control," Zanotti said. The bike was named A New Leaf.

Denizot also found a bike builder already making heavy-duty bikes in New York City. Worksman Cycles builds the Newsboy and Newsgirl models that look like the cruiser bikes ridden by kids in the 1950s with chrome fenders, upright handlebars and coaster brakes.

Denizot worked with the builders to make the Newsboy and Newsgirl extra sturdy, selecting puncture-resistant tires and a comfortable gel seat. She also carries tricycles made by Worksman. More models are on the way, including a modified recumbent bike that will feature a wide seat.

Super Sized bikes cost from $476 for the Newsboy and Newsgirl, which can handle up to 330 pounds, to $1,749.99 for A New Leaf, which can carry 550 pounds. Denizot's also added electricassist bikes that start at $629.99.

Sales have been in the neighborhood of two bikes a month. Denizot has been impressed by the reach she's had on the Internet. Bikes have sold in Alaska, Hawai'i and the Carolinas. She's counting on word of mouth in those places to build sales.

Denizot underwent gastric bypass surgery a year ago, and has lost and kept off 100 pounds. She's delighted to have a way to exercise.

"What's fun about this bike is I get on and I feel like a kid again," she said.