How Does Baffle Size Affect Motorcycle Sound?

When we hear baffles, we know its job is to quiet down sound. But how exactly do they work? Does size even matter? What else should you know?

In this article, we will talk all about baffles and all the factors that could change the sound of your motorcycle. 

Generally speaking, bigger baffles produce louder motorcycle sound. This is because bigger baffles are much more hollow and they allow sound waves to go through without much disturbance. 

Though, baffle size is not everything! There are so many more important factors that impact your motorcycle sound. Let me explain more – beginning with how do baffles even work?

Motorcycle baffle is a hollow tube that sits inside your exhaust – responsible to quiet down the noise from your engine. 

It’s tubing walls are designed specifically to interrupt sound waves – causing them to bounce into one another and cancel out. This will then result in weaker sound waves and thus, quieter. Pretty simple, eh?

Image of baffle (inserted inside exhaust pipe)

On a motorcycle, baffles are typically inserted right into the exhaust. On bigger vehicles like cars, you may see baffles positioned inside the muffler. 

Baffles become a part of a muffler – which reduces noise even more.

To understand why larger motorcycle baffles are usually louder, we must first understand how sound travels before reaching your ears. 

Sound travels in waves. They become quieter if there are obstacles in their path. These obstacles cause sound waves to bounce on impact and lose their energy.

This is why if you move into a new empty house without furniture, your voice sounds louder. But after fully moving in with your furniture, the house does not sound hollow and your voice is not as loud anymore. 

Same thing applies to motorcycles! Noise from motorcycles is generated from the engine. Motorcycles work using combustion engines – which means they create tiny explosions to generate power. 

These combustions generate energy, large sound waves and exhaust gases – which eventually exit through the exhaust system.

To reduce the noise, manufacturers fit baffles into the exhaust system. Larger baffles are usually louder because they are more hollow with less obstacles – allowing the sound waves to travel freely (less restrictive).

 I keep saying ‘usually louder’ because baffle size is not always the most important factor! Actually, the construction of the baffle / muffler is much more important. 

The more the sound waves collide into obstacles, the lesser noise you will get. A small baffle without any sound suppression design will be much louder than a large baffle with lots of obstacles inside it. 

This is why when it comes to car mufflers, it’s the opposite. Larger car mufflers are usually quieter because they can be fitted with more separations and walls to maximize the sound suppression mechanisms.

Internals of car muffler. The bigger is quieter because more sound suppressor can be fitted in

Okay, enough with the ‘usually’s. Let’s discuss all the factors that actually impact motorcycle sound. 

1. Size of baffle. Bigger baffles are usually more hollow – allowing sound waves to travel without much restriction. And thus, larger sound. We just discussed this extensively above!
2. Packing material. Some baffles are wrapped with packing materials like fiberglass or steel wool. These materials do a good job in absorbing sound waves. Baffles wrapped with some type of packing like fiberglass are much quieter.
3. Size of exhaust pipe. Motorcycles with larger exhaust pipes are usually louder. Same reason as baffle size – larger piping means more hollow – which in turn allows sound waves to travel without much restrictions. Thus, louder! 
4. Engine Size. Motorcycles with larger engines will definitely sound louder. Motorcycle noises come primarily from the engine. So it’s no surprise if larger engines create louder sound! 

I hope those factors make it clear for you on what makes a motorcycle sound louder. I want to touch a little more on the packing materials – because they can change sound significantly.

Baffles packing means wrapping your motorcycle baffles with some type of wool to reduce the noise – it’s really effective and  can work with different materials (with it’s pros and cons) 

Let’s list some of these materials shall we? Note that if you want a loud baffle, this section is not for you. Baffle packings are done to reduce noise! 

But I suggest you keep reading – because why not? It’s good information! Here’s another article where I discuss if quiet baffles impact performance. (if you are into quieter baffles) 

Do Quiet Baffles Impact Performance?

1. Fiberglass 

Fiberglass packing is the most popular and effective one. This means wrapping your baffles in fiberglass and then shoving them back into the exhaust pipe (duh).

Fiberglass is greatest to reduce noise because they absorb sound. However, the noise will start to get louder again as time passes. 

This happens because the fiberglass material may shatter and break as wear and tear.

Baffles with fiberglass packing.

2. Steel / Stainless Steel Wool 

Steel wool packing also works well to reduce noise. However, they are not the best choice because they are prone to rust. 

Exhaust gases that travel through the baffles contain water vapor. After some time, the continuous exposure of steel to water can lead to rusting – which makes your motorcycle shootout brown colored rust. (not great)

Always go for stainless steel wool if you are going with steel. 

Baffle wrapped with stainless steel wool

3. Ceramic Wool

Ceramic wool works great for insulation and sound reduction. This means the heat from exhaust gases will not cause much discoloration to your exhaust tips. 

Any of these materials work great to reduce noise. Just make sure you don’t go stingy when wrapping. Make sure you wrap it enough (in multiple layers) to make sure they are effective and last long. 

Baffle wrapped with ceramic wool

Sure, you could replace your motorcycle baffles with aftermarket ones – it’s literally as easy as removing the existing and slipping the new one in. 

You could even take out your baffle to make your motorcycle sounds way louder. It’s a great option for a loud motorcycle. 

However, I don’t recommend it because it may get too loud! Though, it won’t cause any engine damage – if you are worried. 

I have an article here where I talk more about riding without a baffle. Running A Motorcycle Without Baffles: Is It Bad? 

My take on this entire topic is this – the size of baffles do impact the sound generated. Larger baffles tend to be louder but not always!

The most important factor is the way the baffle is designed. More sound suppressing designs and walls will cause softer sound! 

The other important factor is the packing. If the baffle is wrapped with some types of material like fiberglass or steel wool, it won’t be as loud as a regular baffle without packing. 

I hope this blog has been useful to you and you learn what actually impacts the sound of a motorcycle! See you in my other article.