Motorcycle Riding — What Decibel (dB) Levels Can One Be Exposed to via Bone Conduction?

Hi!

I know it's been often discussed, but I'm looking for scientific data on what levels of noise can reach the inner ear via bone conduction.

I really don't want to give up motorcycle riding, my plan is to use my custom-made earplugs (that go into the canal and covers the inner hollow part, concha, of the outer ear. They are certified for 32 dB on all frequencies, but as I understand the low-frequency sounds can still cause trouble through bone conduction.

Of course, on top of it all, the helmet also takes some of the noise by some degree, but I think it is impossible to measure correctly, as it is a multifactorial question. I have a Schubert C4 Pro helmet, which supposed to achieve approx. 85 dB(A) at 100 km/h on a naked motorcycle.

I only ride in the city, so wind noise is not a concern of mine, the usual traveling speed is no more than 70km/h.

Is there any dampening in effect by the body or a low freq sound ex.: 100 dB noise can reach the inner ear in its full strength?

As a side note, the motorbike is as quiet as possible, it is not a crazy speed bike with sport exhausts (it's a Triumph Bonneville T100 to be exact), the exhausts have silencers and it conforms with the US E.P.A. emission regulation, which is for 80 dB(A) but it is tested from about 5-6 meters (from the pedestrian point of exposure. For the rider, the noise exposure is around 95-105 dB max that I measured.

I had mild tinnitus for 13 years, over the last couple of months it turned up a notch a bit (not directly because of motorcycle riding), so I can say it is mildly severe, but if safe riding is impossible to achieve, I won't risk it to make it any worse.

Since I had to eliminate every possible source of noise exposure from my life (parties, concerts, clubs, even loud restaurants, etc.) this activity would be a tough one to let go but I accept if safety can't be guaranteed.

Thanks.

 

@Robin21

I'm not aware of any paper that details what you're asking. However, dampening does occur naturally as simple physics of wave propagation in a medium. The question is how much.

Perhaps you can consider an e-bike. There is a decent amount of choice nowadays.
https://www.zeromotorcycles.com is one example (there are others).

Good luck!

 

It seems very straight-forward, but I got further hearing loss and worse tinnitus after using a 100 dB hedge trimmer with over ear and in-ear protection for 20 minutes. The theoreticals just can't be relied on for something so life-altering.

I would give the motorcycle riding up. Once tinnitus starts, loud things say bye bye or you learn the hard way. Also what can you do when youre in a bike and a 130db Ferrari or Harley pulls up next to you?

 

It's really hard to say, but on a bike bone conduction is not your biggest noise concern, and also I sort of think anyone looking at motorcycles from a "bad for ears??" perspective is not being super realistic about things, because these are machines that will absolutely wreck your entire body at the drop of a hat. An old acquintence had a handyman who has spent most of the last 20 years living with no face because he went face first into a road barrier when his kickstand threw the bike. (Also, wear full face helmets and put your kickstand up!)

Bikes have a huge range of noise levels but assuming you get something reasonable, then wind noise, is, ultimately, a bigger problem. Noise absorbed through bone conduction is substantially attenuated by the body (~30 dB?) -- however, at highway speeds, noise across your helmet can easily exceed 100 dB. It doesn't impact the kind of riding I do very much because I do dirt roads at 35-50 mph mostly, and not around other cars.

I've never heard a chopped Harley that was anywhere near that loud, but, since I wear a helmet with thick plugs under it, if this happened I would simply take a picture of the driver's license so that I could let the state know they should go talk to this person about their insanely illegal transmission

In general motorcycles around here are not as loud as my mower / chainsaws / etc.

Er, sorry, but do you have audiograms? What are you basing "further hearing loss from this one incident on"?

NRR is misleading but even so 100 dB is well within the range where you're fully protected if plugs are 100% correctly inserted, etc; additionally, hearing degradation over a period of time, even if it's clinically confirmed, gets harder and harder to tie to as a specific event as we get into our mid 20s and beyond and the cumulative damage from years past starts to add up.

All of that said, motorcycles are loud as hell, and even though I got into this stupid hobby after I blasted my ears pretty good already (tinnitus since 1999, motorcycles since 2013), I wouldn't encourage anyone else to, per se. I've been riding for, uh, 8-9 years now and I don't attribute any changes in my tinnitus to that but of course I'll have to get back to you in another 10 years since these things can take time to add up, eh?

For what it's worth you have a really nice bike and if I still lived someplace where I was riding 90%+ on pavement, that would be pretty high on my wish lists. I am riding a little Enfield Himalayan now.

 

Your bike is cool as hell too It looks like fun to ride on those dirt roads. I've tried dirt track racing once and it was awesome! Of course, smooth pavement is also very nice when you just want to travel in peace

Yes, the Bonneville was my dream bike too. Got it 2 years ago...

I'm not worried about sporadic incidents like @jasonbourne stated: a loud car or motorbike stands next to me. I think it's the same as a loud siren passing by.

Cumulative damage on the other hand is as real as it gets. You don't notice the deterioration right away, only when it reaches a certain level... :/

Unfortunately, I will have to look for an electronic motorcycle. I just don't want to risk it.

But those machines are coming up and getting better year by year. It's the future anyway

 

Thanks! I checked it, and they look nice, but pricey. I'm eyeing a brand called OX, their motorbike is around 5000 EUR.

 

I was looking at Zeros, but beyond being expensive, here's the thing: if you have a decent muffler, once you're going 50 or 60 the wind starts to overpower the engine. Wind noise is really what you have to worry about and last I checked the high end Zero maxes out around 120

 

If you think 120 is too low, there's always the LS-218 -

https://lightningmotorcycle.com/product/performance/

 

I've never done triple digits on a bike, and if I do it'll be on the back of someone else's at an actual track day. Thanks but no thanks.

I need something woodsier anyways; I put 50/50 dirt/street knobbies on last year after eating it at around 35 in some gnarly gravel S-turns. The tires I had were, in theory, 30/70, but they really didn't bite into gravel at all, and the drift over a moderately rocky turn was enough to dump me horizontal. Under the bike, of course, fortunately not dangerously so. Obnoxiously, irrationally dangerous machines. Vrrm.

 

I ride a Triumph Thruxton. You really shouldn't be worried about the noise of your bike, I did so many tests with mine measuring the decibels with an adjusted meter with different helmets and speeds. The sound of your exhausts is nothing to worry about because it travels behind you. The problem is the wind noise and the moment you go faster than 100 km/h it gets tricky for your ears (> 90 dB) so you would have the same problem with an Electric one.

Your helmet is fine but what helps even more is a neck buff which will stop the sound coming from under your helmet.

So the Bottom Line is, if you stay under 90 -100 km/h, the max dB hitting your ears would be 85 - 90 dB.

What does irritate my ears when I wear the custom earplugs is the vibrations of the bike after long rides which causes a tinnitus spike sometimes, so that might be a reason for me to try an Electric bike one day.

 

Just how fast are you riding that bike, that the sound can't catch up with you? (for reference, the speed of sound is 767 mph)

 

I understand what you mean but the sound is coming from behind you in the first place (exhaust). The moment I ride my bike faster as 50 km/h I don't hear the engine anymore, only the wind, except in a tunnel...

 

Hi @Robin21,

I just bought a bike, not a loud one (XSR125 YAMAHA with EUR5 exhaust).

As said before me, the engine is not the problem (it's "quiet", 86 dB max), it's the wind.

I saw that you have the C4 Pro. I just ordered mine (the basic one, it's the same without the communication system).

A hearing care professional also made me customs earplugs (-27 dB average, they protect better the higher frequencies: at 8 kHz it's -40 dB).

How is your riding experience now?

I currently use a LS2 Valiant II & -27 dB wax earplugs and it's not that great...
The helmet lets wind into my ears & the wax earplugs move when I ride with the heat of the body & the movement of the head inside the helmet. I really hope that the new helmet & earplugs I bought will give me enough serenity.