Bicycle helmets

How to choose and properly fit them


I’ve always found this image very funny! What’s not amusing though, is how often we encounter people wearing their helmets the wrong way.

As obvious as it sounds, an ill-fitting helmet is as good as not wearing one at all. If you’ve just learnt to ride a bike or if you’re a sensible parent getting your kids helmeted, please take the time to read this as we give you the low-down on helmets, how to choose and properly fit them.

Your helmet

The basic construction of a bicycle helmet comprises a plastic shell fused to an inner core of EPS (expended polystyrene). Aside from protecting your head from scratches, cuts and grazes, bicycle helmets work as shock absorbers for your head. In a fall, the plastic shell skids on the ground and flexes, distributing the impact energy over a larger area while the EPS in the helmet compresses and/or crushes, further dissipating the shock, preventing your brain from sloshing about in your skull.

impacted helmet

A helmet that has been subjected to an impact will never absorb another hit on the same spot and should be promptly replaced. Even if there is no visible damage, there may be hairline cracks that will prevent the helmet from functioning properly in the next crash. Some manufacturers have a replacement policy. Even if you don’t crash, most manufacturers recommend replacing your helmet every 3 years because the EPS degrades over time making it less effective. Improper handling, storage and care may also shorten a helmet’s lifespan, so treat your helmet with care – no more tossing it casually onto the ground or leaving it in the car!

Choosing a helmet

Modern helmets have come a long way in design, comfort and protection. When choosing a new helmet, first ensure it meets safety standards be it Snell, ANSI, CPSC, EU, JCF or AS/NZS depending where the helmet is manufactured and sold. Some other features to consider are:

Helmets that are deeper in the rear (similar to skateboarding helmets) offer better protection in rearward falls making them a good choice for infants and more extreme cyclists such as BMXers, dirt jumpers and mountain bikers.

Retention system
A good bicycle helmet must have an adjustable cranial band (or retention system) that tightens at the back of the head via ratchet or dial to serve as the primary means of securing the helmet to the head. Systems like this provide superior stability and greater comfort as the chin straps no longer have to be done up too tight. To do their job properly, they need to sit under the occipital lobe (the boney bits at the lower back of your head)

Pads and inner liners
There is nothing more gross than a helmet that smell like socks. CoolMax pads and linings keep heads cooler and dryer. Removable linings (usually attached by velcro) can be washed easily so they can be fresh for each ride.

Anti-insect nets
Because it is uncool to show up at a cafe post-ride with bugs in your hair. Bugs in the teeth is fine. (No, it’s not)

Front visors
Front visors are handy for keeping rain and sun out of your eyes, but will block your vision when you’re riding ‘in the drops’ on your road bike. Most are easily detachable, so this is only something to consider if you have multiple uses for your helmet.

Roll cages and Full-face helmets
Some helmets feature a strengthened roll cage with reinforced material to provide greater impact protection. Roll cages are often found on high-end road bike helmets. Full-face helmets probably offer the most protection, especially to the chin and face, which is why they are a popular choice amongst BMX racers and downhill mountain bikers.

Fitting a helmet

Now you’ve chosen a helmet, make sure it fits well. Unless its a brand and model that you are familiar with, you should always try on a helmet at a shop to ensure the best fit.

proper helmet

  1. Select your size by measuring your head at the widest diameter and matching against the manufacturer’s sizing chart:
      • It is too tight if… you feel tightness or pressure at the temples  •  it’s not hurting, but touching at some points  •  it’s unable to sit completely on the crown of your head.
      • It is too loose if… it wobbles, moves sideways, fore and aft despite tightening the adjuster dial  •  only the crown of your head touches the helmet.
      • It is a good fit if… you feel no pressure anywhere  •  it feels secure  •  it feels natural (like wearing a cap)
  2. Unfasten the chinstrap buckles
  3. Loosen the cranial band
  4. Put on the helmet, adjust the front edge of the helmet so that it rests no more than two-fingers width above your eyebrows. The helmet must protect the forehead, so please don’t wear it like a jaunty hat.
  5. Hold the front of the helmet and tighten the adjuster dial for the cranial band. The cranial band should hold the helmet securely in place with the helmet straps to back it up.
  6. The helmet straps should be snug but not tight. The ‘Y’ of the straps should meet just under each earlobe. It takes time to adjust it right, so don’t rush through it.
  7. Fasten the chinstrap buckles. you should be able to get one or two fingers under the chinstrap. It shouldn’t hang loose, but shouldn’t constrict your throat either.

Western and Asian heads

One of the most common problems with helmet fitting is that not all helmets are created equal. Helmets from western brands tend to be designed to suit oval head shapes – longitudinally longer with a narrower width compared to Asian head shapes which are close to round, with wider widths. For asians, wearing these ‘western’ helmets typically results in more space in the forehead and rear. If you’ve ever had pin-point pressure headaches from wearing a helmet, or if your helmet shifts back and forth when you ride through rough terrain, try a helmet brand that’s designed for asian heads.

asian helmet

Is a more expensive helmet better?

A more expensive helmet won’t necessarily offer better protection. It will be lighter, better ventilated and come with more style. Most modern helmets are already relatively light – 200 to 400 grams for an adult helmet. Ventilation only matters more the further and faster you ride – keep in mind that usually more ventilation means less protection. Style is probably the biggest deciding factor when searching for a helmet – lack of style prevents most cyclists (kids and adults) from wearing a helmet. Try getting a teenage cyclist to put on a helmet that doesn’t match their definition of ‘cool’; quite impossible.

Incidentally, a study carried out by Bath University revealed that car drivers leave less room when overtaking a cyclist wearing a helmet, but a much wider berth when passing a female rider with long hair. So maybe The Helmet Hair is on to something!

Not the be all and end all of cycle safety

Bicycle helmets are of the greatest use where simple falls and relatively low speeds are expected – learners, kids and mountain bikers. This is because most helmets are designed to protect the head from a fall at impact speeds of roughly 20km/h where no auto vehicle is involved. They actually have very limited capacity in crashes involving cars. In Singapore, helmet use on the roads are ‘strongly encouraged’. Cycling is not a dangerous activity, but accidents do happen. We strongly recommend that kids wear helmets whenever they cycle (and please take them off when they are not). Parents, set an example for your kids by wearing yours whenever you cycle. If you’re mountain biking, a helmet is a must!

Few would disagree that as cyclists, our basic level of protection would be to wear a helmet. After all, the brain should be smart enough to want to protect itself, right?

Images from Kabuto Helmets.