Earlier this summer a customer entered Edgartown Bicycles with a very stylish bell on her bicycle.

“Where did you get it?” said Frank Jennings, owner of the shop.

Minah Worley couldn’t remember where she had purchased the bell, so Mr. Jennings helped her out with its origins.

Secrets of success: domestic assembly, attractive aesthetics, practicality. — Courtesy Clint Slone

“My stepson made your bell,” he said.

Mr. Jennings’s stepson is Clint Slone, co-founder, with his brother Nick Slone, of Spurcycle, a San Francisco based bicycle accessory company. As chance would have it, Ms. Worley had pedaled right into the bell creator’s original place of employment.

Clint Slone’s education in high-end bicycle parts began when he was seven years old. That’s when he moved to Martha’s Vineyard, in 1988, and his stepfather, a former bicycle racer, opened Edgartown Bicycles as a high-end bike shop.

“I would move the bikes outside and sweep the floors and shake the rugs every morning on my bike ride to the Edgartown elementary school,” said Mr. Slone. “When I got a little older my brother and I ran the rental department during the summer.”

Mr. Slone attended the Martha’s Vineyard Regional High School, and then Stanford University. He credits his high school education with helping him gain admission to Stanford’s product design program.

“Paul Brissette, who recently retired, and Chris Baer, who still teaches at the high school, helped me structure an independent study so that I could focus on product design,” said Mr. Slone. “I think one of the main reasons why I got into Stanford was because of some of the classes I got to take, like Imagineering and AutoCAD classes that allowed me to build a portfolio of work around product design. It showed that I was actively doing it, and was motivated.”

He tinkered outside of school, too. “My best friend Alan Lovewell and I spent most weekends inventing and making little things,” he said.

After graduating from Stanford, he began working as a product design consultant for medical and consumer product companies. He worked on an aspirator for children, a knee implant for osteoarthritis and various stent designs for health care startups. But he remained passionate about cycling, and after about eight years of design consulting, he and his brother Nick decided to apply their creative brainpower to bicycle accessory design.

“That’s what we were most passionate about, and it felt like a return to our roots,” said Mr. Slone.

Spurcycles has sold 25,000 bells to date. — Courtesy Clint Slone

In 2012, the siblings founded Spurcycle, and hit the market with a pair of high performance bicycle grips. A successful Kickstarter campaign allowed them to launch their bell the following year.

“We had a $25,000 goal and we raised $330,000,” said Mr. Slone. “We showed the making of the bell which gave it a sense of authenticity which I think resonated with the Kickstarter community.”

Spurcycle’s bell resonated with consumers, too, both literally and figuratively. To date, the Slones have sold about 25,000 bells. Raw bells are priced at $39 and coated black bells at $49.

“We originally set out to design a $25 bell, but when all was said and done our costs were way too high for us to make it here in the U.S. and use expensive stainless steel materials for the construction. We priced it so we could still make money. Luckily people have been okay with that,” said Mr. Slone.

Mr. Slone attributes the bell’s early success to its domestic assembly process, attractive aesthetic and practicality.

“People are disconnected from how things are made these days because hardly anybody works in manufacturing in the U.S. anymore,” said Mr. Slone. “I think showing that we are responsible for sourcing the bell’s parts from different states is something people like to see and support.”

The Slones live in San Francisco and regularly commute by bike over the Golden Gate Bridge to Sausalito, where they now have an office. “Tourists and bicycles share the same lane so that sort of inspired us to design the bell. If you’re on a road bike and you need to get the attention of a vehicle driver a bell is useful. But in the past, there was never a bell that was desirable to put on a performance bicycle,” said Mr. Slone.

The Spurcycle bell is a practical safety device that suits the sleek design aesthetic of a high performance bicycle. Its dome has thicker walls and is more compact than most bells. It is also hit harder to produce a louder and longer lasting ring.

“We use about the same amount of metal as regular bells but we shrunk it down and compressed it,” said Mr. Slone.

Tour de France competitor Lars Boom shared a photograph on Twitter that featured a black Spurcycle bell on his ride. “If a tour rider doing training rides, sees value in a bell and is putting it on a $10,000 performance bicycle, that is a good sign that it is a trend that will likely keep growing,” said Mr. Slone.

In fact, imitation bells have already started appearing on the market, and Mr. Slone predicts that Spurcycle will soon have competition. “Established companies with plenty of research and development money to spend are going to jump in the same game if they see us selling 60,000 bells — our goal for next year,” said Mr. Slone.

Mr. Slone returns to the Island as often as he can, which is usually every other summer.

“I try to be there the last week in August when all of my other friends come back too,” he said. “We watch fireworks and enjoy some good beach time.”

In the meantime, he has Sausalito. “I like it because it reminds me of Edgartown. It’s a touristy harbor town,” he said.