New Three Point Seat Belts

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Yadkin
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Re: New Three Point Seat Belts

Postby Yadkin » Mon Mar 19, 2018 10:03 am

njoconnor wrote:For those (like me) who are not skilled at metal fabrication, but want 3 point belt systems, there is a (somewhat) factory based solution available. If you look closely at Yadkin's pix #3 and #4, one can make out a small circular cap on the plastic inner liner. Behind that cap is a factory installed threaded receptacle for the non retracting shoulder belts used in the Euro versions of the early/mid-70's Spiders. The shoulder belts were clearly illustrated in my original manual (but not in the North American insert, which accompanied it). I also recalled that my sadly missed 71 Coupe had a 3 point system installed by the PO, with the shoulder belt anchors in roughly the same position. The factory welded receivers accept the standard mounting bolts for seatbelts.

I needed the folks at Seatbeltplanet to custom adapt a retractor which would work in any orientation (not just vertical, as most do). Since I purchased mine, I believe Sbp now has a specific model for Spiders. I needed to cut away some of the plastic liner for the retractor to clear and swivel, but it works, even with the air deflector in place. Using A/R's metal shoulder belt guides to feed the belt over the seat.

This elevates the anchor point for the shoulder belt by about 6-8 inches, but still not horizontal. It's worked for me and Patty so far. Just another approach for folks to consider.

Neil

Thanks for this post Neil. I investigated that hole previously and it looked nothing at all like a seat belt attachment. It had no threads visible, and my convertible top folds down over. In fact I thought of drilling a hole in that area below it to clear the top, then inserting a through bolt with a large washer that the Wesco provides in their kits specifically for that purpose. That's what I did in my last project. However I found the reinforced factory bolt hole under the rear "seat" so used that.

After reading your post I investigated those holes further. They are full of crud and rust which hid the depth of the hole and the threads and fooled me previously. They are, in fact, specifically for a seat belt attachment. But, with a dental pick, shop vac, WD-40 and a thread chaser should clean up nicely. In the Wesco kit are heavy angles that I can use to mount the retractor boxes directly to that hole. Although the convertible top will fold over that it shouldn't impact its use at all.

And since that reduces the angle of the belt relative to the seat guide, the vertical load on the seat frame will be reduced somewhat.

A better attachment point, thanks!

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njoconnor
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Re: New Three Point Seat Belts

Postby njoconnor » Tue Mar 20, 2018 7:54 am

Quite welcome! I've had no issues with folded top interference. The modified retractor does tend to lock up unless I pull it out sllloooowly. But, since I'm never in a rush when driving the Spider (and I'm retired!), that's not an issue. Sit and listen to the twin cam burble....

Neil
Neil O'Connor
Madison, WI
72 FIAT 124 Spider
12 Jeep Grand Cherokee Overland Summit
14 Ram 1500 Laramie Longhorn Eco-Diesel
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and a host of Audi's, Saabs, VW's, MOPAR's, Fords, and a Bimmer....

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Nanonevol
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Re: New Three Point Seat Belts

Postby Nanonevol » Tue Mar 20, 2018 8:47 am

Thank you to all the posters here. I think I'll go for the Wesco or the Seat belt planet kit. I never feel quite secure and comfortable with just my lap belt.
Yadkin, can you tell us if you got the regular or low seat sleeve for the Roadster belts?
1977 Fiat Spider
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Yadkin
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Re: New Three Point Seat Belts

Postby Yadkin » Tue Mar 20, 2018 9:58 am

Nanonevol wrote:Thank you to all the posters here. I think I'll go for the Wesco or the Seat belt planet kit. I never feel quite secure and comfortable with just my lap belt.
Yadkin, can you tell us if you got the regular or low seat sleeve for the Roadster belts?


The sleeve is 8" long.

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Yadkin
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Re: New Three Point Seat Belts

Postby Yadkin » Tue Mar 20, 2018 10:01 am

njoconnor wrote:The modified retractor does tend to lock up unless I pull it out sllloooowly.


I have these same Wesco belt retractors in my TBird and my wife, "Miss (im)Patience", gives me "the look" whenever they lock up on her. :D

DieselSpider
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Re: New Three Point Seat Belts

Postby DieselSpider » Thu Mar 22, 2018 8:49 am

Yadkin - Theory is all fine and good however there is decades of history already to show that what some have tried to caution you of has already been well proven so theory has to yield to whats been shown to be the reality. Hope you never have to find out the hard way.

I am the prepare for the worst and hope for the best type when doing these types of upgrades and the preparation for the worst in this case is with the shoulder belt retractors mounted up higher.

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Nanonevol
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Re: New Three Point Seat Belts

Postby Nanonevol » Thu Mar 22, 2018 10:56 am

Diesel, I hear the warning, what do you think of anchoring at the higher spot on the inner wheelwell behind the circular cutout?
1977 Fiat Spider
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Yadkin
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Re: New Three Point Seat Belts

Postby Yadkin » Thu Mar 22, 2018 1:51 pm

That's where I'm mounting them, on the spot that njocconer suggested. The only way to get it higher is not not use the top, or put in a roll bar.

Regards to theory, it's basic engineering statics, tension on the belt through a guide which, for the intent of a load calculation is frictionless, can only act downward in the direction of the seat frame.

rridge
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Re: New Three Point Seat Belts

Postby rridge » Fri Mar 23, 2018 11:19 am

The low position of the shoulder belt anchor on the seatback is a weakness of the Spider's design and is part and parcel of the low belt line and equally low stock seatback. There is no easy fix. If a three point belt makes your wife feel safer, that is reason enough. But do note that the seatback and its mechanism are weak and resist the idea of mounting a bar behind your head to improve anchoring. The most frequent accident in a Spider is being rear ended by someone who did not recognize the small low-slung car in front of them or failed to see the 40 year old brake lights.

SanJoseSteve
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Re: New Three Point Seat Belts

Postby SanJoseSteve » Fri Mar 23, 2018 12:14 pm

In my 72 Spider I was able to mount the retractor on the rear seat floor behind the interior trim panel behind the little quarter glass curtain. My set came with a "Shoulder Hanger" that the belt ran through. Bolting it higher up in that factory pre-drilled location on the inner wheel well caused interference with the top when stored down. I drilled a new hole about 1." below it and with an anchor plate on the exterior side of the wheel well, mounted the Shoulder Hanger there. Then I re-installed the interior rear side panel.

My 3 point belt now retracts reliably when the top is stored away and the boot cover installed. (The webbing has to exit from under the boot cover just aft of the little snap anchor to work, but once you learn where to place it when installing the boot cover, no-problem. Belt routs over the little plastic shoulder retainer I got form an 80's spider and grafted onto the upper rear corner of my seatback.

Having been in a bad rear end collision in a prior spider with only lap belts, I can tell you 1st hand that you really want that webbing across your chest. Might have saved me that ambulance ride back in 2000! Keep at it..... it can be made to work! -Steve

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Yadkin
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Re: New Three Point Seat Belts

Postby Yadkin » Fri Mar 23, 2018 8:56 pm

rridge wrote:The most frequent accident in a Spider is being rear ended by someone who did not recognize the small low-slung car in front of them or failed to see the 40 year old brake lights.


On my last restoration project I made an LED third brake light to fit inside a section of a big 'ol chrome trim that sits under the rear window. When I bought this car it has one of those chrome bar racks that bolts to the trunk lid, amazingly in good shape, and I kept it, didn't patch the mounting holes because I planned to reinstall it. So what I can do is use that for mounting a third brake light strip.

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RRoller123
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Re: New Three Point Seat Belts

Postby RRoller123 » Sat Mar 24, 2018 6:43 am

That is a really good idea, it does seem, from reading these pages for years, that the most common accident is clearly being rear ended in these little cars!
'80 FI Spider 2000
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Yadkin
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Re: New Three Point Seat Belts

Postby Yadkin » Sat Mar 24, 2018 12:02 pm

I don't like it when I get tailgated in my '64 Thunderbird Land Yacht so I want to make it as annoying as possible for dumbasses to do that behind my Fiat. They sell "attention getting" electronics to wire into an LED third brake light circuit at rapid flash when you apply the brake, then flash slower, then hold the light on until you release. I was bend someone the other day and was greatly annoyed, so that may be a good system to install in both cars.

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Yadkin
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Re: New Three Point Seat Belts

Postby Yadkin » Thu Apr 26, 2018 10:43 pm

I made a prototype bracket for proper positioning of the belt box. Each side is a mirror image of the other. The first photo is the passenger side without the box mounted. The second is the drivers side, box mounted, from the rear looking forward. This is just below the seat back. The bracket is the same width and thickness that the seat belt manufacturer uses for simple attachment angles.

What is yet to be installed is a 7/16" diameter threaded bar from the front-most hole in my bracket to the factory threaded mount at the lower rear. Same diameter as the seat belt bolts. This tension rod will be about 45 degrees from vertical and provide a direct tension path to the bracket.

I've also built a 90 degree tab on the inboard side of the brackets facing each other. These will be connected with a 1/2" diameter threaded rod, forming a trapezoidal structure with the two brackets. The trapezoid will be in compression to resist the tension loads on the diagonal bars.

Image

Image

DieselSpider
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Re: New Three Point Seat Belts

Postby DieselSpider » Tue May 01, 2018 7:32 am

That's a bit Rube Goldberg there compared to the simple straight forward way the factory mounts were made. You really want to spread the loads over a much larger area. Understand that a lot of work went into that but...


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