No matter the quality or cost...
No matter the quality or cost of your racing seat and harness system, it is only as effective as your methods for mounting everything inside your race car.
Thanks to NASCAR's big push to improve driver safety in the past few years, the trickle-down effect has produced greatly improved seat and belt designs that are affordable for the Saturday night racer. For once, something besides the ever-increasing costs of racing is being passed down from the big leagues to us regular racers.
However, the quality of your harness and racing seat means little if they aren't properly installed in your race car. The idea of a seat and harness system is to hold the body with very little movement in the case of an accident. Even with the smallest race car drivers, the weight of the human body can produce tremendous inertial forces when it is allowed to move even an inch or two during a crash. For example, a 200-pound man in an accident that results in a 70g hit, which isn't unusual in racing, produces 15,000 pounds of force. To help your safety systems hold your body in place during a potentially violent crash, your seat and belts must be securely mounted in the race car and the mounts have to be in the right place. And don't make the mistake of believing you have to be on a big NASCAR-style superspeedway to require top-of-the-line safety equipment. It is actually the smaller tracks that produce the biggest hits because the turns are sharper. Because of this, when you get out of shape, the wall will come up on you more quickly. You are a lot more likely to take a hard hit into the wall at a bullring than at Daytona, where the turns are gradual.
"The most important thing when it comes to mounting your seatbelt brackets is to give your belts the opportunity to work the way they are designed," says racing seat builder Kris VanGilder, owner of Innovative Safety Products (ISP). "That means the belts should have the proper angles across your body, and they should also be in a straight line across your body."
ISP is one of the top racing seat manufacturers, providing comprehensive seating systems to race teams at every level. ISP arguably has as much sled testing experience as any private safety products manufacturer. But you may be surprised to hear that VanGilder says the greatest portion of any workday for him is spent educating racers and crew chiefs-everyone from the Cup level to the Late Model ranks-on how to properly fit and install a comprehensive restraint system. "It is that important," he says. "The best seat in the world won't do any good if the overall system isn't sound."
Notice how the mount for this...
Notice how the mount for this lap belt allows the bracket that the belt threads through to swivel. This allows the belt to be loaded evenly across the bracket in the event of an accident and greatly reduces the chances of the belt "dumping" or tearing because of all the pressure building up along one edge.
MOUNTING TO THE CAR
The primary point of emphasis when mounting your seatbelt and racing seat inside your car is that the mounts should never connect directly to the car's frame or sheetmetal. Both the seatbelt and seat should mount to a "seat hoop" that is connected to the rollcage. This way, if the driver takes a side impact that is strong enough to move the 'cage, the seat and harness will move with it. The idea is to protect the driver from being injured by his or her own rollcage.
VanGilder says that the seatbelt mounts should also allow the belt to swivel. This keeps the belt in a straight line between the mounting point and the buckle. In the event of an accident, the force of the driver's body against the belt is distributed evenly. If the seatbelt bracket cannot swivel, there is the potential for the belt to be loaded unevenly, which greatly increases the chances for equipment failure. This phenomenon is called "web dumping." It works much the same way as the old trick where it is impossible to tear a phone book in half but relatively easy if you open it and rip it along the spine. Finally, make sure to use at least a 31/48-inch or larger bolt for all your fasteners.