did you see at the bottom of the last article.....it is not reccommended you try creating mounting points yourself unless you are a qualified mechanic because it is illegal to do so. sounds like a good system for the future but i think they have some use issues to work out.
Yep. I read that, but I don't think it's true. That article was opinion (like most automotive articles). I did spend time on NHTSA site and read a bunch of Powerpoint studies. It appears that 4-point harnesses are coming in new cars within the not too distant future. However, they are going to made into the seats and retractable at four points. You would just grab the sides, pull 'em together, and buckle. Most of the studies pointed to less fatalities in roll-overs with 4-point systems. They are coming; I'm just not sure what's available now is that much better. I really appreciate the thought I'm getting from you guys.
From the picture on the website, it appears it may uncomfortable in the chest area for a female if strapped in tight or collision. Good question and thoughts for protecting young drivers.
The same restraint system is going be available for both front seats. I'm even considering back seat 3-point retractable belts like in the newer cars. BTW, the most likely passengers for the majority of the time will be my other three daughters.
My wife, whom is very well blessed in the "chest area," doesn't like the way the 3-point comes across either. It appears the picture in my first link show that the shoulder straps can moved side-to-side on the lap belt. I suppose a woman could have the have the straps come more down the "valley" or go around the side of the "mountains."
Pros and Cons List Here's the Pros and Cons presented so far: Pros (advantages) 1. Can be adjusted to driver comfort. 2. Does not come across the neck like the 3-point belts. 3. Makes it easier for back seat access than the 3-point belts. 4. Keeps the driver and passenger in the seat more securely than the 3-point belts. Cons (disadvantages) 1. If mounted on floor behind seat, possible spinal compression 2. Some difficulty in use of getting in and out. 3. Difficulty in moving around in the seat to reach a cup or radio dial (however this is very minor - better positioned cup holders and radio remote solve those problems). Please feel free to add to either list. As you make post with additions, I will add them to this list. This is a good study.
I just read in one of the magazines (not sure which, I get Popular Hotrodding, Hot Rod, and Car Craft) and they say to keep the angle from which the belt leaves your shoulder within 10 degrees low of perpendicular. That means mounted to a bar behind the seat so that it is pretty much level with the shoulders, or at the most, angled down just a little. Again, geared mostly for racing, but if it works for racing, it will probably suffice for daily driving...
If you are going with the 4 point, you might as well add a roll bar to mount them properly. A 4 point would do the trick, and not get in the way too much about getting in and out. If you're not going to put a roll bar in, I'd say go with the factory style 3 point mounted to the door pillar. It's possible you might even find some of the vertical sliding adjusters at the bone yard you could use to make the height of the shoulder strap adjustable. Both my pickup and the PT have those, my wife needs it low because she is so short, and I have to have them set high.
I've driven (and owned) a few street cars with 4 and 5 point systems. They are really not too comfortable, if they are adjusted loose enough for you to be comfortable and have some "wiggle room," they are too loose to be completly effective in event of an accident. If they had retractors on them, that would be a different story, but those don't look like they did. Just a thought
Here is an opinion I received from a knowledgeable friend after he read what has been posted here. It doesn't necessarily offer an opinion on the use of the 4-point belts in a passenger car, but I thought it offered some insight to the NHRA rules. Everyone is quoting the mounting of the upper belts per NHRA requirements without stating the reasons for that requirement. It has to do with anchor strength. In case of an accident, the "approved" mounting method will withstand considerably more force before tearing away or shearing the mounting bolt. Less of an angle between the pulling force and the mounting tab. Pulling force is forward only. When these harnesses are mounted to the floor, the pulling force is pulling up and forward. This could possibly shear the bolt or tear the mount away. In fact, if you happen to read the SFI recommendations for building the mounting tabs themselves, they state that they should be positioned "towards the angle of pulling force". Some people weld their lap belt tabs pointing straight up when they should be angled forward 45 degrees or so. The angled tab will resist tearing forces much better. Simple mechanical engineering. These rules are written for "extreme" cases of over 100 mph in a quarter mile. Spinal compression can happen with this type of harness. In fact, spinal compression can happen with air bags and a regular three point system. It can even happen with NO belt at all. I've seen people walk away from a Jeep in a rollover accident and I've seen them carried out in a bag from a 35 mph rear ender. I still have not come to a conclusion. Heck, I stuck dead in the middle right now.
reminds me of te old saying. that's all i know is old sayings. "a little knowledge is a dangerous thing."