Hellwig Products Co. Inc. was built more than 70 years ago on a spring.

Specifically, the helper spring that father and son Rudy and Don Hellwig envisioned in the mid-1940s to improve the suspensions of passenger cars that commonly had sagging rear ends from the weight of passengers, items stuffed into trunks and the weight of campers and tow vehicles.

The Hellwigs came up with the idea for their Spring Stabilizer in 1944 while working for a business installing heavier stabilizer springs to replace the weaker leaf stabilizer springs that came factory-installed in ‘40s-era cars. But a shortage of steel during World War II prevented them from manufacturing the springs until late 1946.

Once they started manufacturing the springs in their Glendale shop, father and son began selling them to car shops on the weekend as well as visiting neighborhoods to look for cars with sagging rear ends and offering to install their springs so they could ride level again.

What made the Hellwig product unique was that instead of having to take off the tires and wheels and the entire leaf spring assemblies on cars, their spring could be installed around the existing springs, which is why the father and son sold their products for just $7, which included installing them in people’s garages and driveways.

Once the business started taking off, Rudy and Don Hellwig relocated to the Visalia area in 1967 and opened up a larger factory east of the city, where the company remains.

Of course, things have changed in the 50 years since the Hellwigs moved here. The original factory has expanded to 70,000 square feet on a 50-acre parcel and employs 48 workers.

Today, Hellwig’s bread and butter is still vehicle-suspension products, manufacturing about 700 varieties of helper springs, air suspension systems and sway bars sold across the U.S. and around the world.

A major part of Hellwig’s business is selling after-market suspension products, but some of its products are sold as production parts for clients that include Oshkosh Defense, which manufactures tactical vehicles for the U.S. military.

Despite having a worldwide market, all Hellwig products are made in Visalia, and Melanie White, the company’s vice president and granddaughter of Don Hellwig, said there are no plans to relocate to a larger, urban area.

“We still believe Visalia is a great place to manufacture,” because of its central location in California, proximity to Highway 99 and a good work force, she said.