Lance Richert
Well-known member
Steward Mike ran a nice column in the latest Memo about the update to the Safety Belt section of the rules.
It may seem counterintuitive, but 2" lap belts in testing have shown to be better than a 3" lap belt. So the rules now allow 2 or 3 inch lap belts. The best explanation I've found comes from the Schroth web site:
"To explain why 2” webbing is more effective than 3” webbing, one needs to look at the shape of the human body. The Iliac Crest is the part of the pelvic bone that sticks out above the hips. 2” webbing fits entirely within that crest, where 3” webbing rides over the tips of the crest. The 3” webbing has less surface area by percentage than the 2” webbing which will cause more bruising on impact as “hot-spots” of force develop where the belt is making contact with the pelvic bone. Since the 2” webbing rides inside the crest it can be worn as much as 1” to 2” tighter and at the same time is more comfortable. Since the 2” webbing fits well within the Iliac Crest of the pelvis, it is less likely to slide up above the crest and cause submarining – a condition where the body slides down below the lap belt possibly causing internal organ damage. Research shows that the faster the pelvis is captured, the lower the resultant loads on the chest, head, and neck. There is no difference in the strength of the 2” webbing. All webbing (2” or 3”) must meet the same load tests."
I installed 2" lap belts in my PRO-3 car last fall, and the ease of use is better than my old 3" lap belts. More comfortable, and easier to really get nice and tight. So my observations is there are day-to-day benefits as well.
If anyone is interested in sitting in my car and trying them out, feel free to find me in the paddock. The car is a white PRO-3 car, #35.
In Mike's Steward column I only see one small mistake (though it is written correct in the actual rules). He flipped two words, and in reality polyester is preferred over nylon as a material. In fact, none of the major manufactures offer nylon as an option anymore. So if you are purchasing Simpson, Schroth, Sparco, etc. your only option is polyester to begin with.
The same manufactures that supply belts to the auto racing industry also supply to the aviation and military industries and they all spec polyester too. The nice thing about polyester is it does not nearly as much strength due to UV degradation like nylon does. It also does not lose as much strength when wet, compared to nylon.
I've given the heads up to some of the local safety belt vendors (Armadillo, Speedware) to stock 2-inch lap belts for those that are interested in purchasing them.
cheers,
Lance Richert
#35 PRO-3
It may seem counterintuitive, but 2" lap belts in testing have shown to be better than a 3" lap belt. So the rules now allow 2 or 3 inch lap belts. The best explanation I've found comes from the Schroth web site:
"To explain why 2” webbing is more effective than 3” webbing, one needs to look at the shape of the human body. The Iliac Crest is the part of the pelvic bone that sticks out above the hips. 2” webbing fits entirely within that crest, where 3” webbing rides over the tips of the crest. The 3” webbing has less surface area by percentage than the 2” webbing which will cause more bruising on impact as “hot-spots” of force develop where the belt is making contact with the pelvic bone. Since the 2” webbing rides inside the crest it can be worn as much as 1” to 2” tighter and at the same time is more comfortable. Since the 2” webbing fits well within the Iliac Crest of the pelvis, it is less likely to slide up above the crest and cause submarining – a condition where the body slides down below the lap belt possibly causing internal organ damage. Research shows that the faster the pelvis is captured, the lower the resultant loads on the chest, head, and neck. There is no difference in the strength of the 2” webbing. All webbing (2” or 3”) must meet the same load tests."
I installed 2" lap belts in my PRO-3 car last fall, and the ease of use is better than my old 3" lap belts. More comfortable, and easier to really get nice and tight. So my observations is there are day-to-day benefits as well.
If anyone is interested in sitting in my car and trying them out, feel free to find me in the paddock. The car is a white PRO-3 car, #35.
In Mike's Steward column I only see one small mistake (though it is written correct in the actual rules). He flipped two words, and in reality polyester is preferred over nylon as a material. In fact, none of the major manufactures offer nylon as an option anymore. So if you are purchasing Simpson, Schroth, Sparco, etc. your only option is polyester to begin with.
The same manufactures that supply belts to the auto racing industry also supply to the aviation and military industries and they all spec polyester too. The nice thing about polyester is it does not nearly as much strength due to UV degradation like nylon does. It also does not lose as much strength when wet, compared to nylon.
I've given the heads up to some of the local safety belt vendors (Armadillo, Speedware) to stock 2-inch lap belts for those that are interested in purchasing them.
cheers,
Lance Richert
#35 PRO-3
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