Best 3 point seat belts. Suggestions

[davepl]

Originally Posted by StingRay

The problem with washers is the sharp edge. Hardened is worse. In an impact the washer cuts and button holes through the steel. The softest most deformable washer would best if a flat washer is used. I would stack a smaller and larger diameter washer so that the outer dia. of the large diameter has the opportunity to deflect, deform and perhaps cut in less. The attached pic is the RV industry standard for a reinforcing washer in seat belt applications. Even it is not a guarantee. Best practice would put it near other structure or stamped shape and where there are multiple layers of material. The radius flange allows the washer to deform and stretch the floor without cutting. Poorly applied even they will pull through.

Not to doubt you, but the LMC kit comes with Grade 8 washers - that's what I meant by "hardened". I figured I should stick with the hardware they supply.

[StingRay]

Originally Posted by davepl

Not to doubt you, but the LMC kit comes with Grade 8 washers - that's what I meant by "hardened". I figured I should stick with the hardware they supply.

Really! You'd trust your life and those you love to LMC? Do they answer to NHTSA and Transport Canada? I do. Ask them if their installation package is tested and get them to provide documentation. It all seems so simple and logical until you watch simple and logical fold up and fall apart in a pull test. In my teenage days I too bolted buckets into my Chevelle with basic washers and bolts. I get why most think the way they do. Experience has taught me to know better.

The last pull test we did we lifted the back of the vehicle off the ground while pulling the belts. That's pulling forward at and angle about 15 degrees off horizontal and on a 3500 series van. If you think what a seat belt is required to hold is trivial think again.

As I said before seats themselves are not rocket science. The loads they and their mounts are required to withstand aren't that great. When the belts are integral it's a whole different ball game. I specifically avoid doing the same thing because in a retrofit environment the hurdles are generally more than practical to overcome. Belts by themselves aren't even bad when you understand what you are up against and have the benefit of seeing that with your own eyes. The stuff I do that passes the tests often significantly damages the vehicle structure when tested. It's a real eye opener to see a mounting point permanently deflect 3 or 4 inches and I'm generally known for significantly overbuilding my stuff.

Whenever this topic comes up I chime in with same broken record stuff and I get a lot of the same doubt about what actually needs to be done. Ive designed and tested dozens of installations over almost 20 years. Take it or leave it but the best belt installation you can do will use the factory mounting points in the 67-72 trucks. Integrated belt seats are application specific and are a poor choice for this application. Can it be done? Yes. I could do it and feel comfortable with the results and be confident that it would meet the burden of the test. Would I do it? NO I would not.

[BluTrukker]

X2 on the Morris belts. They are a bit pricey, but they fit perfect in the stock locations and work and look awesome

[jeffahart]

Originally Posted by StingRay

Take it or leave it but the best belt installation you can do will use the factory mounting points in the 67-72 trucks.

StingRay/Seat belt man, what are you running, can I see your setup.

I am running factory lap replacements on my 70. I actually purchased the three point and laps simultaneously. When they arrived I chose to keep the factory laps and sent back the three point. The three points felt cheesy. But, I will say, I would have mounted them hook or crook if they would have been a quality item.

Back in the day, no one wore seat belts. The big buckle up for safety campaign back in the 60s and early 70s was to keep people in the vehicle. My great grandfather had been thrown form vehicles twice in wrecks. Then we all stated buckling up... fast forward... my sister ran a red, in my dad's 69 XL GT, after an angry fight with her boyfriend. She was 16 she was wearing a lap belt and bit the steering wheel hard; and lost a few front teeth, she was lucky!

Man seat belts airbags and crumple zone sure have come a long way.

I still tell my wife to buckle the lap in the 70 because I don't want her falling out the door! She tends to get in and lean against the door to face me to talk.