Why are motorcycles so loud? Explained in detail

Why are motorcycles so loud
Why are motorcycles so loud

Whether you drive a motorcycle or not but while riding on the highway you have heard the noise of a motorcycle. Compared to other vehicles motorcycle being smaller make more sound than any other vehicle. Does that raise the question in everybody’s mind that why these motorcycles are loud? Here is the answer.

Motorcycles are louder because of short-length exhaust pipes and short mufflers with an exposed engine. The short exhaust pipes and muffler fails to reduce the noise coming from the engine. Also, because of the open engine compartment, the sound can travel freely making the motorcycle louder.

I have been riding motorcycles since my teenage and have ridden most of the motorcycle models. Thus, In this article, I will be sharing the reason for a motorcycle being loud with other related useful data that can be helpful for you, 

Why are motorcycles so loud?

Motorcycles are louder because of the short exhaust length and muffler, as it gets very little room to absorb sound while in the car because of the greater length of the exhaust and enclosed environment, most of the noise is get absorbed and output is less noisy than a motorcycle.

In short, here are the reasons motorcycles are loud / noisier.

  • Motorcycle exhaust pipes are smaller in length (around 3 feet to 4 feet)
  • Motorcycle muffler are smaller in size (usually 10 inches or more)
  • The motorcycle engine is open thus it can’t stop the noise

These were the three reasons why motorcycles are loud. Now we will talk and discuss in brief the motorcycle noise.

In vehicles, the sound coming from the engine is passed through the exhaust system. The exhaust system may contain silencers, mufflers, baffles, catalytic converts, etc to minimize the sound. But not every exhaust system contains the necessary components to reduce the noise.

Cars exhaust system
Cars exhaust system

The car has a bigger framework and space, thus cars are equipped with a long exhaust system that can reduce most of the noise while traveling its way out. You can see the picture of the car exhaust system above.  

Motorcycle exhaust system
Motorcycle exhaust system

While the motorcycle exhaust systems are smaller in length thus can’t minimize much sound. Now, see the picture of the motorcycle exhaust above, it’s very small than the car exhaust system.

Motorcycles are made lightweight and have tight space to fit everything in without messing up with overall design and ergonomics. Thus, the motorcycle engine doesn’t get any insulation as it may mess up the design. Apart from this, the exhaust system is also made at most 3 to 4 feet long. Thus, the air rushing out of the motorcycle exhaust doesn’t get enough time to slow down or absorbs the noise thus making a loud noise.

While most of the automobiles exhaust pipes length is 8 to 16 feet long so the air coming out of the engine gets sufficient time to get slow and noise get absorbed helping to reduce the noise coming out significantly.

Apart from this, cars’ engines are encased in an engine compartment that helps to deadened lots of sound.

Why are motorcycles allowed to be so loud?

Motorcycles are not allowed to be loud, from the factory every motorcycle noise remains under the specified limit by EPA. but, as soon as it leaves the factory and arrives to owners. Some owners replace the stock exhaust with the aftermarket or replace the muffler running on straight pipes makes the motorcycle insanely louder.

Thus, the extra loudness of the motorcycles are because of the owners decision, it’s not because of the motorcycle or manufacturers.

For comparison, here I am sharing the sound of stock exhaust motorcycle.

GSXR 1000

Now, I am sharing the audio of Harley-Davidson motorcycle with aftermarket exhaust. Now feel the difference.

Loud Harley-Davidson

The second sound of Harley-Davidson is too much just because of using aftermarket exhaust or mufflers. Thus, motorcycle being loud is also because of their owner.

Harley-Davidson motorcycle sound

The above sound is of Harley-Davidson motorcycle popular “potato-sound”. This was less louder than the above Harley-Davidson.

Is there any noise limit for the motorcycle?

Yes, there is a noise limit for the motorcycle. According to the EPA, any motorcycle manufacturer in or after 1979 cannot exceed a noise level of 84 decibels (dB) when traveling more than 35 mph on a paved street or highway.

But, having a law doesn’t being it will be followed. You may have heard some motorcyclists, sports (racing), and especially Harley sound. These types are louder than other motorcycles on the road. So, what can be the reason that some motorcycles are louder than others even though there is a law for noise limit for motorcycles? Here is the answer.

Why are some motorcycles so loud?

The motorcycles that are louder than others are those that have been modified by their owner. To make these motorcycles louder riders usually replace their stock exhaust with an aftermarket exhaust. While some ride with straight pipes by removing the muffler making their bikes insanely loud.

Thus, because of these rules any way most motorcycles are made with keeping the decibels level in mind. But there are some riders who swap their stock exhaust or muffler and replace them with the aftermarket ones to increase horsepower and sound which increases its noise. Apart from it, there are some people who just remove the muffler from the exhaust and chooses to ride with straight pipes, making the motorcycle much louder than the specified decibels (more than 90 dB). 

In all the motorcycles, Harley motorcycle is louder than other motorcycles. It is famous for its potato sound. In past, Harley Davidson exhaust sound exceeds 100 dB.

Do loud motorcycles really save lives?

Some riders believe that a loud motorcycle makes them noticed on the road thus making a safer ride. These are some myths that generally new riders have.

It is true to some extent in some particular condition otherwise the only thing that can save a life is the way you ride and the level of awareness you have while riding.

The loud exhaust will make you noticed on highways but people will not look at you will any joy. That’ll be the face of irritation and hate. Also, loud noise is not only bad for people around you but also for the environment. Thus, stop giving excuses and stop doing modifications to your motorcycle to make it louder.

For more detail read this post where I have briefly demystified this myth-

Final Word

If you don’t modify the exhaust or muffler then the motorcycle is not that loud from the factory itself. Nowadays most motorcycle exhausts have dB killer or catalytic converter in them that helps to reduce the noise directly or indirectly. The only thing you can do to make the motorcycle quiet is to not use any aftermarket muffler or exhaust that increases the loudness of the motorcycle.

But, if your motorcycle is making more noise and you want to quiet that down read this post where I have shared 8 proven ways to quiet your motorcycle.


How loud is too loud for a motorcycle?

Generally, most motorcycles are made to produces less than 84dB noise from the factory. According to the EPA, any motorcycle manufacturer in or after 1979 cannot exceed a noise level of 84 decibels (dB) when traveling more than 35 mph on a paved street or highway.

Apart from this, excessively loud motorcycles are the result of the owner’s action of modification to their motorcycle. Some rider swaps their exhaust system with aftermarket exhaust which is not EPA-compliant. Thus making the motorcycle louder could easily increase the noise emission to over 100dB.

Does slip-on make motorcycles louder?

Apart from some obvious reason of motorcycles begin naturally louder there are people who are making their motorcycle louder by using an aftermarket exhaust or removing the muffler. 

This raises a question for aftermarket motorcycle exhaust type known as slip-on

Yes, Slip-on makes the motorcycle louder because it replaces the noise-dampening stock muffler of your motorcycle engine giving you the loud rumble that you love.

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