The lap belts should be mounted as close as possible to the occupant to reduce belt length and insure quick belt response in side and angular impacts. The mounting angle mentioned earlier (-40 to -60 degrees) will help the lap belt stay on the pelvis during the event. This, not "dumping" (which occurs when the free end of an adjustable belt is not in line with the loaded end of the belt and can shear the webbing), is the main reason for mounting the lap belts more forward in the car. When the lap belts are mounted farther back, the angle of the belt is low. The buckle will easily rise into the abdomen when the driver starts to "sub under" in a crash. With the forward mounted belt -40 to -60 degrees from the H-point, it is harder for the buckle to rise off the pelvis and into the abdomen.
These are just a few ideas to help with belt installation. Next month, we will take on another topic as well as answer your questions concerning racing safety. Send your safety-related questions to firstname.lastname@example.org. Recognize that more research about racing safety is being done now than ever before. This testing is resulting in advancements that could help you in the event of a crash.