Introduction
When you are driving in harsh environments or participating in some racing competitions, you should select a restraint system which could provide a higher level of protection. Therefore, a 4-point or a 5-point harness may be the better choice in these special scenarios. These two types of harness consist of similar components, but they feature distinctive advantages and differ in the structure as well as the applications. In that case, it is significant and beneficial for you to thoroughly understand the difference between them before selecting.
What Is the Harness?
The harness consists of more attachment points compared with a general restraint system, such as 2-point and 3-point seat belts. It provides a steadier restraint for occupants.
At the same time, the harness is equipped with special designed buckle which is able to release the straps instantly. Common buckles used in harnesses involve cam-lock buckles and push-button buckles to achieve multiple straps to be released quickly.
What Is a 4-Point Harness?
A 4-point harness consists of two shoulder straps and two lap belts, and is secured by 4 anchorages. When you put on a 4-point harness, the four straps converge at the central buckle located at your waist.
Sometimes, you should consider equipping the shoulder belts of the 4-point harness with or without the retractors depending on the vehicle design and applicable regulations.
What Is a 5-Point Harness?
A 5-point harness has a similar structure to a 4-point harness but adopts an extra crotch belt, also known as an anti-submarine strap. It is secured to the seat and vehicle frame by the designated mounting points according to the vehicle structure. Likewise, the five straps are anchored to the central buckle, the same as a 4-point harness.
Typically, the 5-point harnesses are adjusted manually based on the specific applications and safety requirements.
Key Difference Between 4-Point and 5-Point Harnesses
Some people may make the mistake that the 4-point and 5-point harnesses can be used in the same scenarios, due to the comparable appearance of these two types of harnesses. However, the 4-point and 5-point harnesses are used in dissimilar applications according to their unique advantages and limitations.
Installation
A 4-point harness has one fewer strap and mounting point than a 5-point harness. As a result, it may require fewer installation steps. In contrast, you should install a crotch belt for a complete 5-point harness according to the certain routing path and the manufacturer’s instructions.
Fastening and Release
Sometimes, a 4-point harness may be relatively easier to put on or unlock based on the fewer straps and simpler buckle design. Some 4-point harnesses may be equipped with push-button buckles. It converges two straps at the buckle and attaches two additional straps to the tongue. Therefore, the harness may be easier to put on and remove.
The 5-point harnesses are commonly secured by cam-lock buckles, although some models use push-button buckles. However, an extra crotch belt must be connected to the buckle, which makes the fastening process relatively more complicated.
Restraint and Load Distribution
During an event of collision or a sudden deceleration, the occupants may move forward and their bodies can slide under the lap belt because of the inertia. This phenomenon is also called submarining. The risk depends on the harness structures, seat design, and installation.
Sometimes the waist or the internal organs of occupants may be significantly hurt when submarining occurs. The crotch belt in a 5-point harness is able to limit the unwanted excursions of occupants and reduce the risk of injury.
However, some 4-point harnesses adopt anti-submarining technologies, such as ASM systems, to reduce the risk of submarining without using an additional crotch belt.
The design of a crotch belt in a 5-point harness may not only reduce the possibility of submarining, but also better decrease the force from the restraint system during a crash or sudden braking. The chief reason is that the load from the restraint system is evenly distributed to the five straps.
In a word, the harness is able to provide a certain level of protection according to its design, seat compatibility, and installation.
Comfort and Fit
A 4-point harness may provide greater comfort for occupants because it does not have a crotch belt. Some 4-point harnesses can be equipped with retractors, which can adjust the webbing length based on your body movement.
However, the 5-point harness is commonly adjusted manually, and the webbing length remains fixed once adjusted. Moreover, some people may feel uncomfortable while putting on the crotch belt.
How to Choose Between 4-Point and 5-Point Harness
When it comes to selecting a 4-point or a 5-point harness, there are a lot of factors to consider. You should always choose a harness depending on practical use, budget, and compatibility.
Installation Compatibility
You should always choose a suitable harness which is compatible with your vehicle and seat design. Not all OEM seats are compatible with 4-point or 5-point harnesses. Therefore, it’s necessary to confirm your vehicle structure, seat position, and applicable installation conditions.
Furthermore, a poorly mounted 4-point or 5-point harness may fail to provide the intended level of protection for occupants. When installing a harness, you should pay more attention to the mounting positions, orientations, and angles of each strap. For instance, the crotch belt needs to be installed at the correct angles and webbing routing path according to the manufacturer’s instructions. Otherwise, it may fail to resist the submarining of occupants.
Application
A 4-point harness is an ideal choice for a majority of types of vehicles, such as off-road, all-terrain vehicles, and go-karts. At the same time, it is common in some motorsports and classic racing events based on the vehicle types, applicable regulations, and safety requirements.
A 5-point harness may be suitable for certain motorsports because the design of a crotch strap helps limit forward movement of occupants. However, the different levels of competition and event regulations may require a specific configuration of harnesses.
Cost
In most cases, a 4-point harness may cost less compared with a 5-point harness in the same configuration, because it has fewer components. In fact, the cost of a harness typically depends on the configuration. You are able to select a harness with or without the retractors, different types of buckles, and specific dimensions of webbing according to the vehicle design, seat positions, anchorages, and applicable regulations.
FAQ
1. Can a 4-point harness be replaced with a 5-point harness?
Not necessary. If the structure, mounting points, and seat design of your vehicles are compatible with both 4-point and 5-point harnesses, it can sometimes be replaced. A 5-point harness is not just simply adding a crotch belt to an existing 4-point harness. Meanwhile, you should check the manufacturer’s installation requirements and make sure the new restraint system is suitable for your intended use.
2. Can a 4-point or 5-point harness be customized?
Yes, 4-point and 5-point harnesses can be customized based on practical use and installation conditions. Customization options include buckle types, webbing dimensions, colors, and functional components. In most cases, manufacturers are capable of providing multiple customized and optimized solutions depending on your drawings or other specific requirements. Sometimes the modified products should be verified by several quality tests and meet safety requirements.
3. How can buyers coordinate technical changes with a harness manufacturer?
Buyers should provide the technical drawings, product specifications, intended application, and other detailed requirements to the manufacturer. After that, the expert designers will assess the feasibility of the modification and offer optimized solutions depending on your product specifications and applicable safety requirements. In addition, you can request the supplier to have a quality inspection for the modified harness and evaluate the final product.
4. Are 4-Point Harnesses Easier to Maintain Than 5-Point Harnesses?
Generally, 4-point harnesses may be easier to maintain because they have fewer straps and components. In contrast, 5-point harnesses need extra inspection for the crotch strap and its connections. However, the maintenance requirements for both 4-point and 5-point harnesses depend on their materials, operating environment, and manufacturer instructions.
Final Thought
Both 4-point and 5-point harnesses feature distinctive advantages for specific applications. Thus, you should consider selecting a suitable type to meet your restraint requirements, vehicle structures, safety standards, and intended quotation. If you attempt to purchase a harness, working with a reliable manufacturer and stating your customized demands may help you choose the products to be accommodated with your project.
DEMS is a professional seat belt and harness supplier with more than 10 years of experience in manufacturing both 4-point and 5-point harnesses. Our expert designers are capable of offering various customized and optimized solutions depending on the existing products. Moreover, the improved products will be verified by our professional testing equipment. Contact us with your demands, and we will respond within 24 hours.
