Car Shakes When Driving Slow: 18 Reasons Why

Driving at a leisurely speed should be a pleasant experience, right? Well, for some, it is an unsettling journey filled with unexpected (not to mention unwelcome) vibrations. If a car shakes when driving slowly, it could indicate underlying issues demanding attention, bringing us to the focus of today’s guide.

Several factors could be potential culprits behind vibrations, with most triggering other unusual car behaviors.

Here are 18 common reasons a car shakes when driving slow:

1. Uneven Tire Wear
2. Balancing Issues
3. Low Rolling Resistance Tires
4. Wheel Misalignment
5. Impaired Wheel Rim
6. Deteriorated Wheel Bearings
7. Suspension Problems
8. Damaged Steering Components
9. Power Steering Issues
10. Faulty Brake System
11. Bad or Worn CV Joints
12. Damaged Driveshaft
13. Torque Converter Problems
14. Transmission Fluid Issues
15. Damaged or Ill-Fitted Exhaust Components
16. Flawed Engine Anchors
17. Irregular Cylinder Firing
18. Engine Calibration Issues

Worn-out components, tire-and-wheel assembly issues, and out-of-sync mechanisms play a role in slow-speed vibrations. Let us delve further into these culprits. This way, we can prevent our leisurely rides from becoming shaky.

Reasons a Car Shakes When Driving Slow 

Tire-Related Issues:

1. Uneven Tire Wear

Uneven tire tread causes vibrations, especially at lower speeds, due to the unevenness of the tread, creating irregularities in the contact surface between the tire and the road. At slower speeds, each tire rotation takes more time, allowing a driver to feel the variations in tread depth with greater sensitivity.

This slower pace amplifies the effect of uneven wear, making vibrations more apparent and pronounced. In contrast, the vibrations are somewhat masked by dynamic forces and airflow at higher speeds (when tire rotation is faster).

Damaged, worn-out, or bald tires may similarly affect a tire’s contact surface consistency. They should not be confused with uneven tire wear, sidewall bulges, or tread irregularities, as differing circumstances often bring them about.

2. Balancing Issues

In this scenario, uneven weight distribution stemming from out-of-balance tires causes a vehicle to vibrate when driving slowly. While not exclusive to a specific speed range, the symptoms of this issue are particularly noticeable at slower speeds when imbalances are more pronounced.

This imbalance can result from the accumulation of dirt, mud, or other debris or variations in the construction of the tire or wheel. It may also be an aftermath of damage sustained during regular vehicle use, such as hitting a pothole or a curb.

More common but often overlooked causes of out-of-balance tires include incorrect mounting, uneven brake pad wear, and inconsistent (or low) tire pressure across all four tires. The latter can be easily fixed using an Auto Meter 2163 Pro Comp 0-50 PSI Digital Tire Pressure Gauge (view on Amazon) or a similar tool.

3. Low Rolling Resistance Tires

Green or low RR tires are designed to enhance fuel efficiency by reducing the friction between the tire and the road. However, the trade-off for this advantage is often a harder tire compound.

At slower speeds, the reduced flexibility of harder tires can lead to more direct transmission of road imperfections and vibrations to the vehicle’s suspension system. The non-compliant tire sidewalls and tread can result in a less cushioned ride, manifesting as car shakes or vibrations when driving slowly (where the impact of road irregularities is more apparent).

Wheel and Alignment Issues:

4. Wheel Misalignment

The more common outcome of improper wheel alignment is a vehicle pulling to the right (or one side). However, that is not the only issue that wheel misalignment brings about. At slow speeds, misaligned wheels create resistance that can lead to noticeable shaking, impacting the overall smoothness of the ride.

These vibrations typically begin at the steering wheel (view on Amazon) and are eventually felt throughout the vehicle. While it can lead to uneven tire wear when neglected, it is pretty easy to pinpoint its early warning signs — including loose or unresponsive steering, squealing tires, and the inability to drive straight due to a crooked steering wheel.

5. Impaired Wheel Rim

A bent or damaged wheel rim can cause a car to shake when driving slowly due to the disruption in the balanced rotation of the tire. This irregularity — a.k.a. wheel runout — induces an uneven contact surface with the tire, leading to vibrations transmitted through the suspension system.

These vibrations become more noticeable at slower speeds since the affected tires have more time to interact with the misshapen rims. Ultimately, this compromised wheel balance brought about by tangible, external impacts adversely affects the overall smoothness of a ride, necessitating prompt inspection and potential replacement of the compromised wheel rim.

Like unbalanced wheels, damaged rims can result from curbing, scraping, manufacturing defects, potholes, and road hazards. Hence, it is important to exercise caution when driving and steer clear of areas with ongoing road constructions to avoid wheel rim deformation.

6. Deteriorated Wheel Bearings

Wheel bearings are crucial components supporting a vehicle’s weight and enabling the smooth rotation of the wheels. But over time, they can wear out due to mileage, lack of lubrication, or exposure to harsh conditions (among other things). When this occurs, wheel bearings (view on Amazon) introduce play and instability into the wheel assembly.

Like most items in this list, the impact of worn wheel bearings is often more noticeable at slow speeds. The reason is that the rotational forces acting on the wheels are not as intense, allowing worn bearings to produce observable symptoms. Hence, the compromised bearings lead to irregularities that cause a car to noticeably shake when driving slowly.

Although car vibrations are more apparent at slow speeds, they can persist at higher speeds. Furthermore, the severity of the issue may increase with speed and lead to more significant problems if left unaddressed. Replacing worn wheel bearings promptly is paramount in maintaining vehicle safety and performance.

Suspension and Steering Issues:

7. Suspension Problems

Components such as shocks, struts, and springs are integral to the suspension system and are primarily responsible for maintaining stability, handling, and ride comfort. Struts and shocks like Fox Shocks 883-26-073 Rear Shock Absorber (view on Amazon) dampen and control the movement of a car’s suspension. Meanwhile, springs provide support and help manage weight distribution across a vehicle.

When these elements wear out or sustain damage, overall vehicle stability is naturally compromised. Diminished shock and strut efficiency hamper bump absorption, while deteriorated springs affect ride height and weight distribution. These drawbacks often result in noticeable vibrations during slow-speed driving, where the suspension system has a more direct impact on ride comfort.

Worn bushings, responsible for providing cushioning and flexibility to the suspension system, have the same effect on a vehicle as shocks and struts when compromised.

8. Damaged Steering Components

Tie rods and ball joints are pivotal for linking the steering system to the wheels. As these components degrade, the connection between the steering wheel and the knobbies becomes compromised. This leads to increased play and instability in the steering, resulting in reduced responsiveness and car shakes while driving at slow speeds.

The impact of damaged steering components is not exclusive to any specific driving speed. However, the symptoms (including vibrations) are often more evident during slow-speed driving. At lower speeds, the reduced responsiveness of the steering system becomes more noticeable, making vibrations more readily felt by the driver.

That said, promptly addressing damaged steering components is crucial for maintaining optimal handling and reducing car vibrations and the risk of accidents.

9. Power Steering Issues

As extensively discussed in one of my not-so-recent articles, leaks or low fluid levels within the power steering system can significantly affect its efficiency. This is because as fluid levels decrease, the power steering pump (view on Amazon) struggles to provide consistent assistance — leading to ineffective facilitation of what should have otherwise been smooth and effortless steering. This inconsistency, in turn, contributes to vehicle vibrations, especially at lower speeds where precise control is crucial.

Brake-Related Issues:

10. Faulty Brake System

A faulty brake system, encompassing issues like worn-out components, out-of-round brake drums, or fluid leaks, disrupts smooth brake operation, resulting in vibrations during braking. This disruption can also manifest as car shakes, particularly when driving slower.

Brake components like drums, rotors, and pads are always subject to friction and, as such, are expected to wear out over time. While this phase is naturally a part of their life cycle, several factors can cause these brake components to wear out unevenly or prematurely (as follows):

• Aggressive driving habits (frequent hard braking, riding the brakes)
• Low-quality or defective brake component material
• Incorrect or insufficient bedding of new brake pads and rotors
• Lack of lubrication on moving parts
• Corrosion or rust
• Sticking or malfunctioning calipers
• Contaminated brake fluid (often due to moisture absorption)
• Uneven or grooved rotor surface caused by excessive wear or improper machining/resurfacing
• Inadequate cooling of brake drums due to a malfunctioning cooling system or inadequate ventilation
• Heat damage or warping during prolonged or intense braking
• Improper torqueing of wheel nuts or bolts
• Stressful or harsh driving conditions (challenging terrains, stop-and-go traffic)

Drivetrain and Transmission Issues:

11. Bad or Worn CV Joints

Damaged Constant Velocity (CV) joints can lead to car vibrations during slow acceleration. Because these joints facilitate smooth power transfer from the transmission to the wheels, any damage they sustain can result in uneven movement, causing the car to shake uncharacteristically.

While the symptoms of compromised CV joints are more apparent during slow-speed driving, the issue can persist across various driving speeds. It is just that slow acceleration magnifies the impact of irregular power transfer, making vibrations more noticeable.

12. Damaged Driveshaft

Similar to CV joints, a damaged or bent driveshaft can cause dramatic shaking and is not limited to driving slowly. The driveshaft connects the transmission to the wheels. Any distortion in its structure can result in irregular power transmission and noticeable vibrations throughout the vehicle.

13. Torque Converter Problems

When a car shakes when driving slowly and then stops, one aspect worth investigating is the integrity of the torque converter. Specific issues with this component, such as misalignment or damage, have been proven to disrupt power transfer and cause noticeable shaking during slow acceleration.

14. Transmission Fluid Issues

Low or dirty transmission fluid can significantly impact the transmission’s performance and result in shaking. When the transmission fluid is in this state, it affects the system’s efficiency, leading to irregular power delivery and vibrations, especially during slow acceleration.

While the observability of inconsistencies in power delivery is not specific to any driving speed, it is more evident when a vehicle’s demand for power is not as intense.

Exhaust and Engine Issues:

15. Damaged or Ill-Fitted Exhaust Components

Loose or damaged exhaust components, such as a muffler or exhaust pipe, can lead to vibrations. As the exhaust system is an integral part of the vehicle’s overall balance, any component disruption can result in noticeable shaking — at slow speeds or when driving over 70 mph.

This proclivity can occur for both OEM and aftermarket mufflers and exhausts. The same is true for standard and high-performance tailpipes like Corsa 14992BLK Cat Back Exhaust (view on Amazon) — hence, proper installation of exhaust system components is non-negotiable and crucial.

16. Flawed Engine Anchors

Irrespective of the driving speed, engine mounts in a worn or dilapidated state can permit excessive engine movement. Functionally, they should stabilize the engine and absorb vibrations. But when compromised, they fail to effectively dampen engine movements, causing noticeable car shakes — especially during slow driving.

General wear and tear would naturally cause engine mounts to deteriorate over time. However, fluid leakage and physical damage to the mount can prematurely set degradation in motion. Relative to this, I strongly advise regularly inspecting your vehicle’s engine components and hydraulic fluid levels — whether you’re a daily commuter or an off-roading enthusiast.

17. Irregular Cylinder Firing

When a cylinder misfires, it disrupts the precise firing sequence of the engine, leading to uneven power delivery and imbalances. Consequently, the engine’s normal combustion rhythm is disturbed, causing noticeable vibrations.

The impact of a misfiring cylinder is immediate and directly translates into shaking at slow speeds, where the vehicle’s sensitivity to changes in power delivery is higher.

18. Engine Calibration Issues

Several components are critical to an engine’s overall calibration and smooth operation. Issues with the calibration of these components can lead to car shakes when driving slowly.

When experiencing calibration challenges, make sure to inspect the below components. I have included their potential impacts on relevant systems and functions. (The significance of the role of some of these components has also been highlighted in my post on Car Turns Off While Driving but Turns Back On):

• Fuel injectors — uneven fuel delivery to the engine cylinders
• Spark plugs and spark plug wires — disruption of the ignition process, leading to uneven combustion and engine vibrations
• Idle Air Control Valve (IACV) — irregular idling and vibrations when driving slowly
• Throttle Position Sensor (TPS) — detrimental effects on throttle response and engine performance
• Mass Air Flow (MAF) Sensor — inaccurate measurement of incoming air, affecting air-fuel mixture and causing vibrations
• Engine Control Unit (ECU) — subpar vehicle handling and performance
• Camshaft Position (CPS) Sensor — incorrect timing of valve events, leading to engine imbalances and noticeable shaking
• Oxygen or O2 Sensor — adverse impact on air-fuel ratio 
• Variable Valve Timing (VVT) System — desynchronization of valve timing, leading to uneven engine performance
• Intake Manifold Runner Control (IMRC) — adverse impact on airflow in the intake manifold

Conclusion — Car Shakes When Driving Slow

Mechanically savvy car owners should be able to handle regular maintenance tasks like tire rotations or basic inspections. Seasoned drivers can also handle complex issues related to any of these causes, although they often necessitate the skills of a licensed mechanic or technician. If you feel uncertain about addressing any item on this list, I suggest erring on the side of caution and consulting with a professional.