Racing Harness Installation

Last updated: January 29, 2001

Installed Harness I bought a set of Simpson Cam-lock harnesses. They are 6-point, with independent shoulder belts as required by most racing bodies. Do not get the "Y" style ones - they are illegal under some rules. (Part numbers go here.) The belts I ordered use the clip-on type ends, and clip onto eye-bolts, as opposed to the bolt-in or wrap-around types.

I had to have the shoulder belts lengthened 12" so they weren't absolutely maxed out (I am 6'2" and weigh about 210 lbs, so you may not need to do this if you are smaller). Simpson did this for free since the guy that took my order said they would fit as-is. I just had to pay postage to get them back to Simpson.

Also, the shoulder belts have a piece of webbing sewn between them (it forms an "H" out of the shoulder belts). When they lengthened them, the connector webbing between them ended up getting moved too far forward and then hit the back of my helmet, since they added length to the end that clips to the eye-bolts on the floor. So I had to send back again. Simpson again altered them for free.

While I was not entirely happy about having to mail them back and forth a few extra times and the wasted time, Simpson was very good to deal with. I would very highly recommend them. They also exchanged a helmet for free when it was too small. Great company - they have my business wherever possible.

Also, since I now know what needs to be done to the belts if you mount them the way I did, they should be able to get them right the first time. So when you order, use the part numbers I did (coming soon), and have them lengthened 12" and tell them to make sure the connector webbing between the two shoulder belts stays in the same position relative to the eye-bolt clips (i.e.- don't move them any closer to the cam lock.

I bought the eye-bolts (have to be a certain spec for most rules) from Racer Wholesale, but they ended up also coming with the Simpson harnesses (Simpson said they didn't). I also bought the 4" square backing plates for the bolts from Racer Wholesale. These also have to meet a spec for racing, which the RW ones are supposed to do.

Harness Installation

I mounted mine without a roll bar, so if you have one, some of this may apply, but the shoulder belt install will be different if they are fastened to the bar.

The following took me about 4 hours on the driver's side, but a lot of that was just figuring out how to do it. I reckon you could do it in about 1 - 2 hours if you don't make all the false starts I did - hopefully these directions will speed it up quite a bit.

On with the show:

  1. This is the worst step - the rest are pretty easy. To fasten the shoulder belts to the car, you will have to drill a hole in the rear cargo area. There will be a threaded stud sticking up from the metal deck to the right of the spare tire and in front of the silver cover plate (gas tank related?). I think this might be for the Bose tubes? (See picture below.)

    Shoulder Belt MountingJack up the car (and use the jackstands), and locate the fuel lines running from the gas tank. These form roughly a right angle heading towards the front of the car, just ahead of where the body rises up to form the rear cargo area and to the far right just inside the wheel well.

    Slip the 4" backing plate above the fuel lines. It will go if you gently pry the lines down just a bit. This is to get the plate between the lines and where you will be drilling. (Picture below.)

    Shoulder Belt Mounting - Bottom View Return to the top of the car. Get out the smallest drill bit you have, and put it in the chuck so that only about 1/4" is showing. Jodie Reynolds suggested putting masking tape over the bit so that it marks off the 1/4" you want. The bit won't cut past the tape, and it's easy to remove the tape and clean the bit later. Much better suggestion than my original one to break it off so only a 1/4" shows. Most really small bits will probably be short enough anyway so you can adjust the depth to only have a 1/4" showing.

    The reason for only having the 1/4" depth is to prevent drilling through the fuel lines in case you are off in alignment. Drill a pilot hole about 1" to the right of the stud, and exactly to the side (i.e.- align it with the stud from a front / back of the car perspective).

    Put a flashlight over the hole you just drilled so it shines through. Return to under the car, and see where the light shines through. See if it lines up with the bolt hole in the center of the 4" plate. The plate can only move about 1" side to side where it is at, so it is important to make sure it will line up.

    Redrill and re-check the pilot hole if necessary. If it is positioned correctly, drill the big hole. (I don't remember what size bit I used for the big hole - but it is easy enough to just measure it up to the eye-bolt.)

    Put the eye-bolt through the hole, and then go back under the car to put the 4" plate and washer and nut on. Clip the shoulder belts onto the eye-bolt.

    That's the hard part, it's downhill from here.

  2. Remove the two bolts holding the driver's lap belts in place. The Simpson eye-bolts will screw into the nuts welded to the car - they are exactly the right size. Screw them in, with the eyebolts through the factory seatbelts mounting hardware if you wish to retain them. (I think almost all harnesses are not DOT approved, so it is a good idea to put the stock belts back in.) Then put the washers and nuts on the bottom of the bolts where they protrude below the floorpan. (No jacking up of the car required, but helpful.) (Picture below.)

    Lap Belt Mounting Clip the harness lap belts to the eyebolts. The eye of the eye-bolt will be above the factory belt, so both belts and harnesses will go on OK.

  3. (I haven't done this yet, so...)

    Drill two holes in between the seat rail mounting bolts at the front of the seat for the anti-submarine belts. Slip the eye-bolts through, and put the 4" backing plates and nuts on from under the car.

    Clip the belts to the eye-bolts.

  4. That's it! I was going to put a harness on the passenger side as well, but can see no where to put the 4" backing plate on that side in the rear - the spare tire well is in the way. I will update when I solve this one.

Since the harnesses are not DOT approved, someone had recommended using the factory belts at the same time as the harnesses. This is probably a good idea. It would ensure you have some protection in case for whatever reason the harness install was not done correctly. (i.e.- cover my ass for legal reasons; I'm not responsible for any of the above, etc., etc.)

It would also take away the possibility of the police ticketing you for not wearing approved safety belts. That is one reason I chose to install the harness such that I could keep the factory belts. Another is that if you sell the car but want to keep the harnesses, you can simply unclip them and they are out. The factory belts stay behind - no need to re-install.


Date: Tue, 2 Dec 1997 07:27:15 -0800
From: "Pollard, Monty"

I use a 4 point Schroth belt in my 93 R1 for autocrossing. It attaches to the bolt at the left end of the shock strut. A very sturdy spot. Also, a very clean installation as the plastic tower cap still fits in place for daily use.

I believe the Schroth belts are the only ones that are actually DOT approved for street use if this is a concern.


Date: Fri, 25 Feb 2000 10:57:18 EST

Here are my comments re. harnesses.

  1. Go with a 5 or 6 point over a 4 point. w/o the submarine strap the lap belts ride up due to the tension from the shoulder straps. Not only is this relatively uncomfortable but also unsafe. In the event of an accident there is a real possibility of sliding under the belts, if you're lucky enough to not slip underneath you run the risk of cracking ribs and/or serious internal damage.

  2. Brand of belt: there are many. Sabelt, Simpson, Schroth are the 3 names that most quickly jump into my head. All three are good belts, the Schroth belts are more expensive but are the only ones that are DOT legal. What makes the Schroth belt attractive is that it incorporates a feature into the belt whereby one of the shoulder straps is doubled over w/in a plastic enclosure. Thus when you get into an accident the force of your body causes the belt to pull on the enclosure such that the plastic snaps and the belt is allowed to unfurl by an inch or so. As a result, instead of your body snapping to a hault it is allowed to decelerate a bit. Furthermore, it allows your body to slightly roll to one side which also assists in lessening the blow.

  3. Cam v. latch link: Spend the extra money and go with Cam lock belts. Cam's are much easier to get in and out of...kinda important considerations for a harness.

  4. Belt width: I recommend going with 3" belts over the 2" variety. 2" belts are not legal in most venues that require harnesses. While this may not be a consideration now it may be in the future, if you progress in the sport. The additional width greatly increases the strength of the belt...neither belt will snap, however, stretching of the belt is a consideration. Also, a 2" belt does not distribute the force over as wide an area as a 3" belt. You are more likely to break your hip bone or shoulder blade with a 2" v. 3" belt.

  5. Pull up v. pull down adjustments: I recommend pull down adjustments for the shoulder harnesses and pull ups for the lap belts. I find pull downs on the lap belts to be a pain in the butt to adjust as a result of the confined cockpit.

  6. Snap in v. bolt in: When you have the option go with the snap in, not to be too obvious here but...they allow for much more flexibility (can be removed in a snap :-)

  7. Shoulder harness mounting points...from my local time trial club rules and regs "The shoulder harnesses may not be mounted to the package shelf under the rear window [obviously n/a] and each side of the shoulder harness shall have a separate mounting point. The shoulder harness should be mounted behind the driver and above a line drawn downward from the shoulder point at an angle of forty (40) degrees with the horizontal." Obviously the best point to mount harness to a harness bar on roll bar; NEVER MOUNT THE HARNESS TO THE REAR STRUT TOWER BRACE, IT WILL NOT HOLD. If you mount it to the floor in the hatch area you must use a large backing plate, the sheet metal is not structurally sound.


>I've installed a harness in my [3] following the How-To on Steve Cirian's
>excellent site.  However, a friend with a [3] is considering using the rear
>strut tower brace for mounting the shoulder straps.  The comments below,
>recently appended to the How-To on Steve's site say this should not be done.

This is a bad idea. Tell him not to do it.

OG Racing (seems to be Porsche-focused but some good general parts too) has a harness truss that would work (on 911s) for this. It is, as the name would imply, a truss construction - think of a bridge member that is reinforced all along its length by triangulated bracing. It is certified to meet the appropriate NHTSA DOT and SAE requirements. The fact that there are these requirements makes me think it would be a bad idea to mount the harness to something that is plainly not meant to take forces acting perpendicularly in the middle of the bar. The brace is meant to handle compressive forces along its axis.



Date: Fri, 7 Apr 2000 23:26:54 -0400
From: "\(Mr\) Sandy Linthicum" (

Based on people who mount them this way for the track and crashed had this is a bad idea. On a medium hard front im it will bend 2-3 inch. Restraint sys is designed to to accound for harness belts stretching, etc. but having the mounting points (particularly the top straps anchors) move 2+ inches could kill you.

However, no problem if you use harness just to keep you in the seat firmly and use the stock belt in addition.


From: Steve Cirian (
Date: January 19, 2001

>Has anyone used a forward-facing child safety seat in a 3rd gen., and
>installed a tether bolt for additional security?  These tether bolts are
>required on U.S. 2000 models, and many manufacturers have been installing
>them for canadian models for a number of years.
>The safety seat I just purchased for my daughter has a bolt kit, and
>suggests contacting the dealer for proper location.  I thought I'd query
>this list as well.

You might be able to use the same eye bolts that I did in for the lap belts.

See above for pics and directions.

Disclaimer - I want no part of a child egetting injured, so I take no responsibility or any liability for this suggestion. You are on your own if you decide to do this.

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