New research carried out recently by a leading manufacturer of earplugs for motorcyclists has determined that riding a motorbike at 70mph can cause permanent hearing damage after just four minutes.

Guildford based Auritech worked in collaboration with the University of Southampton to calculate the sound pressure level (noise) a motorcyclist is exposed to when riding their bike.

Riding a standard Yamaha Tracer 900 at Leicestershire’s Bruntingthorpe Proving Ground, and with the rider wearing a HJC RPHA 70 crash helmet, technicians from the university placed tiny microphones by the rider’s ears to record and analyse the wind noise generated while riding at a variety of controlled speeds.

The results showed that riding at a steady 50mph generated 92.7 decibels (dB) of wind noise, enough to cause permanent hearing damage after less than 26 minutes. At 60mph, the reading went up to 97.9dB (eight minutes), while at 70mph the noise levels went to over 100dB, risking damage in just four minutes. At 90mph, the university’s experts considered that irreversible hearing damage could occur in under 90 seconds.

To validate their results, and to test the theory that some helmets were quieter than others, the scientists also carried out the test using different styled helmets, finding that while there was a tiny amount of variance, no helmet reduced the noise levels significantly.

Further tests did show that changing the Tracer’s screen made the biggest difference when it came to reducing noise levels, with Yamaha’s larger accessory ‘Touring’ screen making the biggest difference to reducing wind noise. With the touring screen fitted, the noise pressure reduced from 100.8dB to 92.4dB, a level at which scientists estimate a rider can be exposed to for 27 minutes at 70mph before risking permanent hearing damage.

Noise Induced Hearing Loss (NIHL) usually starts in the form of tinnitus, a permanent ringing in the ears for which there is no solution. Continued exposure to unsafe noise levels can ultimately lead to deafness, which is why motorcyclists are advised to wear ear plugs in order to protect their hearing.

While cheap disposable ear plugs do a good job in blocking out all sounds under the helmet, specialist plugs, such as those made by Auritech, are designed to filter out the harmful high frequency sounds while allowing helpful low frequency sound (such as speech, traffic noise and exhaust tones) to be heard.

Commenting on the research carried out, Wendy Faulkner from Auritech said: “We’ve carried out research into this area before, but this time we wanted to try out a number of different combinations of helmets and screens, to see what impact that has on the rider’s exposure to harmful wind noise.

“Despite there being some small variations between the different combinations, no helmet or screen protected the rider from the dangers of wind noise. No combination reduced the exposure to anywhere near 85dB, which is the level at which the Health and Safety Executive determines that hearing protection must be provided in the workplace, and which confirmed that it is strongly advisable for motorcyclists to wear ear plugs while out riding in anything other than slow speed.”

Additional research by Auritech, carried out last year, has determined that around 60% of British riders regularly ride without wearing earplugs, with 17% of those surveyed saying that they were unaware of the risk of damaging their hearing, while two thirds of those who responded to the survey said that they didn’t wear protection as they wanted to hear their surroundings.

Filtered protectors, like Auritech Biker earplugs, still allow the rider to hear external sounds like traffic, exhaust notes and intercoms, while being tuned to block out harmful high frequency wind noise.

Typical noise levels for everyday activities