How to Tell If Your Shocks or Struts Are Bad
It’s difficult to know just when it’s time to replace shocks and struts. For one, they go bad slowly, so the reduced ride comfort and road control you’re getting don’t seem out of the ordinary.
Also, there’s no set time or mileage for when aging shocks or struts are due for replacement. You won’t find a set service interval in your owner’s manual.
Third, these parts can be hard to get at, and seeing precisely how worn they are requires expensive disassembly. That’s just not practical or cost-effective.
Bad shocks and struts are diagnosed through other methods. Here’s what to look for as telltales:
- Cupping on tires, especially if a rotation was performed on schedule but abnormal wear is still occurring.
- Suspension bushings problems—cracking, peeling, off-center.
- Active leaking of oil on parts.
- A rougher ride.
- Bottoming out (your vehicle’s body or suspension hitting the ground) when going up a parking garage ramp or backing out of a driveway.
- Longer stopping distance.
- Swaying after a turn or lane change or in cross winds.
- Noticeable bounciness (more than one or two bounces) after going over dips or bumps.
- Nose-diving when you apply the brakes.
What Do Shocks & Struts Do?
Shocks and struts in good condition help your car handle whatever comes at you on the road—bumps, debris, sudden stops, swerving, potholes, wind gusts or sharp turns. They control the side-to-side, front-to-back and up-and-down shifts of the car’s weight and maintain optimal tire contact with the road.
Shocks or struts are hard-working parts. They can go through 75 million cycles over the course of 50,000 miles. Even on well-paved roads, they can move up or down 1,500 to 1,900 times every mile. They are partners with the brakes, steering, suspension, tires and electronic safety systems—anti-lock brakes, stability control and crash avoidance systems—in keeping a vehicle traveling safely on the road. They:
- Maintain tires’ good contact with the road by preventing them from moving up and down too much.
- Contribute to stability as you accelerate, stop and turn.
- Add to ride comfort by absorbing jolts and bumpiness from irregular road surfaces.
- Control a vehicle’s body movement (side-to-side roll, bouncing).
- Help the tread wear evenly for longer tire life.
They don’t help support the vehicle’s weight or any loads, contrary to what many think. The springs do that. But having worn-out shocks or struts creates more work for the springs as well as other important suspension parts. Without the control that a good shock or strut provides, these other parts get overworked, causing fatigue and premature wear.
Shocks and Struts Aren’t Just About a Smooth Ride
Today’s vehicles have highly engineered electronic safety systems: vehicle stability systems, ABS (anti-lock brakes), traction control, collision prevention control and automated braking. These all work together to keep tires in proper contact with the road and provide the most stability.
When you have an unexpected hard stop or swerve, your vehicle's crash avoidance systems send instant electronic signals to the brakes and other critical components. If ride control parts like shocks and struts are worn, they may not properly respond.
Then the crash prevention systems can’t function as designed and you have less control behind the wheel. Stopping distance increases and brakes and tires wear more quickly. There’s added strain on the springs, which have much more up-and-down and side-to-side action to control.
How Long Do They Last?
It all depends on the amount of wear and tear they get, and that depends on the quality of roads you drive, if you haul loads and how aggressive you are behind the wheel. That’s why periodic inspections are important.
Have a technician check every 12,000 miles, if you get an alignment, when you get new tires, at least once a year and whenever you notice the symptoms above. (Les Schwab Tires typically does visual inspections each time tires get rotated and during pre-trip safety checks.)
You may not notice your ride control has been compromised when these parts are wearing out, because it happens gradually. But shock absorber or strut failures aren’t just bad for comfort. Replacing them when it’s time keeps your auto’s electronic systems and suspension working as they should, extending your vehicle’s life—and keeping you safer on the road.