Tuning the chassis can solve the handling mystery

Jan. 1, 2020

Just as tuning your customer's engine can make a dramatic impact on performance, so too can tuning the chassis. As an analogy, you could compare a car to a professional boxer. The level of conditioning needed to win in the arena is not merely power a

Steve Temple

Custom Bay chassis tuning Hotchkis Performance suspension handling improving suspension Just as tuning your customer's engine can make a dramatic impact on performance, so too can tuning the chassis. As an analogy, you could compare a car to a professional boxer. The level of conditioning needed to win in the arena is not merely power and speed — you also need agility and endurance. In automotive terms, that would involve properly setting up the suspension.

That's particularly true on older vehicles, in which the handling left a lot to be desired even when new from the factory. Part of that was due to the state of automotive technology at the time of manufacture, along with other factors such as keeping costs down and keeping ride comfy. Hence control arms that were made of stamped steel and cushioned with soft rubber bushings. The result was a car that was both affordable and comfortable, but swayed like a punch-drunk boxer with weak legs.

And the factory stock suspension is no match for today's grippy radial tires and bigger horsepower numbers available from current-technology engines.

Beefing up the suspension is a reasonable and effective project because it doesn't alter the looks (except for a slight lowering in most cases). For example, we took a close look at the Hotchkis Total Vehicle System (TVS). For maximum effectiveness, it's important that chassis mods not be piecemeal. Simply adding a bigger swaybar or different coil springs doesn't take into account other factors like the camber curve or caster angle. Hence the need for an integrated system and overall strategy, particularly with older cars.

That's why Hotchkis developed tubular control arms, among other suspension components, with significant differences in both material and design. The front arms not only are stronger and lighter for less deflection and to reduce unsprung weight, but also have a taller spindle to maintain negative camber. They also are adjustable for precision chassis tuning.

Custom-calibrated Bilstein shocks provide better damping of the upgraded suspension, and the lower control arms in the rear are now boxed for greater rigidity and to provide an attachment point for a rear swaybar. To reduce body roll, Hotchkis added stiffer, large-diameter swaybars with a hollow configuration.

The result is a classy car that preserves its classic looks, but works far better, with a greatly improved level of comfort for street and freeway driving and markedly better cornering ability.

These changes improve balance, steering response, stability and safety, but don't require modifications to the chassis. This means customers can make the most of their car's punchy performance.

Steve Temple is a freelance technical writer and photographer with more than 25 years' experience. He has served as director of sales and marketing for Shelby American and as online editor for major magazines like Hot Rod, Car Craft and Rod & Custom.