Oldssupreme

Cheerio! I知 getting ever closer to getting my 1972 supreme back running and actually driving it. Imagine that! So I知 wondering if there is a good modern vehicle with a shoulder strap system that I could find in a junkyard or online who痴 seatbelts I could easily swap into my cutlass without too much modification? I知 not even sure there would be anywhere to mount the shoulder harness anchor since there is no B pillar. Maybe I just answered my own question. I remember how unforgiving these belts were upon a hard stop and I知 not sure they are the safest compared with a modern vehicle痴 seatbelts. Has any one done this? If so what痴 involved and what would you recommend? Thank you!
chris

joe_padavano

The OEM belts were designed and tested to meet the gov't standards that were in place at the time the car was built. Inertia reel belts rely on a specific mounting and orientation of the inertia reel system to ensure the belts lock up. That usually involves design and testing effort to verify they work properly. As an aerospace engineer, I'm very nervous that such a system can be retrofitted to an older car without crash testing to verify that it works. Lacking that, you are only giving yourself a false sense of security. Personally I'll take bruises on the chest and possible broken ribs over having my head hit the windshield any day. And FYI, when the inertia reel belts do lock up, they are just as "unforgiving" as the OEM belts - otherwise they'd be worthless. The webbing stretches to absorb the load, but do the math - that's a lot of energy that the belts have to absorb and the loads where they press on your body will be high no matter what. Frankly, properly tensioned fixed belts are far more effective because they don't allow your torso to move at all, so there is less momentum to absorb. This is why racing harnesses are so tight. US drivers would balk at such a system, as it would restrict their ability to reach the phone or infotainment system.

Oldssupreme

End of discussion. Thank you so much Joe. You explained that beautifully. Much appreciated.
Chris.

RetroRanger

Morris concepts sells a 3pt retro fit belt setup for your car. IIRC its about$300 for the frontbelts

70Rocket

I have Morris three point belts in my car. They fit and work very well. I removed my fully restored belts and replaced them with the Morris belts a couple years ago. I’m glad I did.

Being a bit realistic, I haven’t seen many people wearing the second shoulder belt in these cars. They don’t allow much movement, so most people don’t wear them. And, if they are tightened properly, you really shouldn’t be able to move forward against the belt at all. Since almost no one will actually tighten the OEM shoulder belts properly, they have some slack and your upper torso will move forward very similar to an inertia reel belt.

I don’t have any safety concerns with the Morris belts. Seeing how they mount and operate, I think they are a very good alternative to the OEM, especially if, like many, you aren’t wearing the fixed shoulder belt.

The Morris belts are designed to use the factory floor and roof hard points for mounting. The belt angles are also good. Those are key points. If you don’t use the factory attachment points, then you have to look very closely at belt angles and reinforcing the mounting points.

I have installed numerous six point harnesses and have been in a number of accidents wearing them. I’ve installed them in other friends cars that also got wrecked at high speeds without injury. Understanding how those belts install and work gives me little concern over the Morris belts vs the OEM.

dc2x4drvr

^^^^^^

70Rocket

I probably should have been more clear about what I wouldn't do concerning seat belts. I would not get them out of some other junked vehicle for two reasons. First, they probably won't fit the factory anchor points correctly with the webbing either too long, too short, or with brackets that don't fit correctly. Second, the webbing degrades over time and looses strength. If you are going to convert to a three point belt system, I would buy something new that was made to fit the car with new webbing.