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Bike Helmet FAQ

Helmet FAQ-Everything you need to know

Choosing A Helmet

There many options to consider when choosing a helmet. The type of helmet you need depends directly on the type of riding you do.

Helmet Type – Sport, Road Bike or Mountain Bike

There are three basic types of cycling helmets: sport, road bike and mountain bike.

  • Sport helmets are those for multi-use, for recreational cyclists on the road or trails.
  • Road helmets are more specialized, aerodynamic, ventilated and lightweight.
  • Mountain bike helmets are also ventilated, securely fitted, and usually have visors and extra coverage around the back of the head.

One Tri carries all three types of helmets. Our most popular type is the Triathlon Aero Helmet (a type of road bike helmet), which are also called Time Trial (TT) helmets.


All helmets sold in the US, must be certified by standards set by the Consumer Product Safety Commission, since l999. The CPSC standards require standard lab testing of every helmet, including placing them on a headform with instruments and dropping them for a measured distance onto both flat and curved anvils.

Another group, the Snell Foundation also sets standards that are considered to be the highest in the industry. The foundation is a non-profit group founded in l957 after the death of a racecar driver, Pete Snell, who died from wearing an inefficient helmet. Helmets with the Snell certification have been tested for high impact and have undergone strict certification procedures in the lab, and follow up testing in the field.

Helmet standards vary in other countries, and some have less strict standards than the US. The exception are those of Australia and Canada, and New Zealand,which can be more strict than the US standards.


Helmets consist of two main parts: the liner and the outer shell. Liners are usually made of polystyrene foam that is expected to lessen the force of impact, while protecting your head. The outer shell is usually made of thermally injected plastic (polycarbonate) and some are made of reinforced resin (fiberglass) which is designed to prevent puncture resistance in addition to a smooth surface that should slide on the ground during an accident.

Some helmets also have in-mold construction where the liner and shell are fused together without the use of glue. A few other parts of a helmet include varying amounts of ventilation openings for cooling and increased comfort. Some women’s helmets have a strap for ponytails. The helmet straps should be heavier for trail riding, and lighter for road biking. Helmet accessories include various kinds of visors, reflectors, mirrors, bells and whistles.


Helmet dimensions and specifications vary by manufacturer and weight is always listed in grams. Recreational riders may not be concerned about weight, but racing helmets are designed to be much lighter. Some manufacturers have a system for adjusting the size, which is usually a sizing wheel, (Roc Lock, GPS, Acu Dial). In general, helmets usually come in small, 20” -21.75”, medium-21.75”-23.25”, and large sizes- 23.25” -24.75”. And there are extra small-below 20”, and extra large-above 24.75”. Helmets made for youth and children are much smaller sizes and range from 18”-22.5”. Women’s helmets are usually one-size-fits-all, and vary from 19.75”-22.5”.

Wearing your helmet correctly

Not all helmets easily fit on every head, so finding a proper fit is vital. There are three important things to consider: placement on the head, strap adjustment and temperature control. In cold weather, an ear band or ear muffs will help the rider stay warm. In hot weather, helmets with more air flow vents are cooler. If a helmet does not feel comfortable to the rider, some adjustments can be made, or the rider may need to switch to a different type of helmet.

Here is a checklist of rules that should be followed when fitting a cycling helmet:

  • Level – the helmet should be level on the rider’s head
  • Rim barely visible – the front rim should be barely visible to the rider’s eye
  • Y below the ear – the Y of the side straps should meet just below the ear
  • Snug strap – the chin strap should be snug against the chin, so when the rider opens their mouth, the helmet pulls down a little
  • Skin moves – if you move the helmet from side to side, the skin around the rider’s eyebrows should move slightly, if not, the helmet may be too tight, or too large.
  • Stabilizer snug – if there is a rear stabilizer, adjust it to be snug under the bulge at the back of the head
  • Palm test – have the rider put their palm on the front of the helmet and push back and up. If it moves more than an inch, more fitting is required.
  • Shake test – have the rider shake their head around and if the helmet dislodges, the straps should be adjusted

When to replace your helmet

  • after an accident (impact damage)
  • when it shows signs of wear and tear (cracks and scrapes)
  • if the helmet no longer fits your head (becomes too small)
  • generally replace a helmet after about 5 years, (UV light and weather damage)

Bicycle Helmet Law

There is currently no Federal law requiring the use of helmets for bicycle safety, however many states have laws about it. Most state laws require children below the age of 18 to wear helmets, but there are 49 all-age laws in 22 states and the District of Columbia. For more information, see Check with your city, county and state governments to find out about laws on bicycle safety in your area. Breaking helmet laws can mean paying fines.

Bicycle Terms

If you are interested in learning the lingo, here are some important bicycle terms and definitions. You’ll likely want to know what the different parts of a bike are, different trail terms, various helmet types and styles, etc.

But how effective are helmets?

The topic of helmets is a controversial one, so there are varying opinions about whether helmets should be worn or not worn. However, recent statistics support the idea of wearing helmets in order to protect against potential head, neck and brain injuries that can be fatal. For information on helmets and concussions, see this article. Here is an article arguing against the use of helmets.

Accident Statistics

A 2013 report from the Insurance Institute for Highway Safety stated that about 2 percent of all motor vehicle crash deaths are cyclists, and those deaths are from head injuries. Helmet use has been estimated to reduce the risk of head injury by 85 percent.

In recent years, only about 17 percent of fatally injured cyclists were wearing helmets.The IIHS recommends that helmets should be worn by adults as well as children.

When it comes to protecting your health (and the health of your loved ones) it’s better to be safe than sorry. Invest in a helmet and take a step towards protecting your future.

Got more questions about helmets? Email us your questions at

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