TRW’s North American (NA) Aftermarket Group has announced the launch of a coil spring program. With an initial offering of 303 SKUs, the program covers 90 percent of the North American coil spring aftermarket, and includes parts for Chevy Avalanche; Chrysler 300; Dodge Ram; Ford E/F150; Ford Focus; Honda Accord; Jeep Liberty and Nissan Pathfinder, among others.

Brian Rassin, product group manager, TRW Aftermarket North America, explained, “As a vital part of a vehicle’s suspension system, all TRW branded coil springs are manufactured to exacting OE standards. Storing energy, coil springs are situated in the part of the suspension system that supports the weight of the vehicle. Fitting a replacement spring that has different characteristics to the OE specification can not only destroy the ride and handling characteristics of a vehicle, but can also negatively affect braking performance. Worn springs can affect a vehicle’s braking performance by up to 5 percent and a broken spring can puncture a tire causing a blowout which can lead to an accident.”

Operating in a harsh environment, coil springs need to be strong and durable, says TRW. Road debris thrown up by the tires can strike suspension components and result in damage to the protective surface coating of the spring. Coil spring rate (strength) is defined by wire diameter, the number of coils, the coil spring body diameter and material specification. The vehicle manufacturers’ drive to reduce component weight has resulted in high stress coil springs with relatively few coils.

“As a leader in active and passive safety technology ZF TRW employs the very latest design and manufacturing methodology and testing; coils are shot peened for improved fatigue life and all finished product is cycle and load tested to ensure consistent quality for long-life operation,” said Rassin. “In addition, we powder-coat the coil springs to maximize corrosion resistance and for improved overall appearance.”