What is a car suspension?

A vehicle suspension system plays a key role in comfort, handling, brake performance and safety. Whether you’re driving through Toronto’s pothole-filled streets or on the highway, your suspension system is constantly engaged to ensure your vehicle remains stable. Let's take a look:

What it does

• Keeps your vehicle’s tires in contact with the road.

• Absorbs bumps, shock from potholes and other unevenness

• Balances cabin comfort, vehicle handling and stability.

Main components

• Springs, shocks/dampers, struts.

• Control arms, bushings, ball joints.

• Anti-roll bars and links.

Signs of trouble

• Excessive bouncy ride or nose dives.

• Uneven tire wear.

• Clunks, squeaks, poor steering stability.

Quick checks

• Bounce tests.

• Visual leak and bushing inspections.

• Tire tread pattern assessment.

Parts and purpose: how suspensions balance comfort and control

The main purpose of a car suspension is to address a common issue: uneven road surfaces. The car suspension does this by absorbing road impacts to:

• Keep all four tires in contact with the road surface.

• Absorb energy from potholes, bumps and other uneven surfaces.

• Control movement during acceleration, cornering and braking.

Suspension cushions the blow you’d feel as your car moves over external forces, including speed bumps, potholes, small stones, and gravel, by working with other vehicle safety systems, like anti-lock braking systems (ABS), traction control systems and electronic stability control (ESC).

Without a car suspension, your vehicle would have no way of reducing vehicle sway or shock absorption. For example, if your tires lose contact with the road, even the smallest bump could cause you to lose complete control of your car.

Core components of a suspension system (springs, dampers, arms, bushings, bars, bearings)

A car’s suspension system combines both structural and motion-control components that work together to help contribute to a smooth and safe ride:

Structural and load-bearing components

Structural and load-bearing components include:

• Springs (coil, leaf, torsion): Springs store and rebound energy generated when your vehicle drives over an uneven surface. The spring will compress or extend depending on the force applied (compress on flat roads and extend on uneven roads).

• Control arms: Control arms help guide your steering wheel’s movement. They’re attached to the axle and the vehicle’s chassis. They function similarly to leaf springs by negating the external forces that the axle bears the brunt of.

• Ball joints and bearings: Ball joints and bearings act as pivot points for your wheels. They allow your car’s suspension and steering to move smoothly.

• Subframes: Subframes are only found in some vehicles. These secondary frames hold the suspension system in place, improving the vehicle’s structural integrity and streamlining potential repairs.

• Stabilizer (anti-roll bars): Anti-roll bars prevent the car’s body from rolling when driving on uneven roads or cornering. This bar is a metal rod that connects the left side and the right side of the car’s suspension system. When the suspension moves due to irregularities in the road, the anti-roll bar transfers energy to the opposite wheel.

Motion control components

• Motion control components that contribute to your car suspension include:

• Dampers/shock absorbers/struts: Shock absorbers, also known as dampers, are fluid or gas-filled reservoirs encased in a tube, located between the vehicle’s frame and its wheels. If a wheel goes over a dip in the road, the springs extend. The energy stored in the spring is then transferred to the shock absorber. From there, the energy is distributed to the piston rod and into the piston, which moves through the oil. Struts are simply a shock absorber and a spring.

• Bushings: These act as a cushion between suspension components to reduce noise, vibration and harshness for a smoother ride.

• Sway bar end links: Sway bars connect the stabilizer bar to the control arms, transmitting force that keeps the vehicle level at all times.

• Strut mounts/top hats: Strut mounts secure the struts to a vehicle’s frame, reducing vibrations in the cabin.

• Tie rods: Tie rods are part of the steering system. They connect to the wheels and work with the suspension system to keep your car in alignment.

Ultimately, these components work together to maintain proper alignment, absorb shock and ensure your tires maintain contact, even in unpredictable weather conditions like ice, snow and heavy rain, which is common across Canada.

Springs explained

One of the most important components of your car’s suspension system is its springs. Its job is to support the weight of your vehicle and absorb any impacts from the road’s surface to deliver a smooth and stable ride. There are several types of springs used in cars today:

Coil springs

Coil springs are among the most common types used in passenger vehicles, SUVs and crossovers. They’re compact, highly durable and come in two “rates.” The first are linear-rate springs, which are based on Hooke’s Law and offer uniform coil diameter and uniform coil spacing, for more predictable vehicle handling. Progressive-rate springs or variable-rate springs, have uneven spaces between each coil, offering a more comfortable ride and better control during hard cornering.

Leaf springs

Leaf springs, which are made out of multiple plates bound together by rebound clips, are connected to a solid axle. Leaf spring car suspensions are relatively cheap to manufacture and have a reputation for withstanding a lot of weight.

Torsion bars

Torsion bars are a type of rotational spring that absorbs impacts through their twisting design. They are durable and commonly found in off-road vehicles and some trucks.

Spring rate

Spring rates directly impact the quality of your ride. A softer spring will improve your comfort while driving, but body movements will be more persistent. A firmer spring force will enhance your vehicle control but offer a stiffer ride.

Spring condition

Worn-out or sagging springs can lead to several issues with your vehicle. Not only will they fail to provide a comfortable ride, but it’ll also throw your suspension system alignment off, leading to uneven tire wear, poor handling and reduced stability, especially when you’re braking or cornering.

Choosing the right spring

Heavy-duty vehicles, specifically those that tow and haul, require a stronger spring, as these will help prevent suspension sagging. Off-road vehicles can benefit from torsion bar suspension systems as they offer better shock absorption. Due to the added weight of battery packs, electric vehicles often require heavy-duty coil springs.

Shocks and struts

Shocks and struts control how your vehicle responds to bumps and other road imperfections:

Function and types

The shock absorbers, also known as dampers, are the next important part of any car suspension system. Absorbers are fluid or gas-filled reservoirs that are encased in a tube. They are located between the vehicle’s frame and its wheels. Typically, the upper mount of the absorber is attached to the vehicle’s frame and the lower mount is connected to its axle.

If a wheel goes over a dip in the road, the springs extend. When this happens, the energy stored in the spring is transferred to the shock absorber. From there, the energy is distributed to the piston rod and into the piston, which moves through the oil.

A strut is the name given to the spring and shock absorber. For example, a shock absorber wrapped in a leaf spring is called a strut.

Struts in modern vehicles

Most modern cars use a MacPherson strut, which has a spring, damper and steering knuckle. The strut mounts and bearings will impact how your steering and alignment feel. When worn out, they can cause vibrations in the car cabin and uneven tire wear.

Geometry 101: camber, caster, toe

Vehicle wheel alignment can be defined by its camber, caster and toe:

What each angle means and how geometry affects handling and wear

Take a look at the definitions of each angle:

• Camber: This is the inward and outward tilt of the wheels. A negative camber can improve your vehicle’s cornering grip, while a positive camber can reduce tire wear with the trade-off of decreasing your vehicle’s performance levels.

• Caster: The caster is the tilt of the steering axis. A positive caster will improve stability when driving straight.

• Toe: Toe describes whether the wheels are pointed inward or outward in relation to the centre of the vehicle. If this is off balance, it can lead to uneven tire wear and unstable handling.

Common layouts: pros and cons

Common suspension system layouts, along with their pros and cons, include:

Front suspension types

Front suspension systems, also known as independent suspensions, include:

• MacPherson strut: MacPherson strut car suspensions are one of the most common types of car suspensions seen today. They are lightweight, compact and relatively inexpensive due to their simple construction. They use two main components: coil springs and shock absorbers. They are used in many types of passenger cars, with the exception of sports cars and cars with wider wheels.

• Double-wishbone suspension: Double-wishbone car suspensions are a second type of independent car suspension. They are often found in luxury vehicles and they operate using two wishbone-shaped arms that hold the wheel in place. The wishbone arms are mounted between the frame and the wheel and then the coil springs absorb energy.

Rear suspension types

Rear suspension systems, also known as dependent suspensions, include:

• Leaf springs: Leaf spring car suspensions are a type of dependent car suspension. This type of suspension is made out of multiple plates bound together by rebound clips and connected to a solid axle.

• Trailing arm: Trailing arm car suspensions help to control the vehicle so that it absorbs forces on all sides. The trailing control arms are attached to the axle and the vehicle’s chassis. They function similarly to leaf springs in that they negate the external forces that the axle bears the brunt of.

• Multi-link car suspension: Multi-link car suspensions are a newer version of the double-wishbone car suspension. It uses three or more lateral arms and at least one vertical arm, all of which can be angled in the direction of your choice. This leads to improved ride comfort, stability and handling.

Advanced and active systems

Modern cars feature advanced and active suspensions that use hydraulics, electronics and sensors to adjust how the suspension acts to improve comfort and stability. Here's what you need to know:

Electronic and semi-active damping

Electronic and semi-active damping systems can do the following:

• Electronic and semi-active suspensions: These systems use sensors and electronically controlled valves to adjust a vehicle’s shock absorbers in real-time. By doing so, drivers will experience a smooth ride over bumps and improved handling/stability.

The main benefit of these systems is how comfortable they make the ride and the improved performance levels compared to traditional fixed dampers.

Fully active and air suspensions

Here’s more information on fully active suspensions and air suspension systems:

• Hydraulic active systems: A hydraulic active suspension system uses sensors, electronics and hydraulic fluid to manage vehicle movement in real-time (wheels, axles, frame and chassis). Rather than reacting to bumps on the road like a standard suspension system, these help keep the vehicle flatter by counteracting body roll and pitch changes, for a smoother, steadier ride.

• Air suspension system: Air ride suspensions are found in luxury vehicles and sometimes larger work vehicles, such as diesel trucks or 18-wheelers. They function by replacing traditional coil springs with air springs made of rubber and inflated air. The car suspension itself features an air compressor, electronic controls and sensors.

While these systems offer advanced driving experiences, they are more expensive to manufacture due to how complex repairs can be. If you own a vehicle with either of these suspension systems, you’ll need to perform more maintenance on your car, especially during the winter months, as hydraulic fluid can thicken at cold temperatures, which can reduce performance levels.

EV-specific considerations

Unlike traditional gas vehicles, electric cars have unique suspension requirements due to their heavier vehicle weight. The added weight from the battery reduces the car’s centre of gravity, which improves stability, but also increases stress on the suspension parts, like the shocks, struts and springs. Because of this, regular maintenance is required to ensure your vehicle doesn’t run into any suspension trouble.

Further, electric vehicles use regenerative braking, which can change how the vehicle’s weight shifts when the car is decelerating. With the right suspension system, it can prevent the front end of the car from nose-diving while keeping the tires in contact with the road surface, which keeps the vehicle stable, but also ensures that both front wheels and rear wheel tires wear evenly.

SUVs and trucks: towing/hauling

Towing and hauling heavy loads can put additional strain on a vehicle’s suspension system, which is why load management and suspension upgrades can help reduce wear and ensure safe handling:

Load management

When the rear part of a vehicle is heavier compared to the front, the vehicle can sag, which impacts braking and steering stability by causing the front end to lift, which is a safety hazard. To prevent wear on your vehicle, proper load management and routine inspections are key.

Towing-specific upgrades and safety

Beyond this, vehicle owners can also upgrade their suspension system with aftermarket components that can reduce strain, improve safety and enhance towing stability. Common upgrades include:

• Anti-sway bars.

• Heavy-duty shock absorbers.

• Upgraded bushings.

• Reinforced Control arms.

Canadian road realities

Driving in Canada is not for the weak. With rugged, diverse terrain and unpredictable road and weather conditions, travelling in the wintertime can put strain on your car’s suspension system.

Rough terrain and road surfaces

Potholes, cracked pavement, gravel roadways and frost heaves are all common during the winter months in Canada. Repeated impacts on your suspension can accelerate the wear and tear on your shock absorbers, springs, bushings and control arms.

Winter damage and corrosion

Travelling in the winter can add another layer of stress to your vehicle suspension, as road salt and liquid brine can increase the rate of corrosion on metal components on the control arms, sway bars, bolts and car frame. Over time, the corrosion will weaken the suspension components, making repairs and replacements more expensive if not maintained correctly.

Seasonal performance changes

Cold weather conditions can thicken the hydraulic fluid, making your ride feel stiffer.

Rural, northern and work use

If you live up north, in rural areas or use your vehicle for work purposes on rough terrain, you’ll likely experience accelerated wear, especially when towing and hauling heavy items.

So, what can you do? We’ll touch more on this a little bit further below. But aim to conduct routine inspections on your vehicle, especially during the winter months, after driving over potholes and before heading out on a long trip. Early detection of potential issues can help you avoid costly repairs later down the road.

Safety: ABS/ESC/braking and stability

Your suspension system plays a key role in keeping your vehicle safe. Having high-quality, well-maintained components ensures that the tires remain in constant contact with the road, which in turn affects braking performance and the effectiveness of anti-lock braking systems (ABS). Anti-lock braking systems prevent the wheels from locking up when braking heavily, which allows you to slow down while maintaining steering stability.

Similarly, electronic stability control (ESC) works in tandem with the ABS. When the ESC senses differences in steering and vehicle path, it applies the brakes to reduce engine power, helping you stay in your intended direction.

Maintenance and inspection

Like all parts of your vehicle, proper maintenance and routine inspections are the best way to maintain optimal performance levels. Even minor issues, if left unchecked, can lead to reduced comfort, poor vehicle handling and expensive repairs. Here's how you can maintain your vehicle:

Routine checks

To maintain a smooth and safe ride, aim to perform visual inspections of your vehicle for early signs of a bad suspension:

• Shocks and struts: Keep an eye out for fluid leaks, rust or damaged mounts.

• Bushings, ball joints, control arms, sway bars: Look for cracks and other visible damage.

• Tires: Uneven tread patterns and feathering can point to uneven suspension alignment.

• Lubrication: Some of the joints and mounts also require periodic lubrication. Check your vehicle owner’s manual for more information.

Service intervals and longevity

Your car’s suspension system and its components will vary in terms of service life and maintenance interval:

• Shocks and struts: Change every 5 to 10 years or (80,000 to 150,000 kilometres).

• Alignment and tire rotation: Rotate every 8,000 kilometres.

Symptoms and diagnostics

With or without car maintenance routines, you may experience car suspension problems down the road. Common symptoms to pay attention to include:

Handling and comfort symptoms

The most common handling and comfort symptoms to note include:

• Excessive bouncing: Bouncy rides, brake dive, body roll and squat are some of the tell-tale signs your suspension system may not be working the way it should. Remember, your suspension system helps absorb shock, so if your ride becomes harsher, even over small bumps, there’s likely an issue with your shock absorbers.

• Strange noises: Listen closely to see if you can hear any clunking, squeaking or knocking sounds coming from under the car. If you notice this, it could be due to a failed suspension.

• Brake dive: A car that nose dives when braking likely means that there is a suspension issue. A diving feel when braking is the sudden compression of the front suspension.

Tire and steering stability symptoms

Tire and steering wheel symptoms to look out for include:

• Uneven tire wear: Uneven tire wear could indicate that your car’s suspension isn’t putting uneven pressure on the tires, which means that it isn’t functioning as it should be.

• Wandering steering wheel: When steering alignment is off, you may find that your vehicle’s steering wheel is pulling to one side. Your steering wheel may also feel unresponsive or loose, making it difficult to turn correctly.

• Pulling or instability on the highway: When driving at higher speeds, your cabin experience and comfort may deteriorate. You’ll feel every vibration, bump and dip in the road surface.

To test your suspension system, conduct a bounce test. Press down on each corner of your vehicle. If the car suspension works correctly, it should bounce back at you once. If it does more than one, the struts or shocks could be worn.

Alignment guide

Proper alignment helps extend the lifespan of your tires, improves handling stability and keeps your vehicle safe. Take a look:

• When to check: After hitting a pothole, curb or following suspension repairs.

• How it works: Alignment adjusts to caster, toe and camber specifications outlined by the manufacturer.

• Warning signs: Your vehicle pulls to one side, your steering wheel is crooked and your tires wear quickly and unevenly.

Replacement and upgrades

Shocks, springs, bushings and sway bar upgrades can improve handling, but they must be compatible with your vehicle:

OEM vs aftermarket options

OEM vs aftermarket options, which do you choose?

• OEM parts: Match the original design of your vehicle components, are reliable and come with a warranty.

• Aftermarket parts: Can improve vehicle performance and are durable, but quality may vary.

Choosing the right setup

To choose the right setup for your vehicle, consider the following:

• Climate and road conditions in your area.

• Your driving style.

• The type of vehicle you have.

Cost ranges in Canada

The cost of replacement parts can vary based on where in Canada you’re located:

• Shock absorbers that are replaced in pairs (one for each axle) typically cost between $200 and $700 or more, including the cost of the parts themselves and labour.

• Struts will run you around $500 to $1,000 or more per axle. Again, labour costs are included in this.

• Coil springs can cost anywhere from $200 to $600 or more for a pair, with installations included.

• Control arm replacements typically range between $100 and $500 or more.

Keep in mind that luxury and EV vehicles may cost more.

Environmental and recycling notes

Proper disposal and recycling of suspension parts is crucial to minimizing negative environmental impacts:

• Vehicle recycling facilities: The Automotive Recyclers of Canada has 350 end-of-life vehicle recycling and dismantling locations across the country. You can also find a certified auto body shop in your area who follow strict environmental standards when draining fluids and removing other hazardous materials.

• Benefits of proper recycling: Choosing the right avenue to recycle parts and hazardous materials helps support Canadian sustainability efforts and prevents you from receiving fines.

60-second pre-drive check and seasonal checklist

Here’s a quick 60-second car suspension check that can help you spot early signs of wear:

Pre-drive check

Before hitting the road:

• Do a visual inspection of your vehicle, looking for any alignment or leaning issues.

• Check for leaks or oil on the shocks and struts.

• Conduct a bounce test.

Seasonal checklist

Periodically throughout the year, you should:

• Spring: Inspect for winter salt damage, corrosion and check tire pressure.

• Fall: Inspect bushings, control arm and replace worn parts.

• Winter: Install winter tires on your vehicle and top up fluids.

• Long trips: Do a visual inspection of your vehicle and tires.

Remember, early detection can help reduce the chances of costly repairs and ensure your safety while behind the wheel.

Contact BrokerLink today

If you still have questions about how car suspensions work and whether car insurance will cover you to repair or replace a broken car suspension, contact BrokerLink today. We are auto insurance experts and have a team of fully licensed insurance advisors who are ready to help you find a great policy.

We specialize in customized insurance coverage that doesn’t break the bank. So if you’re looking for affordable auto insurance that will cover you against a wide range of risks, look no further than BrokerLink. When you give us a call, you will be matched with an insurance broker who will help you navigate the ins and outs of purchasing an auto insurance policy. They can explain what documents you need for car insurance and even provide you with preventative auto maintenance tips that can help you save money on insurance.

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