A dangerous myth: Loud pipes alert car drivers

[JWALKER]

i agree you shouldn't put everything on the fact you gave a loud pipes and a car will hear and see ya. but, at the same time i think they are a good warning to people who are oblivous to everythin going on aronud them, my bike has aftermarket pipes on it and i have had a few different people say they can hear me come up the other end the street before i arrive and i know that cage drivers can hear them, wether im frony, back or beside them

[Lou Girardin]

With even family cars being so well sealed that they have db ratings of 75 - 80, how do you really think a 98 db exhaust is going to be heard from a distance?

[yungatart]

Exactly! Especially when they have the stereo going or kids fighting in the back seat, the chances of hearing anything outside the car are negligible...

[sAsLEX]

With even family cars being so well sealed that they have db ratings of 75 - 80, how do you really think a 98 db exhaust is going to be heard from a distance?

What do you meanby 75db? is that the normal noise heard cruising round, or is this the attenuation from outside sources.

and some random comparison levels

Sounds dB SPL
Rocket Launching 180
Jet Engine 140
Thunderclap, Air Raid Siren 1 Meter 130
Jet takeoff (200 ft) 120
Rock Concert, Discotheque 110
Firecrackers, Subway Train 100
Heavy Truck (15 Meter), City Traffic 90
Alarm Clock (1 Meter), Hair Dryer 80
Noisy Restaurant, Business Office 70
Air Conditioning Unit, Conversational Speech 60
Light Traffic (50 Meter), Average Home 50
Living Room, Quiet Office 40
Library, Soft Whisper (5 Meter) 30
Broadcasting Studio, Rustling Leaves 20
Hearing Threshold 0

[dawnrazor]

Loud pipes DON'T save lives, alls they do if annoy the neighbours, attract unwanted attention from PC plod and potentially make you deaf, depending on the quality of your helmet and if you where earplugs. Why advertise your presence to the people who are in no danger of getting in your way, but have the potential to stop your fun.

I went for a ride with a mate who was on a 996 monster with lafranconi pipes, I litterally could not ride behind him, the shock wave was "shocking", even four feet back, I couldn't hear my own engine or road noise, had to get ahead of him - the difference was amazing, lord knows what its like to ride.

Give me induction howl any day of the week, puts a grin on my face every time it winds up, fantastic.

[vifferman]

dont count on that i think it was vifferman firestormer or whatever his handle is now, you all know the on with the descriptive language, that had a pedestrian move in front of his loud bike

Wha...?!? [snort] [yawn]
You woke me up.

Nah, it wasn't partickerly loud - just a VFR750 with a mysterious hole through the main zorst baffle, and the usual cakemixer sounds from the engine. But (however) I did tootle melodiously with the horn, to alert the errant pedestrians that I was on my way towards them. Unfortunately, one chose to ignore my tune, until she took fright at being stranded in the middle of the road, with traffic whizzing by, and thought it was safer to leap in front of my motorvelocipede. Even more unfortunately, the aforementioned motorvelocipede took umbrage at this unannounced invasion of its personal space, and attacked her leg.
Then her leg bone took issue with this rude introduction of tyre to limb and broke here and there.

Back to the loud pipes - you often can hear them before they get to you, but sometimes the sudden loud noise for those who either don't hear them or can't work out where the noise is coming from (as is the case with low frequency sound waves) get such a fright that the result is not conducive to road safety or indeed saving lives.

My current pipe is loud(ish) because I can. Or because my can can. (Not the Gallic dance, sorry). However, I choose (mostly) not to run it in in "Look at me! LOOK AT ME!!!" mode, as it's too friggin' loud, attracts to much attention, and gets on my nerves.

[chickenfunkstar]

I'm not suggesting that loud pipes give you a licence to ride aggressivly though traffic, but I still fail to see the argument that they make no difference to your saftey at all. If you're passing cars on the motorway (i.e. you have to ride through a cars blind spot), isn't it better to make cars as aware of your presence as you possibly can?

[dawnrazor]

Does everyone not remember the dopple effect from school?

A bike traveling at speed towards a stationary object will push a sound wave infront of it and compress that wave as it moves forward, sooooo depending on the frequency and pitch of the pipe and the speed traveled at the precieved sound will certainly be of higher frequency, with harmonics that are inaudible to humans, (might be good for dogs though!), also consider that a pipe faces in the opposite direction to common forward momentum and you get to a situation where the pipe has to be VERY loud for its effect on the stationary object in its path to be considerable, but the moment it passes that object it deafens everyone in its wake, as now the sound wave is stretched and predictably completely audible. Hmmmm, thats useful, lets everyone know where you've been and frightens small animals.

[Grahameeboy]

I think we need to 'Can' this post and 'Muffle' it right now chaps.......

[dawnrazor]

I think we need to 'Can' this post and 'Muffle' it right now chaps.......

I'm baffled

[Grahameeboy]

I'm baffled

Oh very good Ms Razor.........now will you 'pipe' down.....he he lol

[Jackrat]

Sounds to me that people who drive poofters cars are just deaf.
I hear bikes coming up behind me on a regular basis,and not all of them are Harleys running straight pipes either.

[ZeroIndex]

all bikes really need to keep cars clear is a nice set of circular saws or laser beams... LOL.. ok, don't read this post

[Grahameeboy]

all bikes really need to keep cars clear is a nice set of circular saws or laser beams... LOL.. ok, don't read this post

Pardon I didn't hear that.....

[Motu]

Loud pipes aren't to effective at motorway speeds,but they are pretty good at waking up dozy drivers at intersections,if you have something that barks on the over run they certainly look up if you chop it down and back off.My old BSA running Goldy cams and an open megaphone sounded like it was tearing the very fabric of time and space,at 5.30am going to work it sounded like 425db at the very least.