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Solo Performance Specialties - Schroth Street Legal Seat Belt Mounting Guide

Step 1, Is this the right product for me?

The first thing you might consider is whether or not the "Street-Legal" system what you are really looking for. Keep in mind that these are not approved by the SFI, and will not be accepted by any sanctioning body that requires an SFI-rated harness. Schroth originally developed these restraint systems for daily-driver use in Germany due to the inherent deficiencies of the standard 3-point harnessbelt. Popular uses include:

  • Autocrossing/Track Days: Where you are merely looking for something to hold you in your seat better, Schroth's systems fit the bill in an economical and easy-to-install manner. When you aren't tearing up the track, there is no need to remove the system as it can be disabled instantly and stays out of the way.
  • Car Shows: Some people just want to give their car a "racy" look. Again, the Schroth street system fits the bill admirably with its distinctive logo and high quality components.
  • Daily Driver Use: Schroth's system is an excellent supplemental restraint system. If you're going to use this product every day, we recommend the Autocontrol system, as it will allow you the most freedom of movement in your car.

There are some cautions to keep in mind:

  • Schroth harnessbelts should never be used by children under 12 or anyone shorter than 4'11" tall or weighing less than 88lb.
  • These harnesses are a supplemental restraint system. They are not intended for use in automobiles that never had seat belts in the first place (i.e., vintage cars).
  • There are different belts for the left and right seat. DO NOT interchange them. If the box label isn't clear, check the location of the ASM module. It should always be on the inboard side of the car.

Step 2, Availability of Mounting Points

First off, your car must have at least two accessible mounting points built into it for the lap belts, and one or two (depending on the belt model) for the shoulder belts. These points are the stock mounting points for your car's seat belts. Lap belts should always use the stock lap belt mounting points, shoulder belts can be mounted either to point "C" (the C-pillar mount for the stock rear seat shoulder strap) or to one or both "D" & "E" points (the lap belt attachment points for the rear seat.

The DOT-approved harness mounting points are the strongest mountings available in your car, and can take a tremendous amount of force (each one must withstand 3,000lb for at least 30 seconds). It is not advisable to drill and tap your own mounting points, as it is extremely doubtful that these will be strong enough. This is unnecessary anyway, as Schroth's low-profile, flexible mounting points will fit in most mounting points. Note that this means that normally you will only be able to mount your Schroth harnessbelt in a 4-seater. In some cases, a 4-point roll bar with a harness bar can provide an acceptable mounting for the Rallye Cross.

Also keep in mind that you should never, ever mount these belts to the floor behind the front seats! Apart from the weakness of the floorboards, the extreme angle means that all of the force will be transmitted to the seat back under impact. This will most certainly result in the seat back crumpling under impact and causing very serious injuries.

The B-pillar (front passenger shoulder belt) mount should also be avoided. While this mount is strong enough, the angle is to extreme for the shoulder belts to work properly. In general, the shoulder belts should be as straight as possible when viewed from above, and no more than a 45 degree downward angle when using the "D" mount.

Note that Autocontrol uses the same mountings as Rallye 3. Both Autocontrol and Rallye 3 can be mounted at point "D" (Autocontrol requires adapter). Keep in mind that in no case must you remove the stock harnessbelts or back seat. Schroth has designed their systems as supplemental restraint systems. This means that you can easily revert back to your stock harnessbelts at need without having to remove the Schroth system.

Step 3, Seat Construction

The most critical factor in the seat construction is the seat-back/head rest construction. The head rest must have some sort of gap or post to both allow the belts to pass through and to help keep the belts from going side to side. A fully integrated headrest is not acceptable .

The problem with the fully integrated headrest (far right), is that the belts tend to slide down the sides of the seat, and usually results in the driver sliding out of the shoulder straps under impact. A seat with no headrest, as pictured 2nd from the right, has no means of retaining the shoulder straps in the case of any sideways movement, and is also unacceptable.

Another factor in whether or not the seat is the right one is construction. Many seats (most notably Japanese cars, early VW's, and most Porsche stock seats) are of inferior construction and will not hold up to being used with mounting points D&E. There are two alternatives: First, you can use point "C" if that is possible for your vehicle, or you can upgrade to a higher quality seat. Contact us for more information if you are in doubt about your seat.

Step 4, Approved Vehicle List

We have an approved vehicle list that has data on many makes and models of cars. It lists approved mounting locations and whether or not the stock seats are suitable for a particular make and model of car.

While we may be able to provide harnesses for cars not on the list, keep in mind that the user assumes all risk with unapproved vehicles, and that the warranty is voided. As soon as the vehicle list is updated by Schroth (we are told that this should be in the near future), we will put it on this page.

Step 5, Tools and Experience

While we are happy to install your Schroth harnessbelts for you, there is little in the way of expertise or tools required. For all installations, you will need little more than some wrenches, a screw driver, and some pliers (preferably vise grips, to bend the tabs where necessary). You may need to remove the seat to get at the inboard lap belt point. Figure about an 45 minutes to an hour per seat for a static belt.

For the Autocontrol system, you will need a circuit tester and possibly a crimper, stripper, and some terminals (if you don't want to use the quick-connect hardware included with the kit). Included with each Autocontrol belt is a small spirit level for setting up the motion sensors. Make sure your car is on a relatively level surface. If you want your installation to look neat, you will have to move some trim and/or carpets, and expect to take 90 minutes to 3 hours (depending on how much you want to bury the wiring) per seat.

The Care and Feeding of the Schroth Restraint System

Some tips for daily use of your harness system

  • Always tighten the lap belt first. If you tighten the shoulders first, you will invariably draw the lap belt upward.
  • Make sure that the lap belt is resting firmly on your pelvis, not on the soft part of your abdomen. Failure to do this can result in internal injuries in an accident.
  • Do not wear the harness over heavy clothing, or over hard or breakable objects (pens, eyeglasses, etc.).
  • Take car that the belts do not rub on sharp objects.
  • Periodically inspect the harness for fraying or loose fasteners.
  • A common problem with new users is breakage of the adjusters when carelessly slammed in the door. Keep an extra lookout if you are new to Schroth restraints. If you do break an adjuster, we have replacement hardware that is very easy to change out available.
  • Never use the Schroth system with passengers in the rear seat, or with cargo/folded rear seats that interfere with the shoulder belts in any way.

Most of the above directions apply to regular seat belts as well. You should always keep the instruction manual in your car so that your passengers can familiarize themselves with the Schroth harnesses.

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