Tim Kelley has always been an engineer.

First, it was building hot rods in high school. Then, his career involved designing Disney roller coasters.

He’s now retired, but the Mount Vernon resident isn’t done.

“I cannot sit still,” said Kelley, who doesn’t wish to share his age.

So he now focuses his efforts on creating bicycles for people with disabilities.

Two years ago, he made himself a bicycle with two wheels in the front and one in the back, for added stability, and an electric assistance motor.

Then he created another for his neighbor with a spinal-cord injury.

“He’s happy if he’s out in the garage tinkering,” Kelley’s wife, Sara, said, noting he has made eight bikes in total.

A single bike takes Kelley six months to finish, and each one is custom-made except for the tires. Some bikes have seats that swivel and lock into place, so riders can safely transfer from their wheelchairs. Others have a hand-rowing mechanism for riders paralyzed from the waist down who cannot pedal. A few have electric assistance motors, and others are lightweight and ideal for competitive racing.

Kelley has even made two child-sized bikes for his two grandchildren, Jack and Rylie.

And all the bikes fold flat for easy storage.

Kelley meets with every client to discuss necessary features, then sizes and tailors the bike to fit the person over the course of its creation.

“It’s a little like putting on a suit,” he said about the minute adjustments he makes to each custom bicycle.

Without ever earning a college degree, Kelley worked for Disney as an “imagineer,” helping to design one-of-a-kind amusement rides from 1967 to 1989.

Walt Disney, Kelley said, surrounded himself with outstanding talent.

“Getting to know those people was the real treasure of it all,” he said.

Only two of the roughly 20 engineers had college degrees when he first started the job.

Despite the glamour of his title as “imagineer,” Kelley said riding roller coasters as part of his job was not his favorite.

“I don’t like really tall stuff,” Kelley said. Rather, rides such as Peter Pan in Disneyland and Soarin’ in Disney World, which have a lot of interesting visuals and special effects, are Kelley’s favorites.

Now, his interests are setting up a proper business for his custom bicycles.

Last semester, Kelley applied to the University of Iowa Pappajohn Entrepreneurial Center and was matched up with two undergraduate students in an entrepreneurial business consulting class. The students conducted research studies and helped Kelley set up Facebook and YouTube pages for his business.

One of the students, UI senior Matthew Heiser, said the consulting was his first experience in a business setting.

“[Kelley] let us know about his background in engineering,” Heiser said. “What he’s able to do just by himself … I’d never seen anything like it before.”

The bikes with electric assistance motors can reach speeds of more than 15 mph and are like “a treadmill going down the road,” because riders can propel themselves up to a high speed before starting to row for exercise, Kelley said.

“That’s the payback,” he said, leaning back in his chair, a content smile on his face. “Watching them go down the street, grin on their face, wind in their hair.”