Why Do 18 Wheelers Use Drum Brakes?

Drum brakes are distinctive in their style in comparison to disc brakes. They’re an older style, 1st showing in 1902. These days they’re typically solely found in heavy vehicles like semi-trucks. But have you ever thought about Why Do 18 Wheelers Use Drum Brakes?

Smaller vehicles like cars and SUVs have touched on to form the use of disc brakes. Brake discs usually have additional stopping power than drum brakes. It’s estimated that disc brakes are between twenty and forty percent simpler in stopping a vehicle.

Drum brakes are cylindrical, therefore the name. However, the difference is that the brake shoes are on within the drum, and they push outward to supply friction. The friction is employed to slow the vehicle down. this can be distinctive to semi-trucks in modern times, and there are many reasons why they need not touched brake discs.

18 Wheelers Use Drum Brakes

Reasons Why Do 18 Wheelers Use Drum Brakes??

You might be wondering Why 18-wheelers use drum brakes?  That’s over one hundred years previous to preventing themselves. There are some superb reasons for semi-trucks to use drum brakes as opposed to disc brakes although. Despite disc brakes having higher stopping power, there are some blessings that drum brakes have over them.

The first is that they’re cheaper and easier to manufacture. Drum brakes bear tons of strain; thus, exploitation of the more affordable possibility is best for business. Another advantage that drum brakes have over disc brakes is that they’re lighter. amazingly, the older style is truly not heavier.

In a vehicle that’s already extraordinarily serious, saving as much weight as possible is important. Drum brakes can facilitate bringing the weight of the semi-truck down. Drum brakes also are stronger. Since trucks are serious and they put plenty of strain on their brakes, having heavy brakes is important.

Are Drum Brakes Air Brakes In A Semi Truck?

The drum brakes on a semi-truck build use of compressed air to push the shoes into the drum and cause friction to slow the vehicle down. The air brakes on a semi-truck need an engine-mounted compressor. The compressor shoots out high pressured air into the brake line that activates the brakes.  Air brakes are helpful in semi-trucks because they’re abundant and stronger than hydraulic brakes.  It conjointly makes it easier to attach the brakes on multiple trailers behind the tractor.

The air brake is additionally far more reliable than hydraulic brakes, and that they will still perform although there’s a leak in one among the brake lines. An air brake is additionally considerably cheaper and easier to keep up. Coupled with the drum brakes, you have got the foremost inexpensive combination to keep up for your semi truck’s braking system.

How Many Brake Drums Do Semi Trucks Have?

Semi-trucks are ordinarily heavily loaded. this implies they have plenty of stopping power to slow themselves down expeditiously. Semi-trucks have brakes on every axle. the typical 18-wheeler has five axles, which implies it’s ten brakes in total.

However, it depends on how many trailers it’s towing. For instance, the tractor itself solely has 2 axles, and thus its four drum brakes. Extra brakes are placed on the trailers, that are connected to the brake on the tractor using airlines. All the brakes can then be operated in sets with compressed air.

How Do Drum Brakes Work?

Drum brakes work otherwise than the disc brakes that we find on our everyday road cars. they’re pretty distinctive in their style too. Drum brakes are composed of an enclosed cylinder. The name drum brakes return from this style since it resembles a drum.

The brake shoes are found within the drum. On the opposite hand, on brake discs, the shoes are often found within the clamps that hold onto the brake disc. When the brake pedal is pressed, compressed air is discharged into the brake lines.

The air pushes the brake shoes outward against the drum. The friction caused by the shoes being pushed against the drum is what slows the vehicle down. With brake discs, hydraulic pressure is employed to clamp the brake shoes onto the disc, which causes friction that slows it down.

Advantages Of Drum Brakes

Despite being supported by a far older style, there are many advantages to the exploitation of drum brakes on a semi-truck. It’s rare to search out drum brakes on fashionable cars, however, on semi-trucks they’re still an awfully common sight.


So, drum brakes have a lot of advantages. That’s all we have Why Do 18 Wheelers Use Drum Brakes??  When drum brakes work too exhausting, they produce a massive quantity of heat. The warmth will cause the drum to expand, which can build the brakes less effective. Regularly pairing and substitution the drum brakes and therefore the brake shoes also will help to extend their lifetime.

Frequently Asked Questions

Why disc brakes are not employed in trucks?

Another reason we do not typically use a disk is we do not want it. we’ve got enough braking power using drums to lock up eighteen wheels if we strive exhausting enough. The limiting issue to us stopping is skidding and also the rubber not riveting the road. additional powerful brakes won’t facilitate who stop sooner since they don’t facilitate tires grip higher.

Are drum brakes heavier than discs?

Drum brakes have some major style flaws: they overheat too quickly, take longer to dry off, and are generally heavier than disc brakes. At the same time, disc brakes can’t be used as a brakes as a result of they expand once hot and contract once cold.

Do drum brakes have rotors?

There are 2 styles of brakes: disc and drum. Disc brakes comprise a disc, additionally called a rotor, that spins in conjunction with your wheels. to prevent your wheels, brake pads, that are placed within the caliper, press against the rotor to forestall it from turning. With Drum brakes, the drum spins along with the wheels.

Our rear disc brakes price it?

Some trendy vehicles still go with drum brakes on rear wheels. Rear drum brakes are cheaper to supply than disc brakes, and since a vehicle’s front brakes truly do seventy p.c of the work, rear brake performance may be sacrificed for price.

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