Straight from the horse's mouth: The SFI Foundation. SFI forms the safety standards that our equipment must meet.

I can't link directly to the harness info so follow the link above and then click on "Articles" and read up on seat belts.

First off, here's how to properly position all the belts when installed in the vehicle. When I go to race events I see these rules violated all the time and that suprises me. The belts are there to save your life. Life is worth taking the extra time to install belts correctly.



Notice the allowable angle of the shoulder belts. I see this violated constantly. Also read up on why you need a sub strap. It's not to keep you from sliding into the floorboard (the lap belt does that when installed properly), it's to keep the latch assembly from being pulled up towards your abdomen when the shoulder belts are straining.

 

the FIA rules are pretty comprehensive about how to mount the harness. i use them whenever the SCCA GCR leaves me hangin. check it out: http://www.fia.com/regle/REG_TEC/Ann...xtes/253-a.pdf they go very in depth, good reference for other parts too (like seats and window nets).

i agree too, i see all kinds of stupid setups at DE's and races. i like to think of it as natural selection at its finest...

 

Mounting seatbelts wrong isn't nearly as bad as having a harness without a bar or cage. You're worse off just having a harness without a cage/bar than you are with your stock belts.

 

I wonder if Dale Earnhardt would agree with that.

The two most important things to consider when mounting safety equipment in a car are in no order:

The rules of your sanctioning body

The installation instructions from your equipment manufacturer.

 

I think Chris's point is that without a roll bar or cage the harness keeps the driver firmly in the seat while the roof caves into his head if the car were to roll over at high speed.

 

Good stuff. Also something to think about. Your seat should be mounted to either the chassis or the cage, not both. If you wreck, you dont want the seat being twisted if the cage goes one way and the chassis goes another. Same with the belts. I've heard of shoulder harnesses going slack cause they were mounted to the roll cage and the lap and sub were mounted to the chassis, and the impact caused them to move seperately. Any opinions? I'm working on a "tub" seat mount that is only attached to the cage. This will also allow me to mount the lap and sub belts to it, keeping everything attached to the cage and nothing the chassis.

 

There was an interesting article in Sportscar a while back about the degradation of the harness belts in the sun, which is also important. UV does a real number on the nylon webbing, and black webbing suffers the most(absorbs everything), while blue webbing suffered least (bounces blue including some of the UV) There is also polyester webbing similar to your stock belts which lasts a long time, but it does not stretch as much in a collission, so the crash impulse isn't spread over as long a time interval as it would be with the nylon.

 

I remember that article, Gene. Seems there was a graph that showed webbing strength and it really plummeted after about 20 months or so IIRC. It was pretty amazing...

 

I thought they said that the polyester stretched more?

 

Gene and DamonB

Regarding the degradation of nylon 6-6 over time, SFI's website has an article similar to what you are talking about...

http://www.sfifoundation.com/seatbelt.html

(Strangely enough,...isn't this the same material that Jimlab's unobtainium bushings are made from?)

http://www.sfifoundation.com/nylon.gif

 

Jim's bushings are nylon but I am sure they will last almost forever. Harnesses are made of small fibers and loaded in tremendous tension in a crash. The bushings are solid parts that are mostly loaded in compression.

 

True.

 

Plus the bushings aren't exposed to the sun the way your seatbelts are...