Why Are Motorbikes Allowed to Be So Loud?

Last updated: February 10, 2023 at 16:22 pm

Motorbikes are significantly louder than a variety of other vehicles you’ll find on the streets. There are a number of reasons for this, and a number of reasons why this is allowed.

In this article:

We will disclose why motorbikes are so noisy and what the law is behind the loudness of motorbikes.

Why Are Motorbikes Louder than Cars?

There is a simple answer to this question. Cars have a much larger muffler than motorbikes, which is why motorbikes are much louder. The purpose of a muffler is to deaden the sound that’s coming from the engine of the vehicle (through the exhaust).

Motorbike mufflers are much smaller as larger mufflers wouldn’t fit on most motorbikes. Another reason that motorbikes tend to be louder than cars is due to the length of the exhaust pipes on the vehicle. Exhaust pipes on a typical car are around 10 feet long whereas an exhaust pipe on a motorbike is typically 3 feet.

The sound and air that goes through these pipes enter and leave quickly due to the size of the pipe, not leaving much time for the sound to lessen, which is what happens with cars. The sound escapes quickly due to lack of space, causing loud noises coming from the motorbike.

Another reason for the loud noise is the lack of engine encasement. A motorbike’s engine is not encased in an engine compartment, unlike many other vehicles. Because of this, anything occurring inside a motorbike (which is a lot, by the way), has nowhere to hide.

Thus:

You’ll be able to hear the engine and other parts of the motorbike more clearly. This is not the case for cars and other vehicles which means that they will omit less noise.

Different Perspectives

One thing to remember is that motorbike riders may not be aware of how loud their bike is, especially to those around them. This is because they may be wearing a quiet helmet. Quiet helmets are great for motorbike riders to enjoy a quiet riding experience so they may not realise how loud their motorbike may be to people who are not wearing these helmets.

Similarly, a motorbike rider may be listening to music on their journey, and this will block out a lot of exterior noise. Having said this, all motorbike riders must comply with the local law no matter what they can hear (or rather, not hear) themselves.

Are Loud Motorbikes Safe?

Some people may not agree with this, but the louder the motorbike is, the safer it arguably is. A motorbike can be a dangerous vehicle to navigate around over vehicles on a busy road, so the louder the better.

A quiet and unnoticeable motorbike is an accident waiting to happen, so many motorbike riders feel safer with louder bikes. If a motorbike is making lots of noise, this will draw attention to it and thus, ensure other vehicles on the road are paying attention to it. If a driver fails to notice a motorbike nearby, they can easily crash into them.

This way, other vehicles sharing the road with motorbikes can give it ample space and avoid any kind of collisions. If motorbikes made the same amount of noise as typical cars do, vehicles sharing the road may not notice that they’re there.

Why are Motorbikes Allowed to Be So Loud?

They are and they aren’t. But this depends on how loud we’re talking. There are laws surrounding the noise levels of a motorbike and this may be slightly different depending on the country you’re in.

1. For example, in America, there is a law called the Noise Control Act, which ensures that manufacturers don’t make their motorbikes too loud and therefore, people can’t purchase extremely loud motorbikes. This includes any motorbikes made since the year 1983.
2. In the UK, motorists must ensure their noise levels are below 82-86 decibels. Motorbikes must pass a test before they are deemed roadworthy. This means customers will then buy motorbikes that pass this test and will be reprimanded if they make any adjustments that go against the local law.

If motorbikes are abiding by these laws and remaining under the noise that’s permitted in their country, they can remain on the roads.

While this may still seem excessively loud for non-motorbike users, it’s quite normal for bikes to give off a louder noise than you would be used to, and this is allowed.

Certain Motorbike Brands

Some motorbike brands don’t have much choice in the matter. Stock Harleys, for example, have restrictive exhaust systems and air cleaners. Along with this, Stock Harleys have a catalytic converter which means less airflow.

Because of this, Stock Harley owners tend to ensure their engine is powerful by removing these obstructions. But this means that the engines are significantly louder than other bikes. In this case, the louder the noise of the motorbike is, the more efficient the motorbike runs.

New Exhausts & Why This Changes the Noise Levels

Some motorbike users may need an exhaust change because their old exhausts have broken down.

In this case, the new exhaust system can sometimes be louder, simply as a result of the way it’s been made. A louder exhaust is safer than a broken-down exhaust.

Related: How to Report a Noisy Car Exhaust [UK]

Has Anything Changed with New Motorbikes?

Newer motorbikes certainly have different features, but this doesn’t mean they are any different in noise levels. Depending on the features, both old and new bikes can reach fast speeds and emit loud engine noises.

Having said this, newer motorbikes on the market tend to come equipped with silencers which are able to significantly reduce the noise they emit. Newer motorbikes contain mufflers that ensure the bikes that are being sold meet the standard noise level that each country states as law. Along with this, many old motorbikes didn’t meet the standard noise level (required by law) when they were sold.

This means that newer motorbikes will certainly emit less noise due to upgraded features that comply with local laws. It all depends on the type of motorbike you purchase, not how old or new it is.

Difficult to Enforce

There are motorbikes that don’t meet the standard noise levels allowed in a certain country that continue to roam the streets freely. This is because it can be difficult to enforce this type of law in certain scenarios.

You may experience a loud motorbike when you’re driving and assume that it does not meet the standard for the country that you’re in, in terms of noise levels. In this case, you can report the motorbike but it’s difficult for the police to measure the sound levels of the motorbike in question. Police lack the equipment to get an accurate reading of the motorbike’s sound levels so it’s difficult to tell if they’re breaking the law or not.

The only thing the police can do is check to see if the muffler on the motorbike has been approved by the official test.

What Can I Do as a Motorbike User?

As someone who uses a motorbike and would like to reduce the noise of your bike slightly, there are some things you can do. A simple solution would be to purchase a silencer for your muffler. Consider the size of the muffler and thus, the size of the silencer that you’ll need to purchase to ensure this works well.

If you’re unsure about any of this, a trained mechanic can give you some advice or extra assistance. There are all kinds of mufflers available on the market, so you can alter the amount of noise your bike emits by choosing a muffler accordingly.

Similarly, if you find that your motorbike is making excessive noise and you’re not sure why, it’s a good idea to inspect the muffler as this can be a good indicator of a muffler that’s broken down. This is quite common in older bikes and there is an easy fix; get a new muffler installed.

Also read: How to Make a Motorcycle Helmet Quieter (Safely)

Conclusion

All in all, motorbikes are allowed to be somewhat loud due to the way they’re built, the features they have, and the need to protect fellow road users.

All motorbike users must comply with the local laws surrounding noise levels.