If you are going to go racing, safety gear is part of the entry fee. While most enthusiasts would rather spend money on a bigger carburetor or better intake manifold, basic safety gear is part of the game and necessary for your protection. As with any rules, there are right ways and wrong ways to do things and for the entry level enthusiast, the best way will eventually save both time and money while making the game of motorsports much more enjoyable.

We’ll approach this story from the National Hot Rod Association (NHRA) rules standpoint. These rules have been over 70 years in the making and often cross over into other sanctioning body safety rules. If you intend to go SCCA autocross or road racing, it’s best to spend a few moments and look up the rules for those organizations, but these safety considerations tend to be more similar than different.

This is RaceQuip’s most popular harness which is a 3-inch wide, 5-point system that includes a crotch or anti-submarine strap. These belts are rated as SFI 16.1 specifications.

Before we dive into the techniques for installation of five point safety harnesses, we will make reference to rules generated by two different safety organizations – the SFI and FIA. To quote directly from the SFI website “The SFI Foundation (SFI) is a non-profit organization established to issue and administer standards for the quality assurance of specialty performance and racing equipment.” The FIA (Federation Internationale de L’Automobile) is a similar organization but is international in scope based in France and Switzerland. These two organizations basically determine the safety standards for nearly all motorsports.

When it comes to safety harnesses, we decided to talk with Bob Mantell, the head tech guy at RaceQuip to get some facts on both the right safety belts for your application and also some tips on the correct way to install the harness.

Latch link harnesses use a simple detent latch to lock all five connections together using what is called a duckbill. Note how the shoulder belt ends are arranged with their flat areas facing each other with the crotch strap in between.

According to Mantell, the basic RaceQuip latch-link 3-inch five point safety harness represents the most popular assembly that the company sells. The harness consists of a 3-inch wide lap belt that connects to a pair of 3-inch wide shoulder harnesses along with a 2-inch wide crotch belt. The latch link system is extremely simple where all five points connect at a central location that is quickly released by merely lifting up on the latch.

An alternative to the latch link is the camlock which uses a central position where each of the belts attach. As each belt link is inserted, it snaps in place. To unlock all the belts simultaneously the user merely turns the camlock handle a quarter turn in either direction. This assembly is simple and effective and each style has its passionate supporters.

SFI 16.1 and 16.2 tags are sewn into three of the five straps of the harness. Beginning in 2017, these tags were revised and now include a date after which the belt cannot be used. SFI requires the webbing to be updated every two years. These belts are good until December of 2023, after which they will need to be replaced.

Most enthusiasts understand the need for a safety harness but also think that the current SFI spec of replacing the webbing on the harness every two years is a scam to sell more gear. However, SFI’s testing data reveals why this rule is in place. The data shows that SFI –spec nylon belt webbing tends to deteriorate rather rapidly when exposed to ultraviolet (UV) light.

We’ve included a copy of the SFI test performed in 2013 on both nylon and polyester webbing. SFI harnesses are made with nylon webbing while FIA spec harnesses are constructed of a polyester material. If you study the SFI test that we’ve included, it reveals that after four, 600-hour exposures to UV light, the nylon webbing loses 52 percent of its tensile strength, which falls below SFI’s minimum load specification.

This is a copy of the illustration in the NHRA rulebook that shows how the harness should be routed to correctly and safely position the driver in the seat. The note for the crotch strap also indicates that it should be positioned to be even with the vertical line even with driver’s chest.

The issue is that SFI and the sanctioning bodies have no idea how the belts will be used and stored during those 2 years. To err on the side of caution, the SFI must assume the worst that the belts will be exposed not just to sunlight but also shop fluorescent lights which also emit UV rays although at much lower levels.

In the report you will also notice tests on a polyester material that is the spec material required by FIA. The test data reveals that this material fares much better under the same UV light exposure tests with higher tensile strength results. This is why the FIA grants this material a five year period before it must be replaced.

Here is our harness installed in the car with the driver in place with the proper 45-degree angle on the lap harness.

It’s also important to mention that aging the webbing material also affects its ability to elongate. This is an important factor when addressing driver safety in a potential crash. Using some simple numbers, if a 200-pound driver is exposed to a 30-g impact force, this is equivalent to 6,000 pounds of force which is just below the required SFI minimum for a 3-inch wide harness assembly. Part of how a harness protects the driver is by elongation of the material which reduces the impact of instantaneous g-forces on the driver’s body. As the belt webbing ages however, the webbing becomes less flexible while also losing tensile strength. Both of these are negative factors.

While a bolt-on flat plate (left) can be used to anchor the lap harness to the floor, this may not allow the proper angle without some adjustment. An alternative approach is to use the RaceQuip snap hook ends tied to an eyelet that bolts through a reinforcement position on the floor.

This should offer at least some solid data to reinforce why the SFI requires belts to be replaced every two years. Manufacturers are required to sew SFI tags onto the belts as soon as the belts are manufactured. New SFI tags starting in 2017 have eliminated the cut-outs previously used to date the belts and now only print a date after which the webbing cannot be used in competition. SFI 16.1 and 16.2 specs do allow re-webbing where the racer can send his harness back to the manufacturer and the company can then install new webbing with updated SFI tags. RaceQuip, however, does not offer this service at this time.

Beyond the materials and requirements for replacement, the NHRA and SFI have specific requirements for how the belts should be attached to the vehicle. For example, many racers now use an eyelet bolt and quick-snap arrangement to locate the lap belt to the chassis. This is a more flexible attachment but you must use approved components available through RaceQuip. A standard short strap with a bolt hole can be used but often this flat arrangement to the floor can put the lap belt in an incorrect angle. The eyebolt and quick latch mechanism allows a certain range of angular freedom for the lap belt to attach to the floor which is helpful to achieve the recommended 45-degree angle of the lap belt to the chassis.

All SFI 16.1 and 16.2 harnesses are constructed using nylon material. This weave is designed to not only retain a minimum of 6,300 pounds of force but also stretch a given amount under impact loads to minimize the effect of the impact load on the driver.

Several other installation points are also worth mentioning. When mounting the anti-submarine or crotch strap, NHRA requires that the position under the seat be tied either to a permanent cross bar or attached to the floor with reinforced mounting and that this location be in line with the driver’s chest in the seat.

Mounting the shoulder harness is another area of concern. The most common approach is to mount the harnesses to a horizontal cross bar attached to the roll bar with no more than a 20-degree down angle between the seat and the roll bar attachment point. Do not mount the shoulder harness ends to the floor behind the driver’s seat.

This illustration will help you correctly loop a shoulder harness strap around a horizontal roll bar using a three bar slide adjuster. Starting from the right side, bring the strap under the first bar then over the middle bar and under the third bar. Continuing to the left, wrap the harness under the roll bar and back under the far left of the three bar adjuster, looping it over middle bar and under the far right bar. The last step is to loop the strap again back to the left under the far left bar. The strap should extend past the three-bar adjuster a length no less than four inches.

Just as important as the position of the shoulder harness is the wrapping technique. We’ve included a drawing of the procedure using a three bar adjuster. It may seem complex at first, but once you study the process you will see that it is actually pretty easy and will ensure the adjuster does not come loose. Plus, the proper technique will also be indicated so that a quick visual inspection will reveal if the technique has been properly executed.

This purpose of this story is not to cover all the many fine points to proper installation but rather to indicate that following all the rule and suggestions will offer the best experience and ultimately make your motorsports adventure that much more fun.

In this SFI certification test results report, a 3-inch wide lap belt should be able to withstand a minimum load of 6,300 pounds. After certifying the initial test at over 10,500 lbs, the nylon webbing was exposed to 600 hours of UV light during four sessions. When retested, the results show the nylon webbing experienced a 52 percent loss in tensile strength down to barely over 5,000 lbs, which is below the minimum required load of 6,300.