A strut is a structural suspension part that supports the car’s weight and includes a shock absorber, while a shock only dampens bouncing.
Strut
A structural part of the suspension that supports the vehicle’s weight, holds the spring and has a built-in shock absorber. It is part of the steering geometry.
Shock
A damper that controls spring movement and bounce. It doesn’t support weight.
Differences
- Struts are structural. Shocks aren’t.
- Struts need alignment after replacement. Shocks usually don’t.
- Struts cost more.
Cars
Many front-wheel-drive cars have struts in front. Trucks often use shocks.
Signs of wear
Bouncy ride, leaks, nose-dive when braking, uneven tires.
Lifespan
50,000 to 100,000 miles.
Replace
In pairs.
Cost
Shocks: $200 to $600. Struts: $400 to $1,000 per pair, plus labor.
What each part does
A shock absorber controls spring movement and bouncing by converting motion energy into heat in fluid. A strut combines the shock absorber with structural support, holding the spring and carrying vehicle weight.
Alignment
Replacing a strut changes the suspension geometry, so a wheel alignment is needed afterward. Shocks usually do not need an alignment.
Where they appear
Most modern front wheel drive cars use struts in the front, and rear shocks or struts depending on the design. Many trucks and SUVs use shocks along with control arms.
Symptoms of wear
- Excess bouncing after bumps.
- Nose dive when braking.
- Body roll in turns.
- Uneven or cupped tire wear.
- Clunking or knocking noises.
- Oil leaking from the shock body.
- Longer stopping distances.
Bounce test
Push down hard on a corner of the car and release. If it bounces more than 1 to 2 times, the shock or strut may be worn.
Life expectancy
Shocks and struts commonly last 50,000 to 100,000 miles, depending on road conditions and driving style.
Replace in pairs
Replace them in pairs on the same axle to keep handling even.
Cost
Parts and labor typically range from about 450 to 1,100 dollars per axle for struts, and less for simple shocks, depending on the car. A quote from a shop will confirm the price.
Safety
Worn suspension components lengthen braking distance and reduce control, especially in emergencies.
Mechanics and symptoms
A shock absorber is a damper that controls spring movement and does not carry vehicle weight, while a strut is a structural part of the suspension that supports weight, holds the spring and affects steering and alignment. Many modern front wheel drive cars use MacPherson struts in front and shocks in the rear. Signs of wear include a bouncy or floating ride, nose diving when braking, uneven tire wear (cupping), fluid leaking on the unit and clunking over bumps. A bounce test, pushing down hard on a corner of the car and releasing, should see the car settle after one or two bounces. Shocks and struts typically last about 50,000 to 100,000 miles, depending on conditions.
Cost and replacement tips
Replacing a pair of struts commonly costs 500 to 1,500 USD installed, and a pair of shocks costs about 200 to 700 USD. Replace them in pairs on the same axle to keep handling balanced, and get a wheel alignment afterwards, which costs about 100 to 200 USD. Worn dampers lengthen braking distance, with one test by a tire manufacturer finding that worn shocks added a noticeable distance to stops from 50 mph. Using the correct part for your model matters, as struts and shocks are not interchangeable. Take the car to a certified technician if the car pulls, shakes or has a vibration at speed.
Based on data from AAA and vehicle manufacturer service information
