Why are Harley Davidson Motorcycles So Loud?

Why are Harley Davidson Motorcycles So Loud?


Anyone who’s ever witnessed a poker run
knows that Harley-Davidson motorcycles are really, really loud. And since not everyone
thinks that’s a good thing, in recent years, there have been efforts to stifle them. Straight off the line today, Harley exhaust
systems can emit noise as high as 80 decibels (dBs), give or take depending on the model.
For reference, a typical car when idling emits noise at about 35-45 dB and in the high 50s
to low 60s decibel levels at freeway speeds. Even something like a 2008 Ford F-450 truck
only gets as loud as 51 dB when idling and 68 dB when traveling at 65 mph. And while you might think 68 dB isn’t that
far off 80 dB, it’s important to understand that the decibel system is logarithmic- in
this case, an increase in 10 dB means that this sound level is ten times more powerful.
So, for instance, 80 dB would be ten times more sound pressure than 70 dB. For further
reference, when you’re talking with someone in a normal speaking voice, you’re usually
talking at about 60 dB and a lawnmower is usually around 90 dB while a typical military
jet engine averages about 120 dB. Needless to say, apart from older models of
Harleys that could sometimes reach as high as 90-100 dB stock, even today’s 80 dB is
still really loud. This is far in excess of many cities’ noise ordinances, particularly
for residential areas, although it complies with EPA regulations for street level noise.
So why do they make Harleys so loud? For starters, it’s difficult to attain the
level of quietness one sees in a passenger car in a motorcycle due to little room for
bulky mufflers on the bike. That said, loud, powerful sounding engines have become a signature
of this particular brand of motorcycle, leading to the real problem- many who buy Harleys
are not satisfied with the legally regulated stock noise of the engine and instead choose
to swap out the existing exhaust systems for straight pipes that don’t really mute the
engine noise at all. This results in sound that can exceed 100 decibels when revved up. This is extraordinarily loud, and could even
do damage to human hearing. At just 94 decibels (dB) only one hour of exposure can damage
your hearing, while at 100 dB, a mere 15 minutes of exposure will do the trick. Needless to
say, the Harley aficionados who make these modifications and don’t wear proper hearing
protection while riding pay a long-term, ear-ringing price for making their engines sound more
powerful. Given this sort of extreme noise pollution,
there has been a backlash against noisy bikes in recent years, with many local communities
placing restrictions specifically on motorcycle noise, and others banning them altogether. One such effort is EPA stamp enforcement.
Motorcycles are supposed to display EPA stamps on their chassis and exhaust systems that
match each other to ensure the system hasn’t been modified. While previously enforcement
has been lax, more recently communities are mandating compliance, including Denver, CO
(2007), Boston, MA (2009), Arvada, CO (2009), Portland, ME (2009), Green Bay, WI (2009)
and the State of California (2010) So strong is the outcry that the President
and COO of Harley-Davidson, Jim McCaslin, posted a message on the company’s website
in 2009 imploring bikers to not modify their bikes to make them louder. While loud, powerful
sounding engines on Harleys in the past have been something of a selling point, McCaslin
noted the backlash over the noise today is beginning to cause problems. He further implied
that unless bikers piped down, regulations and laws would continue to be put in place
until Harley-Davidson could no longer sell its loud motorcycles and the bikes already
on the road might ultimately be banned completely. McCaslin also directly addressed the custom
of modifying the exhaust to get more power: Testing has proven that straight pipes do
not necessary outperform pipes with lower noise levels. Pick the wrong pipes and you
can severely reduce your horsepower and/or your torque. And while you’re doing it,
you’ll awaken the sleeping giant of social concern that lives next door to all of us. Harley-Davidson has also taken steps to eliminate
the modifications by no longer shipping racing exhaust systems that can work on street models
to dealers. Beyond the argument over increasing power,
enthusiasts in favor of loud exhaust systems often claim that their “loud pipes save
lives,” meaning that because they can be heard, drivers of cars and trucks are alerted
to their presence and won’t hit them. While certainly anyone who’s driven a motorcycle
around much is well aware of the fact that many larger passenger vehicles simply don’t
notice the motorcycles in their blind spots and the like, antagonists note, however, that
the majority of fatal crashes involving motorcycles were caused by the motorcycle rider, at least
according to a 2007 report by the National Highway Traffic Safety Administration. In
the report, it was noted that 45% of fatal motorcycle crashes are single vehicle (meaning
the motorcycle, alone), and that among the remaining 55%, in nearly 75% of the two-vehicle
crashes, the motorcyclist was deemed responsible. That said, the classification of single vehicle
crashes that accounts for 45% of all fatal motorcycle crashes does include “run-off-road
collisions.” The debate rages on.

About the Author: Michael Flood

100 Comments

  1. Now that you now why Harleys are so loud check out this video and find out Why They Say “Mush” to Make Sled Dogs Go:
    https://www.youtube.com/watch?v=OAI5wjopLdY

  2. Why are Harleys so loud???
    For those who are clueless and have their heads buried in phones while driving, "LOUD PIPES SAVE LIVES"!!!
    More cyclists are killed every year by inattentive drivers and the invention of the cheap cell phone made that go up exponentially. The "plugin and tune out" generation is a danger when behind the wheel which is why wearing headphones while driving is illegal.
    I've already had to put a bootprint in some ditzy gal's car door for attempting to make a lane change while I was in it on a quiet Honda.
    I don't have that issue on a Harley.
    All those liberals can suck my Thunder Headers, and they're EPA stamped approved.

  3. They're so loud to piss off the Citizens that don't like loud bikes. It's fun to irritate tight-asses.

  4. Yea the neighborhood Corner Bar with 10 Harley sitting outside I don't think that neighborhoods going to bich about noise

  5. My bikes to loud? Its bothering you? You had to roll your window up? GREAT! You know I'm there and more than likely wont kill me on my ride home from work.

  6. That statistic about multi vehicle fatal crashes is so low because everyone has loud pipes** the answers there in the writing.

  7. The stock pipes on my ‘03 Softail are pretty quiet and not restrictive. Loud pipes are a public nuisance and dangerous to health. Noise testing should be standardized and owners fined.

  8. I call B.S. on the claim that there is no room for a sufficient muffler. I've never heard a scooter sound like a Harley. If loud pipes save lives, all scooter owner would be dead. No need to hear their sh*t for 5 blocks at 3am. This is all about soft, deflated… egos. https://www.youtube.com/watch?v=xAoTXuhW4OU

  9. LOUD PIPED SAVES LIVES SO pleeeze by all means SUCK IT!!!!!!!

    Loud pipes on my two custom Harleys have saved my life COUNTLESS times from you IDIOTIC, APATHETIC, distracted MORONS in your 85db cars with your windows closed and stereos turned up to 125db WHILE TEXTING. So as god as my witness, as long as 4 wheeled uncaring idiotic STOOL SAMPLES with licenses are allowed to kill and injure my friends on the scale it happens, I will NEVER quiet my pipes. In fact one is around 150db and the other full custom about 170db so I wear ear plugs. Again………SUCK IT! My life matters more than your pathetic whining, your loud stereo AND whatever TF you're texting that you feel is more important than a human life. Speaking for bikers; Do the letter FO mean anything to you crybabies?

  10. The Harley V-twin is a fairly large displacement (by motorcycle standards) engine with high compression, a 120 degree crank, and no cooling system to dampen the noise – on the older engines anyway.   Seems like the newer ones have water cooled heads.   If you took a 2 cyl riding lawnmower engine and bumped the compression ratio up to about 9.5 or 10:1 it would be almost as loud

  11. Powerful-sounding, yeah. That kind of sums up Harley-Davidson in a nutshell. The Harley sound, as the manufacturer calls it, seems to be used as a territorial "I'm a sociopath" call. At least outside the US, the image that goes with it is derived entirely from our single exposure to the image – courtesy of the Village People!
    I'll stick to my rice burners (sic), thanks. They put their engineering into performance and efficiency rather than simply the image.

  12. I had a semi not notice me and moved in on my Lane. He didn't hear my horn but when I yanked with clutch and open the throttle he definitely heard that and you'd be surprised how quickly a semi can move. Loud pipes don't just save lives, they saved my life.

  13. Great narrative but that Cueball head , skinny shoulders makes this unbearable to watch so I don’t watch the video I just listen to it like a loud bike by the way loud pipes save lives don’t be a homo don’t like noise wear earplugs .

  14. Who cares why there so loud! If it's to loud your to old! Motorcycles in general shouldn't have the same restrictions as 4 wheeled vehicles in the first place!

  15. My 2016 Street Bob isn’t loud at all, in its stock configuration. It meets noise standards everywhere on earth. I’m good with that.

  16. Reporting stats on causes of motorcycle accidents as being the cause of the motorcyclists in making the case opposed to Harley Davidson bikes is useless useless one breaks down the stats to show sports bikes, Harley, Goldwings, etc. I remember many years ago the talking with the person at the Honda dealership that I was buying insurance for my bike from. I asked him why the insurance prices kept on up on my cheap, used Honda CB360. He said because of the people that haven't rode before, or rode much, buying sports bikes and then in a week or two driving them off the road at high speeds. He said that is what was driving up insurance rates. Swapped out bikes, my cruiser (Honda BTW) for my buddies sports bike, for a ride. He reported that he liked how people noticed my bike more because they heard it and he didn't feel like he was as likely to be hit.

  17. I detest Harley’s because they are so loud. If Harley riders are so concerned with safety, why do so many not wear protective riding gear?

  18. So many Harley owners here say that they have loud bikes to save lives. That may be true for some of you, but the majority not. If keeping yourself safe is so important then why do so many of you ride without helmets? Why don't you wear motorcycle specific clothing with armor? Why all the black clothing and helmets (if you even wear one). Would it kill you to wear something reflective and bright? All the time I see Harley riders at bars. I don't think you're drinking iced tea or soda, then you ride to the next bar. I think conforming to your group, feeling bad-ass and attracting attention are the main motivation. I will also agree that you just like the sound of your bike. Ok, how about a compromise? Go ahead and put on an aftermarket pipe, but limit it to 90 decibels. I can live with that. Any more than that is just a nuisance

  19. Because most HD riders (1) never took neuroscience nor(2)physics and (3) would rather trust their safety to strangers than actually wear a full face lid, jacket, armor, and so on.

    OEM HD pipes are actually not that loud.

  20. Why? So people look around for the noise and magically can see the bike. Eliminates the senile old lady in the cage excuse" i didn't see the bike".

  21. "A motorcycle is a bicycle with a pandemonium attachment and is designed for the especial use of mechanical geniuses, daredevils and lunatics." Atlanta Contitution 1916
    Saw this quote in a Harley dealership.

  22. They are horrible. They shake my house. Terrify and wake up children. On cars this would be unbelievably illegal. This needs to stop!

  23. If you don't "get" why Harleys are loud, you probably don't "get" why V8s are usually loud too.
    Which means we probably don't have much in common…

  24. So this knock off Mr. Rogers is going to complain about loud pipes on Harleys yet nothing about screaming crotch rockets. Yeah he doesnt ride at all.

  25. Don't ride to get there in a hurry…..cagers do. Need 2 hands to control and ride……cagers don't, get off the f$%#*÷g phones! There's an accident with a bike and cage…….cager walking away. Say whatever you want, law or no law, I'm using every advantage I can to enjoy my freedom and rights as a motor vehicle driver to get my ass home in one piece. Next thing you know they'll complain about the LED light upgrades being too bright. Just trying to be noticed with so many idiot and irresponsible cagers on the road today. Just saying

  26. Harley's are loud because of the tools that own them. There are plenty of quiet powerful ones that are owned by people with a brain. Don't just pick noisey Harley there's noisey cars..trucks ..mopeds..Japanese bikes.. all because the owners think it's cool to make a noise. Bloody hell some fools run outboard motors very early in the morning with out being in a drum

  27. The constant vibration and pressure on the testicles causes shrinkage and disfunction. Functionality of the genitals is inversely proportional to how loud people like their motorcycle.

  28. It's a part of Harley/motorcycle culture. It's the same when people with V8's put aftermarket exhausts on their car. Because the sound impresses us and makes our machine feel more alive. You just dont GET it. Not everyone is a petrol/gear head and can understand why our bikes are loud and it's making me exhausted that people that dont ride are trying to regulate how much fun we can have. And not everyone that has a loud machine is suffering from an inferiority complex or has a tiny dick. Some folks out there are like that and their egos get ahold of them but to generalize and say all Harley guys are douchebags is quite ignorant. Some of the nicest and most down to earth people ride Harleys. They smoke, drink, and have tattoos all over but are the most real individuals I've ever met. I see more assholes wearing business suits and driving priuses. The biker community is tight knit and we might sometimes seem like fuckfaces but it's usually toward people that judge us without knowing us and of course, surprise surprise. They dont ride. Also anything with a good aftermarket exhaust system can be loud. My buddy had a Triumph Daytona 675 with an aftermarket exhaust and he scared the shit out of me one day when we were riding through an echoey overpass. I didn't get mad though, I laughed because I love the way motorcycles and engines sound when opened up. So if you don't ride and you hate noisy engines well that's tough luck for you because it's never going away. And to all bikers that prefer quiet motorcycles I have nothing but pure respect for ya, I just like the rumble a V-twin makes with a nice set of pipes. So lets quit judging people's characters based off of what they ride/drive….unless it's a prius, and let's just agree that we are all brothers and sisters on two wheels. Ride safe and keep the rubber side down. Cheers from Utah. #Harleydavidson #Livetorideridetolive

  29. Loud pipes save lives and I've seen it in action… Harleys are gay? Then ask yourself why they have been in business for 116 years and going…. And as for little dick oviously you never went to Daytona or Sturgis…. Lol… I guarantee we get all the pussy we need… Lol… If you don't like bikes just move on , I really don't give a shit… It's a way of life… You have yours I have mine….

  30. Odd how people only think of Harley's specifically when people mention noise. Some race bikes can be MUCH louder but with just higher pitch.
    Not only that, but many people who see a cruiser type bike think its a Harley but could be anything from american to european and even japanese.

  31. Assholes the reason is assholes dumb assholes.if they where quick ok but then a quick bike should only be on a track. Unless your an asshole.

  32. I watched this video hoping to find out why they are loud not that people straight pipe them to make them louder…

  33. Of course this video is made by someone who doesnt ride … my pipes have saved my life many times from jack asses in cars more then once and trust me the horn is not as effective as my pipes , rather be deff then dead , and another thing its not the noise that will stop bikes from being on the road its polititions and insurance companies….

  34. Of course the most liberal tree hugging left wing nut city's and state would ban loud exhaust. Most Harley riders want to make America great again!

  35. The interior of a standard modern semi truck can reach 80 dB at 65 mph. You can't hear a car horn unless they're right next to you. Unless they're blowing past you at 150 mph, you can hear loud pipes from some distance.
    Even if the manufacturer won't sell loud pipe, it's not like the biker can't go to their local auto parts store and buy exhaust pipe or cut out the baffling.

  36. I have a LOUD M109R bike which is awesome!😎 … and my loud pipes (in cruzin mode) did alert and stopped two tunnel vision kids running in between parked cars out in front of me.
    They couldn't see me but they sure did hear me. So loud pipes do save lives and it's worth it. 👍
    Also, it wakes up dumb people that don't wanna look at me.
    I did have quiet pipes once on my M109R but when a driver cut me off badly, I asked didn't you see me and he replied that he couldn't hear me coming…. Go figure!🤔
    Also, when I had my Quaker 250 with the quiet stock pipes I would beep my horn to alert those "people" that I'm driving here but then found out that beeping your horn here in Adelaide just makes people angrier!😆 Sooo… loud pipes it is!

  37. The reason they are so loud is because the owners replace the factory pipes( that contain a muffler) with straight pipes with no muffler or pipes designed to actually be louder.

  38. Please don't forget all the other riders of import race style bikes that make most Harleys sound quiet. And also don't forget that there are a lot of us who don't have loud pipes on our bikes. Its not right to stereotype all Harley owners when in reality there are just as many import bikes, Supercar and Musclecar owners that are just as guilty if not more so. Seriously people need to think before they hate on people…

  39. Vehicles have blind spots and idiots who don't pay attention. Bikes need to be heard since you can't see past your phone screen

  40. Considering how blind US automobile drivers have proven themselves to be even in the face of multiple motorcycle headlights, I consider them retarded. Harleys at least announce their approach, and if US auto drivers cannot even sense that, guess who should be taken off the road?

  41. I think that human social life is cruel. Men with small penises are forced to stigmatize themselves in public with a roaring exhaust sound.
    Amnestize all small dicked men! Allow them normal exhaust systems! Give them back their dignity!

  42. It doesn't bug me too much when I see a reckless bike rider because it's not like people other than the rider are injured or killed by that motorcycle.

  43. I have a RC Pulse Jet that makes 140 decibels.Many New Harley davidson bikes make more noise than my jet on full throttle. I am going to film & record Decibel levels from them on my property to show you all.

  44. Stupid. I've been next to many big bikes. Some I can barely hear over my stock truck exhaust. They are just annoying slow pretenders. Mostly.

  45. Why thank you so much Mr obvious 80 db is 10 times louder than 70 db whew im so glad i viewed this gosh thanks Mr obvious thats where the vroom came from when i see a harley go by………………

  46. Motorcycling is a different consciousness brother, it's not for the weak of heart or the hearing it seems. Only the finest become riders and we really don't need be concerned about the puny. We love how our babies sound.

  47. They are obnoxiously loud to prompt the owner's neighbors to take a dump in their mailbox in the middle of the night.. hypothetically.

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