by Bruce Tharp

The purpose of the X-O SKELETON helmets is to provide mountain bikers with a helmet that was designed specifically for their needs. Road biking and mountain biking are very different in their personality, conditions, and requirements; yet, the helmets on the market are interchangeable and have not fully responded to the emergence and dominance of this sport. 93% of all bicycles sold in America are mountain bikes, and only 10% of all bikers wear helmets despite that head injuries are the leading cause of death within the sport. How can wearing a helmet while mountain biking become more desirable?

The user benefits with a helmet that is more protective in many crash scenarios, cooler on the head, as light--if not lighter, and as easy to use, while still conforming to the aggressive nature of the sport.

In addition to the functional advantages of the form, the helmet is aesthetically consistent with the personality of the brash, adrenaline-rich sport. While "road" biking relates to the man-made, "mountain" biking is about nature; and, it is from this difference that the form was developed. It was inspired by nature's different solutions to protection (as with its namesake, the exoskeleton) found in poisonous caterpillars, cacti, alligators, sea coral, snapping turtles, poisonous frogs--plants and animals with attitude. The models pictured show an example of the breadth of geographical appeal and choice for the user: the Southwestern GILA MONSTER and a jungle's POISON ARROW FROG. The CITY RAT is directed at the urban market because mountain bikes are quite prevalent in the cities due to their durability. In addition, the stimulus of fighting dense traffic, manhole covers, cab drivers, construction, and pedestrians is nearly equivalent to that found on rough trails when mountain biking.

More people will use helmets and protect themselves as a result of this design. The visual and functional attributes will appeal even to the type of bicyclists who feel too tough and defiant for traditional road helmets--the X-O SKELETON too has a tough, defiant personality. As well, more people will be more comfortable engaging in healthy, outdoor, recreation as a result of the improvements in a helmet designed specifically for mountain biking.

Traditional helmet design focuses primarily on aerodynamics and forced convection (cooling air flow through the helmet), since the weight reduction seems to have bottomed-out with most new helmets ranging from only 6-9 ounces. The aerodynamics are of little concern to mountain bikers (especially to the vast majority who do not race) due to the nature of the sport--a greater percentage of time is spent riding slowly (or even carrying) the bike uphill than during the quick descents. Traditional helmets focus on creating channels for air to move in through the front of the helmet, over the head, and out the posterior. The effectiveness of this depends greatly on a static head position, more characteristic of road biking. The design problem is how to address the different conditions of mountain biking, while making the helmets as protective, lightweight, and cool.

The manufacturing process and materials are very similar to present production--molded polystyrene soft-shell models and hard-shell models which use a vacuum-formed polystyrene cover. The innovation of the design solution lies in the redefinition of the form. A greater dissipation of heat from the user's head is accomplished by the greater number and evenly distributed ventilation holes. As well, air disturbance created by the helmet's protrusions also increases cooling convection even at low speeds and regardless of head position. The protrusions also allow for a greater volume of shock absorbing material between the point of impact and the head. A greater overall strength-to-weight ratio is achieved through the network of concave connections between the protrusions. The rough surface treatment hides more wear and tear (scratches from branches, etc.) before becoming visually unappealing.

The greatest ecological benefit comes from the extended life of the helmet. This is due to the visual durability (to scratches and other surface marks) and strength durability. This is more apparent with the less popular soft-shell models that users complain of becoming too damaged looking too soon. The popularity of soft-shells would reduce the need for a hard shell (less manufacturing material and processing) that adds weight and does not increase overall strength of the helmet. Also, with a greater strength-to-weight ratio less material is needed. In addition, these helmets would be sent by the user back to the manufacturer for a rebate if the helmet is involved in a collision. Damaged helmets, along with the crash conditions, are very valuable in the research and development of better performing helmets.