Differences Between Bike Helmets

Bicycle helmets certified by the Consumer Product Safety Commission protect riders from head impacts. Standard tests ensure helmet and straps survive critical stresses. Certified helmets vary widely in style and in price but even the least expensive provide this essential protection. Bicycle helmets often differ in details such as streamlining and ventilation, but some helmets designed for extreme cycling do offer head protection that exceeds CPSC standards.

Impact Resistance

Helmet impact testing involves fitting the helmet to a spherical "head" form that runs freely on a vertical testing track. Dropped from about 5 feet, the helmet undergoes multiple impacts on three different types of anvils built to represent pavement, stones, and concrete curbs. Any CPSC-certified helmet passed this impact test. That test doesn't cover all possible situations, and ventilated helmets with an open ribbed design still expose the riders to contact with smaller pieces of road debris. Off-road bike helmets tighten up the construction with a harder outer shell and less head exposure. Most touring helmets use lighter construction, ventilated for comfort. During an impact the hard foam liner compresses against the outer helmet shell, absorbing the force of the blow. Riders heal but helmets do not -- any bike helmet which took a hard hit might not protect you in another crash. Replace helmets more than 5 years old, because aging weakens the materials.

Streamlining

Elongated or tapered helmets theoretically offer less wind resistance and cut the amount of energy needed to move the bike forward. In practice the aerodynamic bike helmet only offers a slight advantage and only at high speeds. To bikers in time trials and races this matters, but for commuters and touring cyclists aerodynamics only contribute a fashion statement. Elongated helmets increase the chances of dislodging the gear in an accident, and helmets with pointed rear ribs offer snag points, which might strip away the helmet if caught on an obstacle. Rounded helmets offer excellent protection for the average rider.

Accessories

Many bike helmets come with optional sun visors made to snap off in a collision. Broken visors only add another hazard to the crash scene and many riders choose not to install them. Helmet-cams or headlamps which strap onto bicycle helmets add projection hazards. If the road impacts the accessory first, the hard object acts like a hammer against the helmet. Built-in projections on certified helmets must crush on impact and present no extra hazard. Some helmets offer built-in LED lamps, which meet CPSC standards. Helmets designed for mountain biking may include face shields for added protection against obstacles, including tree limbs overhanging the trail.

Fitting

To protect the rider, the helmet must conform closely to the shape of the skull. One-size-fits-all helmets depend on adjustable webbing to correctly orient the helmet. Helmets built in a size and shape to match the rider's head give better protection. Helmets come in designs for large and small heads, narrow or round skulls, and even include ponytail ports in the rear for those with long hair.

Children's helmets may include different sizes of pads to accommodate a growing child, but inexpensive helmets in the correct size also offer good protection. The angle of the helmet also matters -- properly adjusted the helmet sits level on the head, not tipped forward or back.