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Suspension Bushing Science

The most important suspension upgrade you keep forgetting about

Aaron Bonk
Jul 11, 2017

Additional photos by Prothane

Changing up your car's timeworn suspension bushings will never be glamorous work. The original ones'll do everything they can to keep you from getting them out and, even once they've been replaced, nobody'll ever know about it but you. Look past those crusty lower control arm bushings that haven't been touched for two decades, though, and you're only limiting how well your car could handle. For more on why those bushings are so important and what to do when they fail, we looked to Prothane's Tom Smisek, who walked us through the least-glamorous part of your car's suspension you'd be a loon not to address.


Sooner or later, those OEM rubber bushings of yours will be toast. According to Smisek, you'll know it when handling gets sloppy and the ride gets rough; leave all of this unaddressed and it'll only get worse. "They tend to rot away due to exposure to the elements and petroleum-based products," Smisek goes on to say about what exactly causes those original bushings of yours to fall apart. The climate, road debris, and time all contribute to their demise.

"Prothane's specially formulated urethane is more durable and impervious to gas, oil, and grease for long bushing life," he says. Unlike rubber bushings that are designed to be soft but at the expense of some sponginess, urethane's stiffer and results in better handling, more control, and increased performance from the suspension upgrades you've already made. The best part is that bushings like those from Prothane are direct replacements for the factory pieces, which means installation's so easy even you can do it.

  |   Unlike OEM rubber bushings that are meant to be soft and compliant, urethane bushings like those from Prothane are stiffer and result in better handling, more control, and a firmer ride.


You already know poor handling can be an indicator of worn-out suspension bushings. According to Smisek, periodic inspections underneath your ride ought to be made in order to check bushing condition. Specifically, he says, you're looking for slop, cracks, or any obvious deterioration. Checking all of this out once a year will never be a bad idea. But nobody says you have to wait for those factory bushings to fall apart. "Most enthusiasts don't wait for rubber failure," Smisek says about those who are looking for a firmer suspension and better handling now.

  |   Upgrading those factory rubber bushings to urethane will never be a bad idea, but if you're waiting for those original ones to wear out first, look for signs of slop, cracks, or any obvious deterioration.
  |   Suspension Bushings Science Worn Bushings
  |   Suspension Bushings Science Worn Bushings
  |   Obvious signs of bushing wear include cracks, deteriorated rubber, and an overall sloppy-handling suspension. All of this can lead to poor handling, deteriorated ride quality, and, in some cases, an unsafe condition.


You can replace those cracked-up and deteriorated bushings with original equipment right from the dealer or you can put something stiffer into place that'll yield a firmer, more stable ride, something longer-lasting, and something that'll result in better handling. Any time a car's suspension has been modified or if any sort of track days are in the future, Smisek recommends urethane over rubber. "Increasing engine and drivetrain performance requires a suspension system that can handle the additional torque and cornering stress, and rubber bushings are not designed for that kind of high-performance driving," he says.

As far as your suspension's bushings go, stiffer means a more immediate response when doing things like cornering or even when accelerating or braking. Go too stiff, though, and you'll experience a harsh ride and a whole lot of noise. Urethane is the best compromise between the rubber bushings the factory says you need and the solid, race track-only spherical joints you think you want. "Prothane offers Total Kits for all popular cars," Smisek says. "These are complete kits of matched components that replace the rubber bushings." They're even available in red, which is about as glamorous as you're gonna get when it comes to one of the best suspension upgrades you'll be the only one to know about.

  |   Upgrading those suspension bushings of yours might be one of the most important upgrades you'll likely be the only to ever know about. Get yours in red, though, and make sure you're not the only one who knows you did it.


Costa Mesa, CA 92626
By Aaron Bonk
415 Articles



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