Technology

Technology and motorsport are virtually synonymous. Our philosophy of motorsport safety extends the engineering and development common in other parts of motorsport to the safety equipment systems. This include everything from the Helmet to your racing boots, but we specialize in the harnesses, helmets, and racing seats that we sell.

ECE-R 16.04 / DOT-FMVSS 209

SCHROTH street legal harness belts are unique in their ability to be installed to factory provided mounting points along with the factory provided seat belts. SCHROTH harness belts meet all certification requirements by the German TÜV, ECE-R 16.04 and US-DOT FMVSS 209 for use on public roads. Each belt comes with complete installation and operating instructions. If your vehicle is listed in the included Vehicle Reference List the installation has been tested and appoved with the stock seat or the listed aftermarket seats.

SCHROTH QuickFit harnessbelts have the make and model of the applicable car printed on the tail strap label.

Unlike most other aftermarket harness belts, most SCHROTH street legal harness belts have a unique disconnect feature between the front part of the harness and the rear tail strap. When you are not using the SCHROTH street legal harness belts, they can be stored out of the way allowing complete access for all passengers and full use of all factory seat belts.

RFR Buckle

The patented SCHROTH RFR™ rotary (cam lock) buckle operates with a carbon fiber reinforced gear system. Since it operates grease free it is insensitive to dust and other environmental influences. RFR™ the abbreviation for Regressive Force Release, means the release force is reduced during release operation rather than increasing as seen with all other rotary buckle products. Therefore the RFR™ buckle meets the stringent FIA required release forces without the need of an extended lever. The patented actuator with the recessed lever helps to avoid the risk of accidental release. The durable RFR™ rotary buckle is approximately 30 percent lighter than other products, yet it is still one of the strongest in the market. For FIA and ECE-R 16.04 (street legal) approved racing harnesses (FE models for Rally driving) it is available as a push button type buckle.

2" Lap Belts

To explain why 2" webbing is more effective than 3" webbing, one needs to look at the shape of the human body. The Iliac Crest is the part of the pelvic bone that sticks out above the hips. 2" webbing fits entirely within that crest, where 3" webbing rides over the tips of the crest. The 3" webbing has less surface area by percentage than the 2" webbing which will cause more bruising on impact as "hot-spots" of force develop where the belt is making contact with the pelvic bone. Since the 2" webbing rides inside the crest it can be worn as much as 1" to 2" tighter and at the same time is more comfortable.

Since the 2" webbing fits well within the Iliac Crest of the pelvis, it is less likely to slide up above the crest and cause submarining - a condition where the body slides down below the lap belt possibly causing internal organ damage.

Research shows that the faster the pelvis is captured, the lower the resultant loads on the chest, head, and neck. There is no difference in the strength of the 2" webbing. All webbing (2" or 3") must meet the same load tests.


ASM® Anti Sub Marining Technology

The patented SCHROTH asm® system offers an unique safety advantage for 4-point harnesses. asm® is the acronym for anti submarining. The risk to submarine (sliding underneath the lap belt), a well known phenomenon during frontal impacts, is significantly reduced by the asm® safety system. The energy converter is located in one of the shoulder belts. Severe injuries or death are possible using 4-point harnesses without the SCHROTH asm® safety system or an anti-sub strap. SCHROTH harnesses designed for use on public roads (FE push button models) or those likely to be used as 4-points come with the asm® safety system. The performance of the SCHROTH asm® safety system has also been positively tested in conjunction with airbags.

Current Head And Neck Supports (HANS®) provide further reduction of head deceleration and neck bending.

The asm® system on all SCHROTH Rallye and QuickFit belts - excluding the new QuickFit Pro - is not compatible the with HANS®. Only belts having a center RFR Cam lock can be used with HANS®.

We recommend that only non asm® belts be used in competition harnessbelts.

Racing harnesses without asm® must be worn with an anti-sub strap!

Webbing Longevity

Webbing that makes the difference!

The webbing we use is especially designed and manufactured for SCHROTH. Each lot manufactured must pass our stringent quality control procedures. SCHROTH only uses Polyester material. Polyester has advantages over Polyamide (NYLON®) webbing. Advantages, such as lesser degradation under light (see figure 1) and a resistance against acids like battery acid. In addition Polyester does not absorb moisture so the performance of SCHROTH harnesses do not change whatever the climate may be.

Polyester also has a better force/elongation ratio so a well designed webbing can convert more energy during an accident.

Webbing Construction

Unique to SCHROTH is the 'memory effect' we have designed into our webbing. Special mono filaments laterally woven in, perform like small leaf springs and keep the webbing flat. This results in better load spreading over the full width of the SCHROTH webbing. An additional advantage of the SCHROTH webbing: The special weaving technology forms round edges for additional comfort.


Hybrid Style Restraints

Engineering in Action!

Typical Formula (D-Ring) restraints display high upper torso trajectory during a crash. To reduce this trajectory, the crotch straps have to be routed backwards and to be worn extremely tight. Some drivers complain of reduced blood flow in their legs. In addition, this configuration does not help during a rear impact to keep the buckle and the lap belt in the correct position. In particular in typical open-wheel race car seating positions the driver is not kept firmly in his seat but is likely to move up exceeding the roll over protection bar.

The so called T-bar 6-point belt design provides a better restraining function since the anti-sub straps can be routed downward following approximately a chest/crotch tangential. This keeps the buckle in place and provides direct load transfer from the shoulder straps into the anti-sub straps. During a rear impact the anti-sub straps keep the buckle and lap belt in place and restrain the driver much better in the seat.

The disadvantage of this type of harness: the T-bar should be wide enough to properly separate the anti-sub straps but is then likely to stick into the upper thighs. To increase the comfort, the buckle is often not worn as low as it should for best lap belt positioning.

The solution: the revolutionary SCHROTH Hybrid™ Restraint.

The crotch straps are not routed through D-rings or attached to a T-Bar but are held directly by the specially developed lap belt latches.Thanks to the patented SCHROTH RFR™ rotary buckle the load tranfer from the shoulder belts through the buckle into the anti-sub straps and vice versa in case of a rear impact is achieved. This direct load transfer is important for optimal restraining performance.

Flexi Belt 2" Lap Belts

Flexi-Belt™ - one harness, many variations!

Length adjusters in lap belts come as 'pull-ups' or 'pull-downs'. In addition they often have to be positioned differently to achieve optimal operation. SCHROTH has developed the solution which covers your different needs with just one lap belt model: the 'Flexi-Belt™'.

The lap belt latches and brackets supplied with the harness can be assembled to the lap belt with a two-bar sliding bracket allowing you to change the configuration. With this you decide on pull-up or pull-down versions and if applicable, different for the left and right lap belt portion. You may also vary the lengths to optimize the adjuster position depending on your car, your seat and seating position. Even exchanging mounting hardware is possible (e.g. a bolt-in bracket for a snap-on bracket). 'Flexi-Belt™' is only available with 50 mm (2") lap belts, SCHROTH '-II' models.

QuickFit Harness Technology

SCHROTH QuickFit and QuickFit Pro harnesses integrate into the existing vehicle safety system. They build on the fantastic success of the SCHROTH Rallye series belts relying on the asm Technology to keep the occupant from submarining under the lap belt as well as reduce head and chest deceleration forces. The difference is in the details as it often is.

These harnesses utilize the available factory female receptacles for attachment points. This is what makes these harnesses so special - they integrate into the airbag system. Many of todays vehicles come with two stage airbag systems that will deploy at different rates depending on whether or not the computer detects that the occupant is buckled in. In a standard 4 point system, there is nothing plugged into the female receptacle, so the computer does not know you are restrained.

In addition, by plugging into the female receptacle, many vehicles (BMW and Mini for example) have a pyrotechnic pre-tensioner built into the receptacle that will automatically tighten the lap belt 2" in an impact. This alone is worth the increase in price over a standard Rallye belt.

Couple the safety benefits with the fact that you can completely remove the harness from the vehicle in less than 10 seconds, you have the best of both worlds: something safe and convenient.

SCHROTH QuickFit restraints are the pinnacle of technology for Street Legal restraints.


SFI 16.6 Homologation

SFI 16.6 is the latest seat belt standard that went into effect in 2015. For the 2016 racing season, SFI 16.6 specification belts will be mandatory for NASCAR Sprint Cup and Xfinity series with the NASCAR Truck series mandating SFI 16.6 belts for the 2017 season. The new SFI 16.6 specification adds additional safety standards to the already very stringent SFI 16.5 standards. The biggest change required in SFI 16.6 versus SFI 16.5 is the addition of a mandatory Negative G belt, making all belts either 7 or 9 point configurations. The Negative G belt is a center mounted sub-strap that acts to hold the camlock and lap belts in position on the pelvis bones during a roll over or negative G incident. The Negative G belt is mounted following the plane of the driver's chest straight to either the seat itself or the floor depending on your seat. By adding the Negative G in addition to the already required anti-submarine belts, an SFI 16.6 belt ensures the driver has optimal seat belt geometry in both a frontal accident and a roll over accident.

In addition to the required Negative G belt, SFI 16.6 adds an additional level of tensile strength testing of all individual components of a harness as well as the testing the mounting hardware, latching hardware and adjuster hardware for tensile strength. The tensile test requires that an individual belt component be able to withstand a test load without failure or slippage. The amount of load applied is determined by the body location and type of individual belt but all components must be capable of sustaining the load for 5 seconds, twice without failure. A single shoulder belt and its mounting hardware is tested to 3,500 lbs. of load, a double shoulder belt requires that the 3" body belt withstand 3,500 lbs. of load and the 2" over (HNR) belt withstand 2,500 lbs. Lap belts and mounting hardware must be able to hold 3,000 lbs. For single sub-straps such as those found in the Hybrid and Formula style belts, each sub-strap is loaded to 3,000 lbs. while for a T-bar style sub-strap the required load is 4,500 lbs with both sub-straps being tested at the same time. The Negative G belt is tested to 4,000 lbs. by itself whether it is standalone or part of a T-bar setup.

SCHROTH Racing worked tirelessly in the beginning of 2015 to ensure all of their style of belts passed SFI 16.6 in order to provide our customers with as many options as possible when required to run SFI 16.6. SCHROTH Racing has 2" and 3" lap belt configurations approved for SFI 16.6 in Profi, Hybrid and Formula style belts. Numerous different mounting brackets and hardware has been approved for SFI 16.6 to be used for shoulders, laps and sub-straps. SCHROTH Racing continues to offer custom sewn harnesses for professional drivers that want the utmost in comfort, weight savings and safety. Please contact HMS Motorsport directly for custom sewn options and configurations.

SFI and FIA Seat belt standards and expiration dates

There is a lot of confusion and misconception regarding racing safety seat standards and expiration dates. This technical bulletin will help clarify the different seat belt standards as well as the expiration dates for these different standards. Seat belt manufacturers produce belts that meet either the FIA homologation standards or the SFI standards for seat belts. The FIA is an organization that is based in France and provides rules and regulations for most international forms of racing including F1, World Rally and World Touring Car Championship. SFI is a USA based non-profit organization that issues and administers standards for racing equipment including safety equipment. The SFI foundation safety standards are the predominant safety standard used by most circle track racing organizations in the US including NASCAR, ARCA, USAC, World of Outlaws, and NHRA.

FIA BELTS

Sanctioning organizations can specify FIA standards without a fee to the FIA. Should a legal matter arise with a component meeting an FIA standard, the organization could use their complete compliance with the standard as a defense. FIA will not enjoin in the defense.

The FIA seat belt homologation, FIA standard 8853/98, requires that each element of a belt has an FIA tag with the year of expiration either punched or printed on the tag. The FIA standard is five years starting on January 1 of the year following the year of manufacture. For example, a 6-point seat belt purchased in 2015 will have a FIA tag on all 6 points of that belt stating that the belt is not valid after 2020. This means that a belt purchased in January 2015 would actually be usable for a full six (6) years. The FIA homologation standards require an individual belt to be replaced if the FIA homologation tag does not have a current date or is missing from the belt, the FIA does not require all tags to match in expiration date but they do need to be valid with a readable tag.

FIA homologated belts are typically used in sedan style race cars or open wheel formula cars that are well maintained and see very little exposure to harsh elements such as water, dirt, and mud. This standard is for a 5 or 6 point belts (5point belts will be disallowed by the FIA starting in 2018). The FIA homologation requires seat belts to pass certain breaking loads, elongation rates, abrasion resistance, and corrosion resistance as well as pass a dynamic crash sled test. Nearly all FIA seat belts use polyester webbing instead of nylon webbing. Polyester webbing has a much higher UV resistance than nylon as well as more resistance to water, oil and other contaminants. Polyester webbing is also superior to Nylon webbing in controlling elongation rates with less stretch and 'rubber band effect'. Nylon webbing has a standard elongation of 25% where polyester webbing can be manufactured with specific elongations ranging from 6% to 16% depending on the application requirement. Due to the predominant use of Polyester webbing as well as the typical application for an FIA belt, the FIA homologates the safety of its belts for 5 years plus the year of production. FIA testing and approval procedures are more costly - therefore FIA belts are typically more expensive than SFI belts. Over the useful life of a harness system, the price of an FIA belt, with up to six years validity compared to multiple sets of SFI belts may end up at a break-even or less expensive than the SFI belts over the same period of time. FIA does not permit re-webbing on their seat belts.

SFI BELTS

Any racing sanctioning organization is welcome to join SFI and to then specify SFI standards in their rule book. There is a very reasonable annual participation fee. The benefit of this is that SFI will join in and support in the defense of the sanctioning organization should there be a legal claim against the organization related to any component with SFI certification in their rule book. The organization must demonstrate that they are enforcing their rules according to the relevant SFI specification.

There are currently 4 different SFI standards for seat belts, these are SFI 16.1, 16.2, 16.5 and 16.6. SFI standard belts are required to pass multiple tests including elongation, webbing breaking strength and body block testing. The 16.5 and 16.6 standards add micro-slip, abrasion resistance tests, and 16.6 further adds individual component tensile tests.

  • SFI 16.1 applies a load over the body block of 5,750lbs each on the laps and shoulders and over the complete 5 or 6 point assembly. Webbing test (breaking load) must meet 6,300lbs for laps and shoulders and 1,500lbs for sub straps. SFI labels on left shoulder belt, left lap belt, and sub strap.
  • SFI 16.2 (junior-child belt) applies a load over the body block of 3,300lbs each on the laps and shoulders and over the complete 5 or 6 point assembly. Independent webbing tests (breaking loads) must meet 4,500lbs for laps and shoulders and 1,500lbs for sub straps. SFI label on left shoulder belt, left lap belt, and sub strap.
  • SFI 16.5 applies a load over the body block of 11,000lbs over the complete 5 or 6 point assembly. Webbing test (breaking load) must meet 7,000lbs for laps, shoulders and sub straps. Additional tests include a Roller Adjuster Micro-Slip Test, and Webbing Abrasion Test. SFI labels on each shoulder belt, each lap belt, and sub strap. Re-webbing not permitted. Mandated by NASCAR Truck Series, NHRA Top Fuel and Funny Car.
  • SFI 16.6 includes all 16.5 requirements with additional individual tensile testing of each sub assembly with loads ranging from 2,500 to 4,500lbs. Only polyester webbing is permitted. Requires a 7 or 9-point belt (additional Negative-G sub strap). SFI labels sewn on each shoulder belt, each lap belt, and sub strap. Re-webbing not permitted. Mandated by NASCAR Sprint Cup and Xfinity series for 2016.

Seat belts manufactured to any of the SFI standards, are valid for two (2) YEARS from the date of manufacture. An SFI spec belt will have a tag(s) where the month and year of manufacture are clearly punched. SFI certifies that this belt will meet the safety standards for only 2 years from this date. Once the belt has passed its 2 year life expectancy, the SFI no longer certifies that this belt meets its safety standards and the racing sanctioning body should no longer allow this belt on track. SFI permits 16.1 and 16.2 belts to be re-webbed but not the more stringent 16.5 and 16.6 standards.

The primary reason for the difference in life expectancy between SFI and FIA belts result mainly from the material (Nylon vs. Polyester) and from the typical usage of the belt by the racer. SFI belts are most common in drag racing, and circle track racing (often on dirt). These belts often see heavy wear and tear in the course of an event and are subjected to the elements such as mud, water, and oil. The entire car (including the belts) are often hosed off after an event (including the belts) and left exposed to the sun. Under such conditions, a belt may no longer be safe after less than a year of use and should be replaced, at the better discretion of the racer, to ensure maximum safety. SFI has conducted extensive testing on seat belt webbing degradation when exposed to UV light, water, and other elements and has determined that a seat belt cannot be used safely for more than 2 years in such conditions. Most SFI 16.1 seat belt uses Nylon webbing which loses as much as 75% of its original tensile strength after 30 months of UV exposure. This is the main reason SFI mandates belts be replaced every 2 years.

SUMMARY

The FIA and SFI create the standards, certify that manufacturers are meeting the standards and defend the standards if their validity is called into question. If a sanctioning body such as SVRA quotes any SFI or FIA standard in their rule book and fully complies with the standard, then the FIA standard can be used as a solid defense. SFI will go so far as to assist in the defense in the event of an accident and litigation. However, if a sanction body does not fully enforce the specified standard, such as allowing SFI belts to be used for more than 2 years, then the sanctioning body is in direct violation of the SFI standard and SFI will no longer support the sanctioning body in the event of litigation. Further it is likely that a good lawyer could claim gross negligence for not enforcing a stated standard.

The metal hardware in a race seat undergoes numerous cycles of loading/unloading during its life time and it is impossible to certify that the hardware is still valid without X-raying each component for cracks. For this reason, it is highly recommended that the entire seat belt assembly is replaced at the end of its life and the hardware not be used again.

The responsibility of the safety of an expired seat belt shifts from the SFI (or FIA) to the sanctioning body and the tech inspector that approved the expired belt to go on track. This opens up the possibility for litigation against both the sanctioning body and the tech inspector with no coverage from the SFI Foundation. This is why it is very important for a sanctioning body such as SVRA, SCCA, NASA, etc to require either SFI or FIA safety standards and to enforce all the rules of those standards including the expiration dates of the belts.

HMS Motorsport is the exclusive North American importer for Schroth Racing harnesses as well as Stilo helmets. HMS Motorsport has worked and continues to work closely with sanctioning bodies such as SVRA, SCCA and NASCAR to improve their safety standards and ensure all drivers are as safe as possible. HMS Motorsport and Schroth work closely with the safety foundations to improve their standards and stay current with the latest specifications.

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