Safety: 3 point vs 2 point Belts?

Ok So I've been going around and around this one in my head. I have a 62 Fairlane project that I've recently started and on the road thanks to some really good friends and I've got it in my head that I definitely need belts as I have a 11 month old daughter I'd ideally like to be around for. So the question here is 2 point or 3 point? Now I've heard arguments against putting the 3 point in since these require some rather precise engineering to get them in to work safely. On the flip side I've also seen some 3 point kits out there (with some instructions found on Youtube) where a reinforcing plate was welded or bolted in and everything went in fine or so it seemed. Ideally I'd like to have the 3 point since It's kinda nice knowing that if the unmentionable happened my wife's face wouldn't be stuck in the glove box. Opinions welcomed on this.

 

I have three point belts in a 55 Ford, used the ***ist strap mount on the B pillar for the upper mount. Not perfect, but better to bump a dash than eat it.

 

I was thinking something along the lines of this:



so using your imagination here... The red dots are where ill bolt into. I probably will need to install some reinforcements which are readily available as parts to the kits im finding but you get the idea.



Again though this is potentially a bad thing though as what if the angles aren't right, you hit something and that belt rips into your collarbone doing more dammage than having kissed the dash? Is that even possible? This is a lot of if's to consider.

 

If there is some place to anchor the shoulder strap do the three point, but also check the seat mounting so the seat is bolted to the floor stronger than the seat belt anchors and don't bolt the seat belts to a car's seperate frame because if the body was to tear off the frame the seat belt might cut you in two.

 

Mid '70's GM cars (probably others) had a plastic guide clip that screwed to the top corner of the seat back to keep that shoulder belt in a favorable location.

 

i wish i had put these in my wife's mustang. a "distracted" driver crossed the road and hit her head on, she was wearing her lap belt but hit the steering wheel, face first. she hurt her lower back and has a couple scars that i think would have not happened if she had a three point harness.
if you can do it properly...DO IT.

 

Just put 3 points in 55 Chevy sedan - took a little figuring but it worked out well. But couldn't help but wonder about the liability factor

 

The liability factor is also racing around in my head too. I don't want to misplace these belts and introduce more of a safety hazard where my intentions were to lessen one.

 

Instructions here;

http://www.wescoperformance.com/retrofit-seat-belts-shoulder-mt-door.html

 

The top seatbelt mount should not be below the persons shoulder. It should be level or slightly above. If it's below that it compresses the spine.

 

I was told to also mention that I'm dealing with a hard top.

At any rate I just spoke with a guy first hand that used to work for GM as a safety engineer back in the early 90's. He said dont chance the lap belt. The problem there is a distinct potential for brain injury. As 28TUDOR mentioned so long as the the shoulder point is level or above you should be ok. This is also interesting btw... it doesn't even have to hold but lessen forward momentum you are better off than having a lap belt. Now... I just need to get that bolt above my shoulder and I should be ok. My plan is to use the plate depicted in the wesco photo. The link to wesco provided great visuals on what to expect when doing the retro fit.

Thanks guys!

 

Some of the GM seats have a shoulder strap built into the seat. They look kind of strange in to me in a hot rod. But mabey you build it into a seat so only the strap comes out the top of seat back?

 

About a 5 minutes ago I spoke with a tech at wesco... They're saying to just move the shoulder bolt back a littler further to deal with the height issue off the shoulder. I looked at pictures of my Dad's Benz convertible and they do it exactly like this. If it's good enough for Benz It should be fine in the Fairlane. Putting the belt into the seat isn't necessary. The strap that holds the belt along the seat is for positioning only. This is important though with low slung belts since keeping the belt in the proper position is essential to how it works. I think this is what I'll be ordering.

http://wescoperformance.stores.yahoo.net/convertilble-seat-belt-chrome.html

 

Just to be the devil's advocate here:

A lap belt properly mounted and used will keep your wife's face off the dash board.

Nothing to do with tradition or looks just making a statement.

 

I put three point belts in my 66 Mustang, but the top mount had one of those guides that hung down from the mounting point. The roof of the Mustang had three layers of steel in the fold, so putting a thick mounting plate behind those looked pretty secure. Fortunately, I never had to test them!

OTOH, my 68 Firebird had those multi piece GM belts so I usually only bucked the lap belt. One morning, I hit a car practically head on at fairly low speed. I was tossed forward and my head bounced of the wheel putting a nice crease across my forehead. If I had been going faster I think I might have been seriously injured. The shoulder harness would have prevented me from smacking anything altogether.

Also, keep in mind that while it primarily restrains you in the forward direction, a shoulder harness also provides some control over flopping out the window in a rollover or side impact, something a lap belt alone won't do.

 

An Interesting Read:
http://www.anapolschwartz.com/practices/seat-belt-failure/seatbelt-lap-belt-injuries.asp

 

If the body tears off the frame you're gonna be ****ed anyways.

 

Well yeah if you've gotten yourself so out of shape that the car has left the frame that goes without saying. It's the other examples pointed out up the thread that we can try to prepare for. No amount of preparation is going to cover you 100% other than staying home but I think If you can- you owe it to yourself to make your hoopty as safe as you can within reason.

I have a family I owe it to them.

 

I worked for the company making crash test dummies out here on the West Coast from '88 to '92 so I'm a bit curious who you know that I might know at GM.

I managed, ran and worked in the new product R&D and mold making department.
Having watched innumerable dummy impact tests I can tell you that if you hit that horn ****on at only 35 MPH it pushes your sternum back 4".
There's only about 5" between your sternum and your back bone.
That leaves about 1".
That's where your heart is.

 

Bob K has them installed in his '52 Chevy Convertible. I'm thinking he has the retractor mounted at the bottom of the seat on the back side and a loop at the top corner of the seat for the belt to go through and stay put above the shoulder.

 

Look around used car lots at cars that have 3-point seat belts on seats that fold forward so other can get in the back seat without hanging themselves on the front seat belts. Look at the Chrysler Sebring Conv. I bought a pair at a Pick-n-Pull. The three point belts are built into the seat. There are other 3-point seats that will fold forward. You already have buckets so look for some buckets with a 3-point seat belt arrangement. The Chrysler Sebring seats are factory seats, I'm sure they had to meet some DOT safety tests. Some pickup seats may also work.
Good Luck.

 

I guess I'm glad nowadays there's at least a little more science behind the safety features.
This 1957 Hot Rod article describes the Studebaker Hawk as having seat belts attached to the door on page 20 (bottom of column 1) , and shows a picture on page 69.
(and a picture of Honest Charley hisself on page 68)
http://www.studebaker-info.org/maa/hrm0357/hrm0357p16.html

yikes. Hot Rod rightly questions whether the Hawk's (or any 50s car's) doors will actually stay closed in a crash

I'm guessing Hot Rod's reference of anchoring belts "to the frame" may have roots to the Bonneville and drag racing tech rules of the time.
Modern rules say something similar.
http://www.landracing.com/index.php?...sk=view&id=340
"Seat belts shall be securely fastened to the frame, cross member or reinforced mounting points so that fittings are in direct line with the direction of pull. Participants are cautioned that the usual “factory” mounting through the floorboard is inadequate and will not be permitted without additional reinforcement."

It took Volvo until 1959 to make their much better anchored 3 point belt standard. (1963 in the US?)
Nils Bohlin filed the US patent in 58 for the 3 point belt. It has some details about how to mount the shoulder strap, favoring independence from the seat.
http://www.google.com/patents/US304...JIsT-4AO63IHABA#v=onepage&q=3,043,625&f=false

 

Bear-claw latches on on my list of upgrades for my '61 Suburban--I've gone around corners several times and had the doors pop open.

-Brad

 

He's actually my boss. Used to work with their safety team and CAD development back in the late 80's to early 90's. Last name of Kruper. Name ring a bell?

 

No. No bell ringing. I guess it's been too long

 

Check out Julianos web site they have quite a few how to pics and mounting idea's. Just make sure you think about when your body moves forward the angle of the shoulder belt, the mount should be above your shoulder otherwise the belt will become longer as you move forward.

 

3 point seat belts are mandatory for outside seating positions in a modified vehicle, even if the vehicle never had them installed at the factory. For what its worth I'd install them, better alive than dead. I put retractables in my '46 Olds project as well as rear child restraint mounts. They still permit centre positions as lap belts. You can colour match them these days to your trim. You can only die once.

 

I'm planing on running 4 point belts from Wesco Performance item# AM-LL- 4 point seatbelts 54.95 with free shipping

 

I think this may be the most beneficial one for you.

www.julianos.com/how2_3pt_mustang.html

 

no give in the shoulder belt is going to seem mighty restrictive.