tcomeau wrote:
In each of those cases they're asking for straight down or 20 degrees back, which would put the attaching point under the seat and not serviceable/adjustable. Our seats are too low to get hardware or a wrench under them. That's why I put them in back of the seat. Whether they go straight down or backwards, it keeps the driver's torso from going forward under the lap belt. Crushed nads are better than ending up down there between the pedals. I've seen many sub belts mounted in front of the seat!
I'm new on this forum, so for those that don't know me, I have been selling racing safety equipment for over 25 years and I was NASA's first safety tech inspector. My goal is for everyone to survive any altercations they might have out there. Yes, it sucks when anyone gets hurt, so we are on the same page there.
So, as a NASA tech inspector, my reaction to the above statement is that it doesn't matter if you "can't" do it or if it won't work as you would like--what you are doing is not per the NASA rules (unless you can prove to NASA tech that the seat belt manufacturer has the configuration in their instructions). Yes, I have seen 100's if not 1000's of poorly mounted harnesses. I have seen lots of cars with harnesses mounted in front of the seat. This used to be OK per the instructions of some belt manufacturers. I have installed some this way long ago when cars were racing with stock seats. It has since been proven to be ineffective in controling the position of the lap belt.
So, yes, this makes the mounting position of the sub strap under the seat. Sometimes the seat is so low in the car that it makes it very inconvenient to install, service, inspect and adjust. Sometimes you need to be innovative on how the belts are installed and use hardware that did not come with the belts. When mounting for seats that adjust (for different drivers in an enduro for instance), you need to compromise your install. But, to mount behind the seat will have two negative effects: Your straps will be longer and thus stretch more, and, your straps will be redirected by the seat and therefore have a extra load in this area creating a place to start a tear. Both of these problems you have pointed out are bad.
I encourage you to find a different way of mounting your sub straps. This is very important as the sub straps are the first to load in an accident.
A link to the Schroth install instructions is here:
www.ioportracing.com/instructions/Competition_Instructions.pdf
As for Nylon vs. Polyester, you are correct. Nylon stretches more. There are different sides of this argument however. Stretching can be good. It dissipates energy over a longer period of time. It can be bad. It allows your body to travel further thus possible contact with your steering wheel, etc. There are other advantages and disadvantages such as how the material works with the adjusters. And, different manufacturers use different grades of the material. They all pass the tests, but some are easier to use than others. And then there is how they age. This is why the SFI has a 2-year dating period. They looked at a worst case scenario and it doesn't apply to 99% of us. Keep your harnesses out of the sun and rain and you will be OK for years.
As Big Dog points out, then there is the new harness from TeamTech. I had not seen this one before Jim pointed it out. Interesting, but I don't think I would be comfortable in this harness. Yes, it will keep you from submarining, but will it keep you down in your seat if you roll upside down? Yes, your nads are important, but my internal organs and head are more important. (I'm married, so I am not using the former anyway!) The lap belt by itself will not typically hold you down, but maybe this design will. I will have to hunt one down and check it out. Very expensive for an SFI belt, however. Might be just the ticket for those that "can't" mount the sub strap in the proper place.
For those that are going to check this harness out, the TeamTech sternum strap is not legal for NASA or SCCA club racing as you must be able to release the harnesses with one action. People have died in their burning car because a safety worker could not get the driver out after releasing their buckle due to the sturnum strap. And, if your harnesses are installed properly, you shouldn't need this device. You saw the 944 crash and burn video from the Nationals. Don't get stuck in your car--you may be unconcious and have to rely on someone else to get you out.