Understanding Helmets

The wearing (or not wearing) of cycling helmets is certainly a very emotive issue.  And at the end of the day, it has to be a matter of personal choice about whether you do or not, unless that is you live somewhere where the law compels you.

Many helmet advocates will tell you that you are risking severe head injury if you don’t wear a helmet.  Unfortunately there’s little empirical evidence to either back or refute this claim.  Helmet use studies, where they exist, seem to be very limited and/or biased.  But nonetheless, it’s definitely a good idea to learn as much as you can about bike helmets, so that you can make an informed decision for yourself.

Safety Standards

All bike helmets on sale in the shops have to adhere to certain safety standards.  This ensures that they all give a minimum level of protection.  Some more expensive models may offer a greater level of protection than that dictated by the standards, but equally you may just be paying a premium for the style/design elements of the helmet, and there’s no way to know either way.  There’s no scale or standard to let you compare the protection given by different helmet models.

The safety standards dictate that cycle helmets need to withstand an impact equivalent to an average weight rider travelling at a speed of 20kmph (12mph) falling onto a stationary kerb shaped object from a height of 1 metre.

Therefore, if you’re cycling along at a moderate speed and hit a pot-hole and fall off your bike, and no other vehicle is involved, then the helmet would protect your head.  However, if you’re involved in anything more serious than this, then the helmet may offer little protection at all – as the force of impact is much greater.

If you come in contact with a moving car going at 50kmph (30mph) then the helmet will only reduce the energy of the impact to the equivalent of 45kmph or 27.5mph.

Helmet Fit

It is important that a helmet should fit the cyclist correctly; otherwise the effectiveness is lost.  The helmet needs to be the of the correct size, and be placed horizontally on the top of the head, and adjusted with the straps provided to give a snug fit.

Graphic explaining how to position and fit a bike helmet correctly
Correct Helmet Positioning

If you wear the wrong sized helmet, or have it placed on the back of your head, or if you have loose straps, then you lose some of the benefit.

False Sense of Security

Studies have shown that both adults and children tend to take more risks when they cycle wearing a helmet.  They ride at faster speeds, and take more risks in traffic.

Motorists seem to take a similar view, and give cyclists wearing a helmet less clearance then those without – reducing the average passing distance from 1.3 to 1.2 metres.  And so it’s important to remember that wearing a helmet does not make you invincible against traffic.


It’s a sad fact that, when laws are passed to force people to wear helmets, rates of cycling declines.  The laws are passed in order to try and protect cyclists, but end up making it more dangerous for the cyclists that remain, and also lower the general health of the people.

It’s generally acknowledged that the more cyclists you have on the road, the safer they are.  With more bikes on the roads, governments provide more cycling facilities, and motorists are more used to seeing and responding to bikes.  Conversely, if you reduce the number of cyclists, then it becomes more dangerous.

The removal of cyclists off our streets also reduces the health of the nation.  The health benefits of riding a bike far outweigh the small additional risk that riding brings.


In a society where we look to encourage more cyclists onto the road, it doesn’t help if we portray riding as dangerous.  Encouraging people to wear helmets and high-visibility clothing makes cycling look risky, which puts people off, when in actual fact it’s no more dangerous than being a pedestrian – and we don’t ask them to wear a helmet!

The example always quoted by cycling advocates of where we should be heading is Copenhagen.  In this city almost half of all people commute to work by bike.  It has one of the best safety records for cyclists, and almost nobody wears a helmet.

More Reading


Richard Bloomfield

Richard is the founder of Dublin Bike Blog. He commutes to work every day by bike, come rain or shine, on his Dutch city bike. You can read more from Richard on his blog richardbloomfield.ie.

One thought on “Understanding Helmets

Leave a Reply

Your email address will not be published. Required fields are marked *


Because of a 2011 EU directive designed to protect your online privacy, I am required by law to check you are OK with the use of cookies on this site. more information

This site, along with almost every other web site on the internet, uses cookies (small text files) to store information about you - such as your user preferences, or whether you're logged in to the site. Any ads shown on the site will also use cookies to track your behaviour. If you're not happy about cookies, then your best bet is to disable them in your browser. If you click "Accept" below then you are consenting for cookies to be used.