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.
Shock and Strut Service and Repair FAQ
The Basics on Shocks & Struts
What do shocks and struts do?
Shocks and struts help the tires maintain traction, by keeping the car from bouncing or the tires from losing contact with the road when you hit a bump or apply the brakes. As part of the suspension system, they help control car motion and keep the weight of your vehicle balanced even around sharp curves, so you have better stability and a more comfortable ride.
A shock or a strut operates the same but mounts differently. Each of the four tires has either a shock or strut connected to that corner’s suspension and vehicle body or frame. These hydraulic cylinders provide motion damping by restricting fluid flow through a series of internal valves. As the wheel and suspension move up and down, the shock valving slows and stabilizes these movements.
How are shocks and struts related to control behind the wheel?
Shock absorber or strut failures can be a driving safety hazard. Along with tires, shocks and struts are key factors in ride control. Ride control is how well a car handles whatever comes at you on or off road—bumps, debris, sudden stops, swerving, potholes, wind gusts, sharp turns. The ability to control your vehicle is reduced when shocks and struts aren’t properly controlling the side-to-side, front-to-back, and up-and-down shifts of the car’s weight that come with everyday driving. This is an even larger concern when the road is slippery, wet or rough.
How do I know I need new shock absorbers or struts?
Shock absorbers and struts that are working well mean more stable driving in every condition. When these components are worn, you may notice a rougher ride, longer quick-stopping distance, nose-diving when you apply the brakes, dripping fluid, tires that are cupping, excessive bounce after a bump, or swaying after a turn or stop.
How often should I have shocks or struts checked?
Even on well-paved roads, shock absorbers or struts can move up or down 1,500 to 1,900 times every mile. Because handling performance tends to decrease gradually, a driver doesn’t always realize how much ride control has been lost. If you notice abnormal tire wear, or more vehicle movement than in the past when cornering, accelerating and stopping, pay Les Schwab a visit. It is a good idea to have your suspension checked on a regular basis, and when you get new tires.
Monotube, gas charged, foam cell—how do I know which shock is right for my vehicle?
With so many choices, selecting the proper shock can be confusing. Just stop by and we’ll give you our best advice, based on your vehicle and how and where you drive it.
Use our Store Locator to find the Les Schwab nearest you.
Lowering Suspension: Pros and Cons
Lowering your car or truck so it’s closer to the ground is a popular way to customize your ride. Done right, it’s a great look that also boosts handling performance. Done wrong, it could compromise handling, drivability and traction, reduce tire tread life and even damage parts.
Pluses and Minuses of Lowering Suspension
PROS CONS More road feel Reduced ride comfort Stiffer ride Impractical for rough roads Less roll when cornering Accelerated or uneven tire wear Better handling Chance of bottoming out Improved aerodynamics Potential rubbing on parts or tires Improved traction Can’t use a standard jack Less rollover risk Cost Great looks Warranty issues
More road feel. A lowered suspension helps a driver be highly attuned to how their vehicle acts on different pavement as more of the vibrations from imperfections in the road surface come through the steering wheel.
Stiffer ride. With this setup, you have to have more rigid springs so the front or back of your vehicle won’t bottom out over bumps or depressions. This is the driving experience many prefer, versus a cushier ride from, say, a luxury sedan.
Less lean in corners. The lean of a vehicle around a sharp turn is greatly reduced, because the shift of weight is less due to the lower center of gravity. The part of the vehicle on the outside of a turn stays more level with the inside. This lets a car settle more quickly into a turn and act more responsively.
Better handling. Another effect of being closer to the ground is improved responsiveness, more stability and grip at speed. Because lowering means getting stiffer springs, there is less weight transfer when you hit the gas or brake hard. This means you’ll enjoy faster acceleration and quicker stops.
Less air drag. Lowered vehicles are more aerodynamic. There’s less air hitting the wheels and tires (that are not streamlined shapes). This makes these cars faster. Some owners of low-stance vehicles also notice improved gas mileage. BUT, lowering a car too much will actually increase wind drag.
Less rollover risk. Lowered vehicles have a lower center of gravity, which decreases rollover risk when cornering.
Improved traction. Lowering generally means you’ll put a plus-sized tire and wheel package on the vehicle. Such tires have shorter sidewalls, a larger contact patch (that keeps more rubber in contact with the road) and less roll around corners.
Good looks. Cars and trucks that have been lowered with custom wheels are attention-getters. It’s a more aggressive and performance-oriented look that stands out in a crowd.
Less ride comfort. If you and your passengers are accustomed to a softer suspension that cushions impacts like bumps and potholes, you may think less of the ride comfort of a lower suspension. You may also notice increased road noise since you’re closer to the pavement.
No go on rough roads. The lower clearance will not be your friend on rutted, rocky, washboard and potholed roads.
Uneven or accelerated tire wear. Lowering changes the geometry of your wheel-tire fitment. If it’s done improperly, your car may have an alignment problem that results in premature or extreme wear patterns.
Bottoming out. Even an inch-and-a-half lower suspension can cause problems around corners, with slight potholes or on speed bumps. Traveling over the lip of a parking garage or starting up a driveway or ramp could cause the front of your vehicle to hit the pavement. Contact with the ground can cause serious damage to components underneath the car, like the exhaust system and oil pan.
If you ever need a tow truck, you may require a flatbed. Otherwise, there could be a problem with the back body of the vehicle dragging on the ground.
Potential rubbing on parts or tires. Poorly done or extreme lowering can cause suspension and steering parts to contact each other, the wheels or the tires. It could also cause tires to rub the body during turns or going over bumps.
Can’t use a standard jack. If you get a flat tire, you may find out at an inconvenient time that there’s not enough clearance to get the unit under the vehicle’s frame.
Cost. Quality components and keeping correct alignment can get pricey. The lower you go, the more chance you’ll need additional parts. For example, if coilovers (meaning coil spring over shock) are part of your new setup, you’re likely looking at an outlay of $1,000 or more.
Warranty issues. You should check both your owner’s manual and any manufacturer’s or aftermarket warranty to determine if 1) the manufacturer advises against lowering your car, or 2) if lowering your car will void or adversely affect any warranty coverage you currently have.
Know This Before You Modify Your Suspension
Here’s what to know before you go low.
- If it’s higher performance you’re after, you may need to lower a lot less than you think. It’s easy to miss the mark and actually make your suspension worse. To be sure that components like struts and springs can do the work of keeping tires at the right angles, get expert help.
- Don’t cut corners when it comes to shocks, struts or other components. You’re making changes to the structure and balance of your vehicle. You don’t want to risk failing parts.
- If you modify your vehicle in ways that aren’t road legal, your insurer may not pay a claim for damage. Talk to your agent before you customize your ride and ask if your premiums will go up or policy terms change.
- Installing extreme aftermarket wheel-tire setups or suspension changes can result in steering, suspension or drivetrain problems that won’t be covered by your vehicle warranty. Check to see if the modifications you’re planning will result in denied warranty claims BEFORE installation.
- Get an alignment after you lower to ensure best handling and tire life.
- Take care while you get accustomed to how your new setup performs. With the much stiffer suspension, your vehicle may steer a little differently and won’t absorb road shocks as well. A sudden hard brake or tight turn on a bumpy road could cause a loss of traction.
Any time you change your vehicle’s OE (original equipment) suspension, you should be sure that you're not creating a setup that is either unsafe or is going to cause problems with other car functions. Like with many aftermarket customizations, it’s about finding the right balance of safety, performance, looks, cost and drivability.