5pt Harness Setup
02-02-2002, 11:13 AM
#1
Nordschleife Master
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5pt Harness Setup
The previous owner installed a pair of Simpson 5pt harnesses in the car. I'm concerned about the lap belt setup and was wondering what others have used to ancher them. The outboard lap belt is bolted through the DAS roll bar into the stock seat belt mounting point and I'm assuming it is ok. The inboard belts are just through the chassis floor with a 1" washer on the underside of the car - unsafe in my opinion. I'm assuming that I'll need to weld additional bracing underneath the car where the mounting point is to make it safe unless there are other suggestions. Any idea how large (4"x4"x 1/4")? would suffice?
02-02-2002, 12:26 PM
#2
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Geoffrey,
The inboard belts in my car and many other cars I've seen are connected to the factory sealt belt mount. If you remove the factory belt latch you're left with a bracket which extends upward from the tunnel and there is a threaded hole, even though every other nut and screw is metric I believe the threaded hole is a 7/16 fine thread. Most harness kits have an eye bolt kit available to adapt to the these brackets, the outer belt would also require the same type eye bolt. The belts would then snap-in and be easily removed, just make sure you use a cotter pin on each snap mount to prevent release. The other method is to bolt the belts right to the factory mounts utilizing the same threaded holes, but I think most prefer the snap-in set up. Also make sure to use at least grade 8 or better eyebolts and hardware however you choose to mount your harness.
Good luck !
The inboard belts in my car and many other cars I've seen are connected to the factory sealt belt mount. If you remove the factory belt latch you're left with a bracket which extends upward from the tunnel and there is a threaded hole, even though every other nut and screw is metric I believe the threaded hole is a 7/16 fine thread. Most harness kits have an eye bolt kit available to adapt to the these brackets, the outer belt would also require the same type eye bolt. The belts would then snap-in and be easily removed, just make sure you use a cotter pin on each snap mount to prevent release. The other method is to bolt the belts right to the factory mounts utilizing the same threaded holes, but I think most prefer the snap-in set up. Also make sure to use at least grade 8 or better eyebolts and hardware however you choose to mount your harness.
Good luck !
02-02-2002, 04:13 PM
#3
Nordschleife Master
Thread Starter
The factory inboard seatbelt latch is connected directly to the factory seat. I replaced my seats with aftermarket ones and welded a tab on the seat bracket to hold the factory seatbelt latch. I do have the clip in belts and so the inboard eyehoop is directly in the floor. I don't think bolting it directly to the factory seatbelt latch is going to work since with the aftermarket seats there isn't much room left. Still looking for ideas.
02-02-2002, 05:57 PM
#4
Race Director
A lot of club-racing rules won't allow you to use the inner-belt attachment that hooks to the seat. The arrangement you have looks close to proper. However, the backing washer needs to be bigger. A lot of the racing places have 2x2" plates you can weld in underneath the car as a real backing plate.
02-02-2002, 09:32 PM
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I assumed you have a 911? The inner factory belt anchors are not attached to the seat, they are welded directly to top of the tunnel, just behind the e-brake. If not then Danno is right, you have to back it up with a plate, club rules will not allow attaching the harness to the seat,or seat bracket.
02-02-2002, 10:27 PM
#6
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Geoffrey,
Starting in '85 or so, the inboard seat belt mounting point was moved from the tunnel to the seat. I have an '86 with aftermarket seats. I made a bracket similar to the pre-85 factory inboard seatbelt mount and put a big (4x4ish) backing plate on the inside of the tunnel.
I made my bracket out of 1/4" steel from the hardware store and bolted it to the tunnel right behind the heater/parking brake console. It looks like a squared off "U" with the bottom of the U fastened to the tunnel. I ran 7/16-20 bolts (world seatbelt standard bolts I guess) through the factory seatbelt thingy into one arm of the "U". Then I placed the "D" for the harness lap belt over the other protruding end of the bolt and then capped it off with a nut. The nut must be safety wired. I tried a locknut (nyloc) at first but it um, came off at the track one day.
BTW: I leave the lap belts in the car permanently using "D" type ends. I don't know how much room there would be for eye-bolts. When not in use, the inboard lap belts for the harness just sit on floor behind the seats, The outer lap belt just lies on the floor next to the seat.
You can use a very large (3"?) washer for the sub belt but not for the other mounting points.
Chris
Starting in '85 or so, the inboard seat belt mounting point was moved from the tunnel to the seat. I have an '86 with aftermarket seats. I made a bracket similar to the pre-85 factory inboard seatbelt mount and put a big (4x4ish) backing plate on the inside of the tunnel.
I made my bracket out of 1/4" steel from the hardware store and bolted it to the tunnel right behind the heater/parking brake console. It looks like a squared off "U" with the bottom of the U fastened to the tunnel. I ran 7/16-20 bolts (world seatbelt standard bolts I guess) through the factory seatbelt thingy into one arm of the "U". Then I placed the "D" for the harness lap belt over the other protruding end of the bolt and then capped it off with a nut. The nut must be safety wired. I tried a locknut (nyloc) at first but it um, came off at the track one day.
BTW: I leave the lap belts in the car permanently using "D" type ends. I don't know how much room there would be for eye-bolts. When not in use, the inboard lap belts for the harness just sit on floor behind the seats, The outer lap belt just lies on the floor next to the seat.
You can use a very large (3"?) washer for the sub belt but not for the other mounting points.
Chris
02-03-2002, 09:49 AM
#7
Nordschleife Master
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I have an 89 911 Turbo so I guess that falls in with the 85 and later with the moved belt mounting location. Ok, so if I weld a 4x4x1/4" plate on the under side of the car and bolt my eyehoop through it, I should be fine for track days?
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02-05-2002, 01:25 PM
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Geoffrey:
You may also want to change the way you mount the harness straps to the DAS bar.
I removed the harness hoops on the roll bar and drilled holes in the bar and welded pipe inside to reinforce it.
Some people like it, some people prefer the loop style.
Just a thought.
Brian
1983 930 - using the mountpoints that are made into the tunnel - not on the seats. 6pt instead of 5pt.
You may also want to change the way you mount the harness straps to the DAS bar.
I removed the harness hoops on the roll bar and drilled holes in the bar and welded pipe inside to reinforce it.
Some people like it, some people prefer the loop style.
Just a thought.
Brian
1983 930 - using the mountpoints that are made into the tunnel - not on the seats. 6pt instead of 5pt.
02-06-2002, 08:48 AM
#10
Nordschleife Master
Thread Starter
Brian, Thanks for the info about the shoulder straps. In NY here, I rock climb and the "double backing" of the harness straps are exactly how we tie our rock climbing harnesses around our waist. I feel completely safe and have even taken a 20 foot fall at about 150 feet up with no problems. I would feel that drilling holes through the roll bar would weaken it. The strength of a tube is in the fact that it is supported uniformly around the circumference.