Are Struts Part of Suspension? Understanding Their Role

Yes, struts are a critical component of a vehicle's suspension system. In fact, they serve a dual purpose: they support the vehicle's weight and dampen road vibrations, essentially combining the functions of a shock absorber and a structural support in one unit. To fully understand how struts fit into the suspension, it helps to break down what the suspension does and where struts come into play.

What Is the Suspension System?

The suspension system is the network of parts that connects your vehicle's wheels to its frame. Its primary jobs are:

• Absorbing bumps and road irregularities for a smooth ride.
• Keeping tires in contact with the road for traction and control.
• Supporting the vehicle's weight and maintaining proper ride height.

Key components include springs, shock absorbers, control arms, sway bars, and—yes—struts. While many cars use a combination of shocks and springs, struts are commonly found in the front suspension of front-wheel-drive vehicles and are becoming more common in rear applications as well.

What Exactly Are Struts?

A strut is a structural component that integrates the coil spring and shock absorber into a single assembly. Unlike a shock absorber, which only dampens motion, a strut also acts as a load-bearing part of the suspension. It provides structural support for the vehicle's weight and helps maintain wheel alignment.

How Struts Differ from Shocks

Many drivers confuse struts with shock absorbers. The main difference:

• Shock absorbers work alongside springs but do not support weight—they only control spring oscillations.
• Struts replace the upper control arm and serve as a pivot point for the steering system in many vehicles. They also support the vehicle's weight directly.

If your car has struts, you'll often see a large coil spring wrapped around the shock portion. If it has shocks, you'll typically find separate springs and shocks mounted independently.

Why Struts Are Considered Part of the Suspension

Struts are absolutely part of the suspension because they perform essential suspension functions:

1. Weight support: They bear the load of the vehicle's corner.
2. Damping: They control the rate of spring compression and rebound.
3. Alignment: They provide structural points for camber and caster adjustments.
4. Steering: In many front suspensions, the strut houses the steering knuckle.

If you remove the struts, the vehicle cannot support its own weight or steer securely. That's why they are a fundamental suspension element.

Types of Struts in Modern Vehicles

McPherson Strut

The most common type, used in millions of front-wheel-drive cars. It combines a shock absorber, coil spring, and steering knuckle into one assembly. This design saves space and reduces weight.

Strut Assembly vs. Shock and Spring

Some vehicles use a shock and spring combo instead of a strut. For example, many trucks have separate shocks and leaf springs. However, if your car's service manual refers to a "strut," it's a single unit that must be replaced as a whole.

Signs Your Struts Are Failing

Worn struts affect ride quality and safety. Look for:

• Excessive bouncing after hitting a bump.
• Nose diving when braking.
• Uneven tire wear.
• Fluid leaks around the strut housing.
• Knocking or clunking noises from the suspension.
• Poor handling, especially in corners.

If you notice these, have your struts inspected. Most manufacturers recommend replacing struts every 50,000 to 100,000 miles, but it varies by vehicle and driving conditions.

Can You Drive with Bad Struts?

Technically yes, but it's unsafe. Bad struts increase stopping distance, reduce steering response, and can cause loss of control. They also accelerate wear on tires and other suspension components.

Replacing Struts: What to Know

Replacing struts is not a simple DIY job for most people because the coil spring is under high tension. It requires a spring compressor and specialized tools. However, many shops offer "quick struts"—pre-assembled units that are safer and easier to install.

When replacing, it's standard to replace struts in pairs (both fronts or both rears) to maintain balanced handling. An alignment is always required afterward.

Practical Recommendation

If your car has struts, check them at every tire rotation. Watch for the symptoms listed above. When it's time to replace, choose quality parts from reputable manufacturers (like Monroe, KYB, or Bilstein) and have a professional install them. Budget around $300–$800 per axle for parts and labor, depending on the vehicle. Proper struts are not just a comfort item—they are essential for safe driving. Don't delay replacement if you suspect wear.