When it comes to selecting the ideal road cycling helmet or aero triathlon cycling helmet, the three main topics to consider to ensure that you choose the right cycling helmet are 1.) Protection and Safety, 2.) Ventilation and Breathability, 3,) Fit and Comfort.
Protection and Safety
The most important function of a helmet is to protect the rider if he or she sustains an accident. It is crucial that the outer material of the helmet is sturdy enough to protect the rider's head on impact to minimize the force to the head. Additionally, it is important that the construction on the inside of the helmet includes foam liners that are instrumental with regards to absorbing impact if the rider crashes.
Ventilation and Breathability
When selecting a bicycle helmet, one should consider the ventilation and breathability of the helmet. Most bicycle helmets are constructed with vents that channel fresh air around the cyclist's head and allow a riders head to remain cooler.
Fit and Comfort
When choosing a bicycle helmet, one should first determine the correct size helmet which can be accomplished by taking a cloth tape measure and measuring around the perimeter of the head on a plane that is level and that starts from the middle of the forehead. Once the correct size is established, one should adjust the cycling helmet so that it is not too loose and not too tight, but somewhere in the middle. Depending on the brand, different fit systems exist, but they typically allow the cyclist to adjust the helmet by rolling a dial from left to right or vice versa or by pulling or pushing levers that loosen or tighten the helmet.
Once the sizing adjustments are made, one should move his or her head from left to right and forward and backward to ensure that there is not excessive movement of the helmet or that the helmet does not feel too tight. With regards to fit and comfort, one should also consider the weight of the helmet. When riding on the bike for extended periods of time, weather, nutrition, sweat rate, and other factors can affect how a rider may feel on the bike and the last thing that a rider wants to worry about is a helmet that may feel too heavy after long hours in the saddle.