Motorcycle helmet

Helmet Developers. He was ranked as the #1 Factory Driver for Nissan for 7 years, as well as two IMSA GTS Driving Championships and two IMSA GTS Manufacturer's Championships. Some well-known manufacturers of motorcycle helmets are:. From 1990 to 1995, the 300ZX (Z32), who was campaigned by Clayton Cunningham Racing was championed by Steve Millen in the International Motor Sports Association (IMSA) and its GT and GTS classes. Besides as protection in vehicle crashes, the full face motorcycle helmet is sometimes used in robberies and other crimes and in riots, as a mask to prevent recognition and to protect the head from injury by weapon, as at Riot control#Helmets. The VG30ET was making upwards of 800HP, with a power band that extended from 4000 to 9000 RPM. This choice is described in greater detail in the standards section. The new Electramotive (later to become NPTI) chassis was easier to work on, more robust and technically superior to the T810.

Most standard helmet tests use speeds between 5 and 7 m/s. Additional factory endorcement, combined with a new chassis, gearbox and more reliable Good Year tires contributed to the team's success. In practice, motorcycle helmet manufacturers choose the impact speed they will design for based on the speed used in standard helmet tests. From 1988 to 1989, the Nissan GTP ZX-Turbo dominated in IMSA GTP racing. So helmets help most in impacts at the speeds they were designed for, and continue to help but not as much in impacts that are at different speeds. A series of crashes attributed to tire blowouts combined with difficulty of working on the T810 chassis caused less than stellar performance both seasons. Still, a helmet with a stiffer foam that stopped the head before the liner crush space ran out would have done a better job. From 1985 to 1987, the Electramotive-developed GTP ZX-Turbo was raced in the International Motor Sports Association (IMSA) GTP class using a Lola T810 Chassis and a production-based VG30ET engine.

However, in the absence of the helmet, the head would have been brought to a sudden stop from a higher speed causing more injury. The car scored their only Trans Am win in 1986 at Lyme Rock by Paul Newman for Bob Sharp Racing. When the crush space of the liner runs out, the head will stop suddenly which is not ideal. In 1984 to 1985 showroom stock racing, the 300ZX (Z31) was a potent competitor and captured wins on numerous occasions. If the impact is faster than the one the helmet was designed for, the head will completely crush the liner and slow down but not stop in the process. From the year it was introduced, it won many comparison tests against similar Japanese sports cars such as the Mitsubishi 3000GT/Dodge Stealth and the Mazda RX-7, as well as the Chevrolet Corvette and the Porsche 968. If the helmet is in a real impact that is slower than the one for which it was designed, it will still help but the head will be decelerated a little more violently than was actually necessary given the available space between the inside and outside of the helmet, although that deceleration will still be much less than what is would have been in the absence of the helmet. It was critically acclaimed by many magazines as being a complete turnaround from the Z31, which many critics felt was a sloppy-handling GT, far from the agile, sporty 240Z of years past.

The result is that the manufacturer must choose a likely speed of impact and optimize the helmet for that impact speed. The Z32 Turbo was also Motor Trend's Import Car of the Year for 1990. It depends on the impact speed of the head, which is of course unknown at the time of manufacture of the helmet. The Z32 300ZX Turbo was on Car and Driver magazine's annual Ten Best list every year it was available, from 1990 through 1996. So how stiff is that? The answer, significantly, is that it depends. Production of the Z32 continued in Japan until 1999 through a major redesign in 1998, in naturally aspirated 2-seater, 2+2 seater, and "R" versions, which were 2+2 twin turbo models (as pictured above). This means that an ideal helmet liner is stiff enough to decelerate the impacting head to a dead stop in a smooth uniform manner just before it completely crushes the liner and no stiffer. The price of a Twin Turbo 300ZX rose to US $45,000 that year, too high for many consumers and far from the US $27,000 price it had started with.

The head cannot move any further so after crushing the liner it comes suddenly to a dead stop, causing high accelerations that injure the brain. The Z32 was discontinued in 1996 in North America due to dwindling sales figures, heightened smog regulations, and rising production costs. What happens then? Well, beyond the liner is a hard plastic shell and beyond that is whatever the helmet is hitting, which is presumably an unyielding surface. These cars had features such as flamboyant bodywork and paint and extensive performance upgrades, resulting in 460 bhp (343 kW) 1991 edition and 365 bhp (272 kW) 1995 edition. If the liner is too soft, the head will crush it completely upon impact without coming to a stop. In 1991, as well as in 1995 for the Z's 25th anniversary, Steve Millen, a famous race-car driver from New Zealand, built a limited-edition run of 300 tuned 300ZXs, known as the SMZ, through his company Stillen. This implies a limit to how soft the liner can be. Twin Turbo models featured electronically adjustable shock absorbers, and Nissan's all-wheel-steering system SUPER HICAS (Super High Capacity Actively Controlled Suspension), which could turn the rear wheels a full two degrees at speed.

Unfortunately, there is a limit to how thick the helmet can be for the simple reason that the helmet quickly becomes impractical if the liner is more than 1 or 2 inches thick. The platform was new, with a longer 97-in wheelbase and sophisticated multi-link suspension front and rear. It is clear then that it is very important that the liner in a motorcycle helmet is soft and thick so the head decelerates at a gentle rate as it sinks into it. One major difference between the VG30E(T) in the Z31 and the VG30DE(TT) placed in the Z32 was the dual overhead cam design and variable valve timing system (which was removed in 1996 to meet smog regulation). Small blood vessels are also damaged causing bleeding (petechial hemorrhages) deep within the brain. It also featured larger 245/45-16 and 16x8.5 wheels in the back as opposed to the 225/50-16 tires in front and on the NA version. This movement produces stretching and tearing of axons (diffuse axonal injury) and the insulating myelin sheath, injuries which are the major cause of loss of consciousness in a head trauma. They also came with the requisite "Twin Turbo" badging in the rear and a subtle tail spoiler, which was enlarged and redesigned in 1994.

The resulting shearing forces cause different levels in the brain to move relative to one another. The twin-turbo Z32s can be spotted with a different front bumper featuring three vents for supplying air to the dual intercoolers, as opposed to the naturally aspirated (NA) models. These forces, associated with the rapid acceleration and deceleration of the head, are smallest at the point of rotation of the brain near the lower end of the brain stem and successively increase at increasing distances from this point. Twin Turbo models were not offered as a 2+2 or convertible in the United States. In these situations rotational forces such as might occur in whiplash-type injuries are particularly important. A naturally aspirated convertible model was also introduced in 1993. Another characteristic, susceptibility to shearing forces, plays a role primarily in injuries which involve rapid and forceful movements of the head, such as in motor vehicle accidents. It featured a naturally aspirated engine rated at 222 hp, and a top-of-the-line Twin-Turbo version rated at 300 hp (224 kW) at 9.5 lbf/in² (66 kPa) of boost through two intercoolers.

Blood vessels linking the brain to the inside of the skull may also break during this process, causing dangerous bleeds. The Z32 was a complete redesign. Then the brain rebounds in the opposite direction, stretching the tissue near the impact site and squeezing the tissue on the other side of the head. Nissan replaced this very successful car with an upgraded (and much more expensive) version in 1990, dubbed the Z32 but also called 300ZX because it kept the same 3.0L of displacement. During an impact to the front of the head, the brain lurches forwards inside the skull, squeezing the tissue near the impact site and stretching the tissue on the opposite side of the head. The Z31 was in production until 1989 and sold more cars than any other Z car made to date. Think of how you lurch backwards and forwards while standing on a bus as it accelerates or stops. The Z31 was slightly restyled in 1987 due to its quickly aging design.

Closed head injury results from violent acceleration of the head which causes the brain to move around inside the skull. There were no stellar differences setting the SS apart from a regular 1988 model 300ZX Turbo except for the pearl white paint, front air dam, wheels, suspension and a viscous limited-slip differential in place of the clutch type. The most common type of head injury in motorcycle accidents is closed head injury, meaning injury in which the skull is not broken as distinct from an open head injury like a bullet wound. In 1988 Nissan released a pearl white 300ZX "Shiro Special" (AKA SS) with stiffer springs, matched shocks and no available options. Therefore, the primary purpose of a helmet is to prevent traumatic brain injury while skull and face injuries are a significant secondary concern. In 1984, the 300ZX 50th Anniversary Edition was released in celebration of the company's 50th anniversary. They frequently result in death, permanent disability or personality change and, unlike bone, neurological tissue has very limited ability to recover after an injury. There were also two special models produced.

Brain injuries are much more serious. All turbo charged models featured 3-way electronically adjustable shock absorbers. Skull fractures are usually not life threatening unless the fracture is depressed and impinges on the brain beneath and bone fractures usually heal over a relatively short period. The chassis remained somewhat similar to the 280ZX, with the same 91.3 in (2319 mm) wheelbase and MacPherson strut/trailing arm independent suspension, however the 300ZX both handled and accelerated better than the 280ZX it replaced. The common perception that a helmet's purpose is to save you from splitting your head open is misleading. In Japan, the turbo version became the highest horsepower available in a consumer vehicle on the JDM market. To understand the action of a helmet, it is first necessary to understand the mechanism of head injury. Later versions of the same engines were rated at 165 and 205 horsepower.

The purpose of the foam liner is to crush during an impact, thereby increasing the distance and period of time over which the helmet stops and reducing its acceleration. It offered V6 engines (the earilier Z-cars were all powered with an I6) for the first time in the Z chassis: a naturally-aspirated VG30E and turbocharged VG30ET, which initially produced 160 and 200 horsepower (127 and 172 kW), respectively. The purpose of the hard outer shell is. After 1984, the 300ZX was sold under the Nissan name. The conventional motorcycle helmet has two principal protective components: a thin, hard, outer shell made of acrylonitrile butadiene styrene (ABS) plastic, fiberglass or kevlar and a soft, thick, inner liner usually made of expanded polystyrene foam or expanded polypropylene foam. The Z31 chassis designation was first introduced in 1983 as a 1984 model and the third-generation Datsun Z-car. For the best protection, helmets should be replaced after any impact, and every three or so years even if no impact is known to have occurred. .

Note that impacts may, of course, come from things other than crashing, such a dropping a helmet, and may not cause any externally visible damage. It comprises the third and fourth generations of Nissan's Z-car line-up, respectively given the chassis designations Z31 and Z32. Motorcycle helmets are generally designed to break in a crash (thus expending the energy otherwise destined for the wearer's skull), so they provide little or no protection after their first impact. The Nissan 300ZX, also known as the Nissan Fairlady Z is a sports car produced by Nissan Motor Company. They generally have fabric and foam interiors for both comfort and protection. Modern helmets are constructed from plastics, often reinforced with kevlar or carbon fiber.

Some motorcycle helmets have a built-in so-called MROS (Multiple Reflective Optic System): a set of reflective surfaces inside the helmet which together function as a rear-view mirror [1]. A "novelty helmet" can protect the scalp against sunburn while riding and - if it stays on during a crash - might protect the scalp against abrasion, but it has no capability to protect the skull or brain. Such helmets are often smaller and lighter than DOT-approved helmets, and are unsuitable for crash protection because they lack the energy-absorbing foam that protects the brain by allowing it to come to a gradual stop during an impact. There are other helmets - often called "beanies" or "novelty helmets" - which are not certified and generally only used to provide the illusion of compliance with mandatory helmet laws.

All of these types of helmets are secured by a chin strap, and their protective benefits are greatly reduced if the chin strap is not fastened. The rider may thus eat or drink without unfastening the chinstrap and removing the helmet. A subset called "Convertible", "Flip-face" or "Flip-up" is also available; in these helmets, the chin bar pivots upwards (or, in some cases, may be removed). From most to least protective, they are:.

There are three basic types of motorcycle helmets. Modern standards setters choose the severity of the standard test impact to be somewhere between these two extremes, so that manufacturers are doing their best to protect the riders who can be helped by their helmet during a head impact. On the other hand, if an impact is so mild that the rider is unlikely to be injured at all so long as he is wearing a helmet than that impact is not a demanding test. If currently available data suggest that the rider is unlikely to survive in such an impact, regardless of how well his helmet performs, then there is little point in demanding that helmets be optimized for this impact.

It is possible to deduce how well the 'perfect' helmet outlined in the Function section of this page would perform in an impact of a given severity. The speeds are chosen based on modern knowledge of the human tolerance for head impact, which is by no means complete. Some of these are more severe than the impacts used in the standard tests and some are less so. Overall, there is a very wide range of severity in the impacts that could conceivably happen in a motorcycle impact.

So a perpendicular impact against a flat steel anvil at 5 m/s might be about as severe as a 30 m/s oblique impact against a concrete surface or a 30 m/s perpendicular impact against a sheet metal car door or windscreen. The sheet metal wall of a car door may bend inwards to a depth of 7.5 - 10 cm (3 - 4 inches) during a helmeted head impact, meaning that it generates more stopping distance for the rider's head than the helmet itself. The other vital factor in determining the severity of an impact is the nature of the surface struck. Of course, other surfaces are perpendicular to the motorcylists velocity such as trees, walls and the sides of other vehicles.

For example, the surface of the road is almost parallel to the direction the motorcyclist moves in so only a small component of his velocity is directed perpendicular to the road while he is riding. This confusion is relieved by understanding that the perpendicular impact speed of the helmet is usually not the same as the road speed of the motor cycle and that the severity of the impact is determined not only by the speed of the head but also by the nature of the surface it hits. At first glance, this is confusing given that motorcyclists frequently ride at speeds of 20 or 30 m/s. Most motorcycle helmet standards use impacts at speeds between 4 and 7 m/s.

drag racing, bicycling, horseback riding), and many riders in North America consider Snell certification a benefit when considering buying a helmet. The Snell Memorial Foundation has developed stricter requirements and testing procedures for motorcycle helmets, as well as helmets for other activities (e.g. Of the above standards, the DOT standard is by far the most lax. Among them are:.

Worldwide, many developed countries have defined their own sets of standards that are used to judge the effectiveness of a motorcycle helmet in an accident, and define the minimal acceptable standard thereof. In some countries, most notably the USA, there is significant popular opposition to compulsory helmet use, based on these safety and also philosophical objections (see Helmet law defense league). As with seat belt legislation the actual effects of imposing helmet wearing are a matter of dispute with evidence available indicating a risk compensation effect. These laws vary considerably, often exempting mopeds and other small-displacement bikes.

Motorcycle helmets are generally believed to greatly reduce injuries and fatalities in motorcycle accidents, thus many countries have laws requiring acceptable helmets to be worn by motorcycle riders. . The primary goal of a motorcycle helmet is to protect the rider's head during impact, although many helmets provide additional conveniences, such as face shields, ear protection, intercom etc. A motorcycle helmet is a type of protective headgear used by motorcycle riders.

Philips (scalp-like membrane to protect against rotational injury). Z1R. Suomy. Shoei (pronounced show-eh).

Schuberth. Nolan. HJC. Bell.

Arai. AGV. This is important because the foams used have very little resistance to penetration and abrasion. to provide structure to the inner liner so it does not disintegrate upon abrasive contact with pavement.

to prevent penetration of the helmet by a pointed object that might otherwise puncture the skull, and. DOT FMVSS 218 (USA). BS 6658 (United Kingdom). NZ 5430 (New Zealand).

JIS T8133 (Japan). 22 (Europe). UN/ECE Regulation No. CSA CAN3-D230-M85 (Canada).

AS 1698 (Australia).