Inexpensive retractable 3-point belts... Here's how

[sreams]

As many of you know, the pre-74 cars don't have enough room for a reel under the rear armrest. I believe the mounting points on the later cars are also configured differently.

I think I've discovered a pretty slick way to end up with retractable 3-point belts in older cars with no real modifications being necessary. I spent a total of $74 for both belts plus a few more dollars for bolts and washers. The trick was to install them upside down... with the reels on the floor. Check it out:

http://www.roadrec.com/csbelt1.jpg

http://www.roadrec.com/csbelt2.jpg

Here are the belts I purchased. They work at any angle (required for our cars regardless of where the reel is mounted):

http://www.ebay.com/itm/221039320884?ssPageName=STRK:MEWNX:IT&_trksid=p3984.m1439.l2649

I used a cutting wheel to remove the hangars. It takes a little time to get used to pulling the belt from the bottom, but it works well. I may route the belts under the seat hinge in order to avoid getting the belt twisted in the reel.

BTW... This also avoids the need for a slot at the rear seat armrest, since the seatbelt doesn't need to slide in and out at that point.

-Scott

 

[Arde]

Inverse mounting is what I did for my passenger side. I used a BMW retractable. The only weird part is that the top part has a curved sleeve that reminds you they are mounted upside down. For the driver side I kept the original non-retractable because like many have said before me you may not want to survive to witness your coupe totaled.

 

[HB Chris]

Scott,

Is your coupe a euro model? What year?

Chris

 

[sreams]

It's a '72 CS originally sold in Italy.

-Scott

Scott,

Is your coupe a euro model? What year?

Chris

 

[Stevehose]

How did you anchor them to the floor and the back seat?

 

[sreams]

I used all stock anchor points. The floor points that already exist work great... and, correct me if I'm wrong, but I think most cars have points behind the rear armrests for non-retractable belts. Perhaps the earlier 2800CS cars do not have them...

-Scott

How did you anchor them to the floor and the back seat?

 

['69 2800cs]

I did the exact same thing....my early US 2800CS has mounts for 3 points front and rear. In the rear the retractors sit on top of the parcel shelf.

It is a little weird pulling the belts with the retractor on the floor, and you can't lean forward as easily while driving, but the benefits of three point belts were worth it for me.

 

[dbower]

belts

Interesting. The shoulder belt routing over the headrest frame seems a little risky. I'm experimenting with a bracket attached to the underside of the headrest frame that should keep the shoulder belt from sliding off and maintain a route above the shoulder. In a frontal crash, you don't want a shoulder belt attached at an angle below your shoulder -- that's called spinal compression.

 

[jmackro]

In a frontal crash, you don't want a shoulder belt attached at an angle below your shoulder -- that's called spinal compression.

Very true - it's surprising how few people realize that. However, the e9 seat was never designed to bear that vertical load. Whether the belt just sits on the headrest frame, or attaches to a custom bracket doesn't change the force the seat must withstand in the event of a multi-G deceleration.

 

[sreams]

That's potentially a valid point... although it seems to me that if the force is great enough for the seatbelt to crush the seat vertically (even with the distribution of load provided by the headrest crossbar), it is probably so great that you wouldn't survive being pressed against the seatbelt with that kind of force anyway.

Besides... isn't the stock 3-point configuration (in the E9s that had it) set up the same way, with the shoulder belt going down to the same spot next to the rear seat? Is the suggestion that BMW knowingly designed a system that would result in spinal compression? Or could it be that the seats -were- designed for that kind of vertical load, because that is what would have been required with the seatbelt design BMW went with?

-Scott

Very true - it's surprising how few people realize that. However, the e9 seat was never designed to bear that vertical load. Whether the belt just sits on the headrest frame, or attaches to a custom bracket doesn't change the force the seat must withstand in the event of a multi-G deceleration.

 

[jmackro]

... it seems to me that if the force is great enough for the seatbelt to crush the seat vertically .... is probably so great that you wouldn't survive being pressed against the seatbelt with that kind of force

Yes, I don't dispute that. The e9 seats are pretty beefy, the angle of the belt isn't that great, etc. etc. I'm just pointing out that we shouldn't delude ourselves into thinking that we can make our e9's as safe as modern cars.

Is the suggestion that BMW knowingly designed a system that would result in spinal compression?

Very little was known about crash protection back in the early 1970's . Heck, this was the era when we were just evolving from simple lap belts to 3-point harnesses. And it hadn't been that long since cars had no restraints. In addition, I would bet that the US DOT's crash test standards were pretty rudimentary 40 years ago. So no, I'm not accusing BMW of being negligent relative to the standards of the day.

 

[craterface]

Don,
If the frontal crash is direct, and the belt stays across the clavicle, this would be ok, no?

Could you put some velcro on top of the headrest frame and then we some some on the belt itself, would that be ok to hold the belt in its optimal place?

I wonder the state of Volvo seat belts in 1973.

Scott

Interesting. The shoulder belt routing over the headrest frame seems a little risky. I'm experimenting with a bracket attached to the underside of the headrest frame that should keep the shoulder belt from sliding off and maintain a route above the shoulder. In a frontal crash, you don't want a shoulder belt attached at an angle below your shoulder -- that's called spinal compression.

 

[David]

On a '74, the retractor is mounted behind the rear seats (you have to remove the rear seats to get to it). The belt itself slides though a plastic guide which is mounted through the wood trim where the B-pillar would be. I always assumed this was one of the small improvements made to the '74s (although I dont know if this just for USA cars).

 

[dbower]

Don,
If the frontal crash is direct, and the belt stays across the clavicle, this would be ok, no?

Could you put some velcro on top of the headrest frame and then we some some on the belt itself, would that be ok to hold the belt in its optimal place?

I wonder the state of Volvo seat belts in 1973.

Scott

Scott: Your goal is the shoulder belt crossing your sternum and lying in a straight path from the inboard buckle to the upper outboard anchor point. In addition, the tail of the shoulder belt (behind the occupant) should be no lower than the level of the top of your shoulder, and preferably at a higher angle (just as modern belts go up to the B pillar). Hope that's clear.

Your belt path (velcro'd or not) would probably provide some protection in a low delta frontal crash. In an oblique crash, side crash or one with multiple impacts, the shoulder belt would quickly be out of position and compromised. I'm toying with a u-shaped heavy metal bracket bolted under the headrest frame to run the shoulder belt through. Not ideal but improved over my current belt path.

The ideal solution is to install a roll cage with a cross bar just above and behind your shoulders, that provides support at the proper angle for the shoulder belt. Most race cars are outfitted this way. Alternatively, you could fit competition seats that have holes in the backrest to run the belts through at the proper position. Of course, if you go this far, you'll probably want 4-point or 5-point belts and a HANS. More than most of us are willing to do.

If I recall correctly, my 72 tii had a nut welded into the roof structure behind the headliner -- specifically for attaching a front seat 3-point belt reel or slide. I installed lap/shoulder belts (factory) in the back seat of that tii using a nut that was factory-installed in the C-pillar. Also, my 69 Camaro has a nut welded above what would be the B-pillar, with a shoulder belt that is separate from the lap belt (2 buckles). Has anyone here found anything like that nut when you've had your coupe headliner out?

I am not a vehicle engineer but I do stay at Holiday Inns. This post is provided for info only and should not be construed as a safety recommendation.