Cycling Helmets — Everything You Need to Know

What to look for in a lid

By providing a shock-absorbing layer of crushable material around your head, a cycling helmet is intended to reduce the damage to your brain if you are unfortunate enough to come off your bike and hit your head. Cycling helmets have come a long way since the heavy brain buckets of the 1970s, so let's take a look at the features and details you'll find in a modern lid.

A cycling helmet comprises a thick layer that provides shock absorption, with soft cushioning for comfort where it rests on the head. The main shock-absorbing layer is almost always made from polystyrene foam, though there have been attempts to use polyurethane foam and treated cardboard.

Between the green and black sections of co-moulded outer shell you can see the shock-absorbing polystyrene

A thin plastic shell covers the foam to protect it from everyday nicks and scrapes. This shell is usually 'co-moulded' or 'in-moulded', that is, the outer shell is placed in the mould and then the polystyrene layer is formed into it.

A few helmets still have thicker hard plastic shells, which provide some shock absorption in addition to the polystyrene layer, but add weight.

The shock-absorbing layer and shell and held on the head with straps, usually made from some sort of synthetic fabric webbing and closed with a buckle.

Ventilation

Big vents in modern helmets help keep your head cool.

Since polystyrene foam is an insulator, helmets need ventilation to stop the rider's head from overheating. Early helmets simply had holes in the shell. Modern designs use channels inside the shell that allow air to flow over the rider's head.

Adjustment

Many helmets have dial adjusters to tweak the fit

For a helmet to stay in place and be comfortable, it must be adjusted to fit the wearer's head. Most helmets have some sort of cradle that is tightened or loosened via a mechanism at the rear of the helmet.

Internal reinforcement

Internal reinforcement helps high-end helmets meet standards while shedding weight

Some helmets have internal reinforcing skeletons to hold them together in an impact. This allows for larger vents and air channels, and usually a lighter helmet, but the complication of including extra components in the moulding makes such helmets more expensive.

Impact absorption standards

In the European Union, helmets must meet the EN 1078 standard, which calls for a deceleration of no more that 250g to be transmitted to the head in an impact at 5.42-5.52 m/s (a little over 12 mph). The standard involves impacts on a flat surface and a kerbstone.

In the US a Consumer Product Safety Commission (CPSC) standard applies. The two are roughly equivalent in terms of impact absorption.

In Malaysia, we set our own standards, baby! I jest, use the European approval as a guide. 

Weight

Riders prefer lighter helmets for obvious reasons. The range helmet weights tends to fall somewhere between 185 and 640 grams. Most helmets are around the 220 to 250 gram mark. 

In practice, anything under about 300g is light enough that its weight won't be annoying. But the best way is to try it on yourself to ensure your neck can take the weight. 

Price

The cheapest helmets can cost around RM50, and decently ventilated ones start from around RM100. Helmets for general use go up to almost RM300 while aerodynamic time trial helmets can easily cost over RM500.

Peaks and visors

A peak helps keep the sun out of your eyes or the rain off your glasses

Helmets intended for mountain biking often have a peak or visor, which provides a degree of shade for the rider's eyes. The styling comes from motocross, but peaks are useful on the road too. They provide shade in summer, keep the rain off your glasses in winter and annoy people who believe visors hinder your aerodynamics. 

Aerodynamics

An aero helmet will shave another few seconds off your 25-mile time trial time

Dedicated time trial specialists use helmets shaped to cut through the air, with smooth shells and long tails. Their shape has earned these helmets the nickname 'sperm hats'. They're effective if the tail is near the rider's back, but some find the effort of maintaining the right position fatiguing. Helmets with shorter, rounded tails provide most of the benefits without causing aerodynamic problems if you look down.

Giro's Air Attack was one of the first 'aero road' helmets with fewer vents for better aerodynamics
 

A recent trend is for helmets with minimal ventilation and smooth outer shells to reduce air resistance for general road racing.

Kids' helmets

Is this on right?

Helmets for toddlers carried in child seats often have little or no ventilation so they help keep junior's head warm.

For older kids, helmet design is very similar to lids for adults, with the exception that they have buckles that release if the helmet gets caught on something so the straps don't throttle the child.

Ultimately, the best way to find out if a bike helmet is right for you is to try it on. Then note down the brand and make, and go buy it online!