Why are motorcycles so loud? You may ask! That could have to do with the size of the mufflers on them, the overall length of pipes, the lack of sufficient air and exhaust residence times, and the fact that motorcycle engines are exposed with no casing to muffle the sound.
People also frequently modify their bikes to be intentionally loud, and that makes the subject of this post. Is it legal or even safer as most proponents swear? Let’s find out.
Why “Loud Pipes Save Lives” Is a Misconception?
Are Loud Exhausts Legal?
High muffler loudness is not a correctable offense under most states’ “Loud Exhaust Law,” as of this writing. Operators of overly loud motorcycles can and will be punished, with no chance to have the amount waived if the problem is corrected.
We all crave that lovely hum of an inline-four motorcycle racing down a highway. However, there is a limit. You must adhere to particular motorcycle noise limitations to preserve your hearing, be respectful to others, and keep your pipe noise within legal boundaries.
Why Are Motorcycles Louder Than Cars?
Motorcycles are generally louder than cars because their engine’s power band is situated at considerably higher RPM and will have to run faster and louder under normal operation. They also have a shorter pipe length, which implies less residency time in the pipe for the air and exhaust to decelerate on its way out. Additionally, unlike motorcycle engines which are exposed, car engines are enclosed in a large sheet metal cage that absorbs much of the noise generated.
Different engines create their distinct sound profiles by releasing pressurized gas from the cylinders, then passing it through the exhaust valves and exhaust system. Some designs have such distinct sounds that they are immediately recognizable even before the bike is seen.
Is it Better to Have a Loud Motorcycle? Are Louder Motorcycles Safer?
Motorcycles with loud pipes are not safer. Riders should instead turn on their headlights or wear brightly colored safety gear to ensure that other motorists can see them.
The belief that “loud pipes save lives” is one that persists. The claim is that the louder your motorcycle’s exhaust, the safer you will be. However, several new studies have completely refuted this claim.
First, Romanian research has debunked this popular myth completely with the results clearly indicating that loud pipes are not very audible in car cabins and that riders are then exposed to false confidence and end up crashing. The researchers found that some of the world’s loudest bikes can’t be heard in a typical car that is 50 feet away.
That’s true even when the loudest motorcycle’s exhaust reaches 110 decibels. According to the University of Michigan, that’s chainsaw-level loud. Plus, even when the distance was reduced to 33 feet, just one bike could be heard clearly inside the vehicle.
The Hurt Report of 1981, North America’s most well-known research on motorcycle safety, also found that motorcycles with loud exhaust were not less likely to be involved in accidents. In fact, they had a slightly increased chance of getting in a crash.
The Doppler Effect Suggests Otherwise
Doppler effect is the apparent difference in the frequency at which sound leaves a source and the frequency of sound arriving at an observer, produced by the relative velocity of the observer and the wave source. Simply, we hear noisy motorcyclists approaching, but we don’t perceive much of the noise until they’re very next to us or have passed.
Many riders defend loud pipes by claiming that they are safer since drivers in front of them can hear them and will drive more cautiously as a result. The Doppler effect, on the other hand, suggests differently.
How Loud Is Too Loud for a Motorcycle?
The current maximum permissible noise level for a motorcycle is 82-86 dB, with the bracket varying based on engine capacity. To account for the impacts of any wear and tear, most police departments set a maximum of 90 decibels. This is a reasonable limit because noise levels above 85 dBA can cause noise fatigue and hearing loss.
Can Motorcycles Be Made Quieter?
You can make your loud motorcycle quieter by restoring or replacing your current exhaust system with the stock option or a quieter aftermarket version.
Almost every standard bike is designed to be extremely quiet. The problem is that riders want to replace them with aftermarket “mufflers,” which are essentially noise amplifiers. Technically, this is against the law, yet it is rarely enforced.
While some riders may continue to defend loud pipes as a safety precaution, the facts from research tend to contradict their arguments. Motorcycles with loud pipes are not safer, and loud pipes do not save lives. They can, on the other hand, provide riders a false sense of security about their safety, leading to unsafe riding situations.
Loud pipes have been a source of irritation for both the general public and businesses, where they negatively impact the quality of life.
About the author: Michael Parrotte was the Vice President of AGV Helmets America, and a consultant for KBC Helmets, Vemar Helmets, Suomy Helmets, Marushin Helmets, KYT Helmets, Sparx Helmets. In addition, he is the founder and owner of AGV Sports Group.