Why Are Motorcycles So Loud? Here’s Your Full Explanation

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Whether you ride a motorcycle or you’re simply curious about their functionality, you may be wondering why motorcycles are louder than other types of vehicles. It is a curious thing because motorcycles are smaller so it sometimes doesn’t make sense that they make more noise.

Why are motorcycles so loud? Motorcycles are so loud because of the size of the muffler most of them have, the length of the exhaust pipes and the lack of residence time the air and exhaust have to slow down, and because the engine is open to air and atmosphere with no engine compartment encasing and stifling the sound.

I’ve been riding motorcycles for a while and have taken many of them apart and put them back together. I’ve been able to see how motorcycles are made and can give you an exact explanation as to why they can be so loud.

Why Motorcycles Are So Loud

Before I started riding motorcycles, I noticed that when I was driving down the road, it was very obvious that a motorcycle was either behind me or I was about to pass one because of how loud it was. Even sitting in the car with the radio on.

I often get the question from riders and non-riders alike about why they’re so loud and if motorcyclists do that on purpose. Though the answer may be simple, it does a deserve a detailed explanation.

When you think of a car and how silent they can be, it’s no wonder people think about why motorcycles are louder. But you do have to remember that cars have a much larger muffler than motorcycles do. It’s actually about 3-4 times bigger than a motorcycle’s muffler. A muffler is what deadens the sound that is coming out of the engine through the exhaust.

Motorcycle mufflers are much smaller, usually no longer than several inches long. That is the biggest reason why motorcycles can be a lot louder than other vehicles. Motorcycles just don’t have the room for a bigger muffler.

The second reason why motorcycles can be so loud is due to the length of the exhaust pipes. The distance from the exhaust port of the engine to the end of the exhaust on most vehicles, like a car, is 10 – 15 feet long whereas on a motorcycle it is only about 3 feet.

The sound and the air rushing out of the engine doesn’t have as much residence time inside the pipe to slow down, bounce off the internal walls, and lose some of it’s energy and velocity. In other words, because the exhaust pipes are shorter on a motorcycle, there is a higher force of exhaust and air coming out of them which makes a louder sound.

The third main reason a motorcycle can be so loud is because the engine is open to air and atmosphere and there is nothing shielding the sound of the pistons going up and down inside the engine. Most people don’t realize that the these processes that go on inside any type of engine can be extremely loud. You have to remember there are thousands of mini explosions per minute going on inside of them.

Other vehicles have an engine that is encased in an engine compartment so a lot of the sound is deadened. A motorcycle obviously doesn’t have that encasing so it’s completely open for any close by ears to easily hear.

Why Are Newer Motorcycles More Quiet Than Older Motorcycles?

You may have noticed that older motorcycles tend to be much louder than newer motorcycles. A lot of people assume that is because older motorcycles were made during a time where it was a fad to have a loud motorcycle whereas nowadays that’s not really so.

There’s actually a lot more to it than that. With older motorcycles, their mufflers have broken down over time and become less effective. Just like any other part or component on a vehicle, the continual usage and air passing through the muffler will eventually break it down. People just tend to not fix the muffler because the break down is gradual and they may not notice it for a while.

Muffler technology, especially in the past few years, has improved tremendously. Newer motorcycles are made with mufflers with the new technology which makes them much more quiet for a longer period of time.

The technology of motorcycle engines has also improved a lot over the years. As time goes on, engines are made with better efficiency which also means they aren’t near as loud as the engines that are on older motorcycles.

A lot of people get “short pipes” where they basically delete the muffler altogether which in turn makes their exhaust pipes shorter. These are incredibly loud and are generally done on older motorcycles which gives the appearance more that older motorcycles are louder.

Why Do Riders Like Loud Motorcycles?

If you’re not the type who likes loud motorcycles, it’s easy to wonder how a rider could like riding a motorcycle that is so loud and not be impacted by it. It can often be annoying for those around them that don’t appreciate it.

There are two main reasons why motorcyclists like having a loud motorcycle. The first reason is that they simply enjoy the loud sound. I can’t give a scientific explanation for that, but some people really do just like hearing how loud their motorcycle can be.

I personally don’t love having extremely loud motorcycles, but I don’t mind the rumble an older motorcycle has. Perhaps the reasons people love their motorcycle being so loud is so they have a way to show off their ride. The noise will certainly get people to look.

But perhaps the biggest reason motorcycle riders like to have loud motorcycles is for safety. A lot of people will argue that having a loud motorcycle can really help with safety, but anything a motorcyclist can do to get other motorists to notice them is worth doing.

When a motorcycle is loud, other drivers around them will be more likely to notice them. As I had mentioned before, I always know when a motorcyclist is nearby because of how loud they were. That in turn makes me much more aware of them and can drive accordingly.

Unaware car drivers are the biggest cause for motorcycle accidents. According to HG.org, “The failure of motorists to detect and recognize motorcycles in traffic is the predominating cause of motorcycle accidents. The driver of the other vehicle involved in collision with the motorcycle did not see the motorcycle before the collision, or did not see the motorcycle until too late to avoid the collision.”

It’s no wonder that motorcyclists want to be loud so they’re more noticeable on the road. There are many unaware drivers out there and since injury is more likely to happen to a motorcycle rider during an accident, having a loud motorcycle can actually seem like a legitimate thing to do.

Motorcycles And Noise Ordinances

While there may be legitimate reasons to have a loud motorcycle, there can be a few drawbacks. Having too loud of a bike can actually get you in trouble with the law.

Most states in the U.S. have laws about noise ordinances and there is actually a federal law that applies to any motorcycle made from 1983 and newer. This is known as the Noise Control Act and it regulates how manufacturers make their motorcycles to ensure they don’t make them too loud.

If someone were to make any alterations to their motorcycle to make them louder, they would need to check in with their local laws to see how loud they can legally make it. Cities will have laws stating what decibel is considered too high on the roads. It’s totally fine to make the alterations you want on your motorcycle, a rider just needs to be aware to not make it too loud.

If you do ride a loud motorcycle that could be pushing the limits of city ordinances, you could be pulled over and given a ticket. You may be an easy target because you aren’t necessarily hard to spot and citizens could easily call you in.

Related Questions

What are the noise limits for motorcycles? Each city and/or state is a little different with their laws and a lot of it depends on the speed of the motorcycle, but in general motorcycles (or any other type of vehicle for the matter) should not be any louder than 80-85 decibels.

Can you tow a motorcycle with your car? It is completely possible to tow a motorcycle with a car. First you’ll need to find out your car’s towing capacity, install the appropriate hitch, find the right trailer, and understand the laws and safety precautions. For more information, see my article here.

This article has been reviewed in accordance with our editorial policy.

Kyle Cannon

Kyle currently works as a mechanical engineer and graduated with a minor in automotive engineering. He loves restoring motorcycles, has a vast knowledge of how they work, and has sold his restoration projects to customers from all over the United States.

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