4 Reasons Why Humming Noise in Car Getting Louder with Speed

"Why does my humming sound get louder as I accelerate?" you ask. And you know it's not wind, road surface, rooftop cargo carrier, or open windows that make this rumbling sound as you speed up.

Let's check which malfunctions in your car generate the roar so you can assess the problem's severity and the potential costs.

So the humming noise in a car getting louder with speed appears due to:

• Bad wheel bearings
• Deep-groove tread designs
• Unevenly worn tires
• Transmission failure.

And below, we'll explain how exactly the rumble appears.

4 Causes for humming sounds in cars when driving

Ignoring unwanted sounds in your car, like clicking, grinding, whining, etc., can be costly and dangerous. Let's learn what problems the humming noise flags.

1. Bad wheel bearings

A wheel bearing is located in a hub in the center of each wheel. Each bearing consists of a metal ring (race) containing steel balls isolated from water and dust.

This mechanism operates at the connection of the rotating wheels of a car and its static body. The moving power goes from the transmission to the wheel hub, and wheel bearings meet this rotation.

So these elements suffer a lot of loads while you drive as they take over radial forces and support the car's weight. Additionally, bearings absorb the impact of potholes and bumps on roads.

As a result, races get damaged and penetrated. This deforms the balls and allows the grease to leak. The growing friction heats the details and warps them too.

Water gets inside bearings and causes corrosion, while the dust and small pieces of metal get in between the balls.

All these factors provoke the humming noise when you start driving, and the sound worsens as you speed up.

What to do

You'll need to visit a car service to get faulty wheel bearings replaced. Professionals recommend replacing two bearings on the same axle as the other one will probably fail shortly.

Driving with worn-out wheel bearings is dangerous as your wheel can get blocked or even fall away. In less severe cases, damaged bearing affects all the linked mechanisms: the hub, the CV joint, and the transmission.

2. Deep-groove tread designs

A car making humming noise at 40 mph and more probably has issues with the tires.

The tread pattern on a tire allows drivers to keep traction on rainy and snowy roads. Water goes away through grooves and sides, helping the vehicle avoid hydroplaning.

But it's not only water that travels under your wheels, as air also does this. And the humming sound will intensify together with the depth of the grooves or "height" of tread blocks.

That's why some tires can be more noisy than others. For instance, off-road and heavy-duty tires have deeper tread patterns and, thus, produce a loud humming noise. At the same time, the bolides boast slick tires and quiet rides.

The rubber compound also impacts the sound. Summer tires are more robust, which causes more vibration and, consequently, humming when they contact the road surface.

A wider tire sounds louder than a thin one as its contact patch is larger. The same is true for overinflated tires.

What to do

Make sure you use tires of the right size and for relevant seasons and terrain. Check if the air pressure equals the level recommended by the manufacturer.

If you still hear the annoying rumble, consider changing the tire brand. Or that's probably the only case when we recommend ignoring the sound and turning the music louder. Still, before that, read the following section.

Unevenly worn tires

The next answer to your "Why does my car hum louder the faster I go?" is "Due to uneven tire wear." As the air moves through grooves of unequal depth, loud humming intensifies.

The unequally-worn-tires problem often goes together with vibrations, also contributing to the humming noise. But what's the cause?

Uneven wear of tires happens due to several reasons. The first is misaligned wheels. Such wheels can have six improper positions. They can be tilted inwards or outwards when viewed from above and from the front of a car.

The remaining two faulty tire positions will have either a positive or negative caster angle — the difference between the vertical and the steering axis of the vehicle.

The second reason for irregular tire wear is unbalanced wheels. Each wheel-tire pair has to be balanced along the circumference. This way, the weight is evenly distributed with respect to the wheel's center.

The third cause for feathering or cupping tires is worn suspension parts. They connect wheels and chassis, helping you manage the vehicle and keeping passengers safe from bumps.

So once any suspension part fails, your wheels suffer more unbalanced load, and tires wear off unevenly.

What to do

You'll need to take your car for wheel alignment and wheel balance. Also, you'd better check the ball joints, control arm, coil springs, anti-roll bar, and other suspension system components.

Only after that does it make sense to replace worn tires. Once done, you'll be enjoying hum-free rides again.

Transmission failure

The transmission transfers power from the engine to the wheels, ensuring the heart of your car moves at the right pace.

If the humming comes from your transmission, the bearings, and other transmission elements don't run smoothly. This is possibly due to a lack of oil.

So once you have leakage or a low transmission fluid level, the gearbox will produce annoying bussing.

Note that once you have issues with the transmission fluid pump, you'd rather hear whining than humming noises. However, your transmission is packed with many details that can also generate clicking or knocking sounds. And should never ignore them.

What to do

First, top up the transmission fluid reservoir to the required level. Then take your car to transmission diagnostics even if the humming sound disappears.

Mechanics will either confirm that yiur car is healthy or run a minor transmission repair. This will help you avoid more severe problems with the transmission.

Summing up

Bad wheel bearings, worn tires, specific tread patterns, and transmission failures won't let you enjoy the humming-less drive. But once you identify and fix the problem, the loud noise from the front end of your car might disappear.

That's when your trips will become comfortable and safe again.