Understanding The Aims And Concerns Of A Racing Seat

I occasionally hear people moaning about how expensive safety equipment is, while simultaneously talking about the bargain they found on a new lightweight exhaust, a set of new shocks, or something as trivial as a pair of late model tail lights. Call me bland, but I can’t understand how someone can have a difficult time justifying a relatively meager expense where their life is concerned, yet have no problem splurging on those shiny new headers. At the end of the day, the most important thing is getting home in one piece, preferably with a car that’s in one piece as well.

For the stubborn friend with more fashion sense than common sense, a quick browse of YouTube should be enough to convince them of the value of top-notch safety equipment. Perhaps one of the more violent but ultimately harmless accidents seen in recent years — Tim Bell’s brake failure — might’ve ended more than his race had it not been for the right gear and a smidgen of luck.

Somehow, even after his heavyset 370Z Continental Tire car hit the wall at 136 mph, Bell could walk away — admittedly shaken — yet still lucid. It’s a testament to the sturdiness of modern Continental Tire cars, but also of the incredible safety of the head containment-style Racetech seat which kept his neck from snapping during that horrendous hit.

It’s this sort of lateral impact for which the head-containment seat was designed. Those long wrap-around pieces limit the range of lateral movement a head can experience under rapid deceleration. A head-containment seat adds lateral support not found with a standard race seat, both in the neck and shoulder regions.

After consulting several authorities on the nature of the modern racing seat, we’ve discovered exactly what helps keep a driver safely enveloped in the seat, how body shape dictates seat design, and what developments to the racing seat we’ve seen over the last several decades.

Door bars, a window net, and a proper seat make all the difference. Photo credit: Tim McAmis

To get a better sense of how the seat and the body interact, we consulted the wise and experienced Kelli Willmore, Senior Business Unit Leader for Motorsport Safety at Momo. “Drivers should select a seat that fits their build comfortably and also offers adequate hip containment, side support, and lateral head containment,” she says. However, the driver’s fitment inside the seat is determined as much by the contours of the seat as it is by the restraint system. For this reason, ensuring the harnesses and belts are cinched properly is of utmost importance.

MOMO’s Daytona Evo seat provides square shoulder support for great torso containment. Photo credit: MOMO

Belting in Properly

The opening in the seatback, also known as the passthrough, needs to be roughly at shoulder height so the shoulder belt is at precisely the right angle. Not getting this right could be very dangerous. “The passthrough should allow the shoulder belts to mount horizontal to the driver’s shoulder line, with optimum installation at -10 degrees below horizontal,” notes Willmore. “If the driver is too tall and the shoulder belt is angled at more than twenty degrees from the top of the passthrough to the shoulder, they run the risk of spinal compression or collar bone injury. On the other hand, if the passthrough is too high above the driver’s shoulder, the shoulder belt won’t keep the driver secured safely in the event of a rollover.”

“Many drivers make the mistake of ‘over-cinching’ their shoulder belts however, which can potentially create more issues — mainly with loading and spinal compression,” Willmore continues. “The shoulder belts are only meant to keep a racer held back into their seat, and should not be over-tightened to the point of compressing the spine. Instead, a racer should tighten the lap belt as much as possible, since this is the belt that should be doing all the work in the event of a crash or roll-over.” We’ll address this point later in the article.

“The seat should be mounted to allow for proper restraint angle installation,” Willmore adds, “It is also important to ensure the seat installation provides a clear path for the webbing to pass through the belt guides without becoming hung up on other chassis components or sharp edges. The seat should also have a restraint pass through for the negative G belt, also known as the anti-sub belt.”

Male drivers are familiar with the odd mixture of reassurance and discomfort the anti-sub belt brings. While the anti-sub belt tends to compress the nether region slightly, which can be distracting (and worrying to a man interested in having children), it does significantly reduce the chances of submarining: where a driver slips under the belts into the footwell.

Kinesiology of a Human Body During an Incident

The Iliac Crest—the curved ridge at the top of the pelvic bone—forms the most prominent and largest bone in the pelvis. This area of the body is generally most capable of withstanding force, which is why it is important for the lap belts to fit as low, as tightly, and as comfortably into the depression below the Iliac Crest as possible. The anti-sub belt ensures these belts are properly positioned for the ideal fitment.

 

Here, the ideal seating position within a 991 GT3 Cup’s Recaro shell as shown. Photo credit: Recaro Automotive Seating

“When impact loads to the pelvis are contained faster, the impact loads spreading into the chest are reduced. Chest (and neck) loads from an impact do not begin until the pelvis has stopped moving,” warns Willmore. “The more movement in the pelvis, the greater the force is that travels up to the chest and neck, thereby increasing the potential risk for injury.”

Brian Oleshak, Vice President of North American Sales at Racetech, elaborates on the way the body moves in the event of an accident, and how the seats aim to contain the occupant:”The head containment seat reduces the chances of a side impact against a rollbar tube, and keeps the body properly aligned in the event of a rollover or side impact. It also reduces strain on the neck and shoulders.”

In the event of a crash, the traditional racing seat can leave the driver exposed in some respects. “Without greater shoulder support, the torso typically tries to slip out over the shoulder support and the harness,” notes Oleshak. This movement increases the chances of bruising a kidney or cracking a rib.

Racetech aims to maximize protection for the American male body — which is generally a bit wider — in four areas. These are the thigh/femur, hips, shoulder/upper torso, and the head/neck. “If all of these areas are protected well, and they’re kept in healthy relation to one another, the driver can theoretically walk away from a 100-G impact,” Oleshak notes. “The intention with our seats is to keep bodily movement to a minimum, and we do much of this with the perfect contours as well as energy absorbent foam,” Oleshak adds.

If the head, neck, shoulders, and torso are kept in alignment with one another, the driver can handle a massive impact. Photo credit: Racetech

Shaping a Seat for the Circumstances

Racetech was one of the pioneers of the head containment seat. It stands to reason then that Racetech was contacted by Dodge to provide a safer seat to fit in the then-new Viper Competition Coupe — a tube-framed car, which would go on to race in Pirelli World Challenge and Grand-Am. Their concerns revolved around avoiding a lawsuit primarily, but its success has made it ubiquitous in the world of production-based racing cars. Because these cars appeal to a wide variety of users, it must be constructed in a way that accommodates everyone without sacrificing anything in terms of safety.

Despite the size, the Racetech seat nestles neatly inside the Viper R’s cramped cabin. Photo credit: McCann Racing

Body dimensions of racing drivers differ depending on the category, and so Recaro designs its seats to suit the context in which they’re used. “In professional motorsport, the drivers are slim and need to have the best possible lateral support. Drivers in semi-professional racing series are looking for more comfort. Recaro offers racing shells in different sizes: the optional XL version is both wider and higher. Furthermore, Recaro also offers replaceable pad kits in order to fit the different body shapes,” says Ulli Andree, Director of Global Communications at Recaro Automotive Seating and semi-professional racing driver. In 2012, Andree won the German Endurance Championship using a Recaro shell.

In professional racing, drivers are slimmer and need the most lateral support possible. Photo credit: Swedish Touring Car Championship

“Furthermore, the requirements of individual racing teams and drivers are a decisive factor. Depending on their racing environment, they lay stress on the factors such as safety, comfort, or weight,” Andree adds. Additionally, the category and style of car or competition dictate the aims of the seat.

Seat Mounting/Position

“A rally driver sits in an upright position, he needs a rigid side mount, as there are no changes of driver during the race,” Andree says. “Yet a GT pilot drives in a half-lying position. In long-distance races with driver changes, he needs to adjust the position of the shell for optimal ergonomics and the highest level of safety.”

Additionally, the introduction of the HANS system, which influences the seating position of the driver, has dictated the shape of the racing seat. “Therefore, the shell needs to be designed in a way to optimally support the HANS system and to make sure that the driver has maximum control over the car. Only if all of the safety components — racing shell, HANS system, and seat belt system — are attuned to one another, then maximum safety can be guaranteed,” adds Andree.

Timo Berhnard sitting upright in his private rally car. Photo credit: Recaro Automotive Seating

This even pertains to the mounting system, as Andree notes: “For races that do not require a driver change, a fixed adapter ensures the shell is optimally mounted in the vehicle. A flexible adapter makes it possible to adjust the length position of the shell. This is ideal for long-distance races with driver changes.”

The mounting of a seat is a critical determinant of resilience in a crash. As mentioned in Racetech’s video, by mounting a racing seat to the floor as well as to the rollcage (also known as back-mounting), they improve performance and safety in several ways. The driver moves far less in a crash, they enjoy greater feel as the cage transmits more information through the seat, and engineers have been noting they’re seeing greater structural rigidity in the car, since the seat is such a strong part of the car.

Changes in Recent Years

“With the introduction of higher safety regulations, new and safer lightweight materials are needed due to the fact that racing cars need to become safer, but not heavier,” adds Andree. “Under the new FIA norm 8862-2009, racing shells need to withstand forces that are 4.6-times greater compared to the previous norm. At the same time the weight of the shell is not to be increased by the same factor.”

In testing for the new FIA standard, the P1300GT was subjected to forces between 3.3 metric tons and 6.1 metric tons. Photo credit: Recaro Automotive Seating

Willmore, having been in the business for some time, told us the most notable changes she’s seen made to the racing seat in the last twenty years:

  • Better composites
  • Technology advances in high-resiliency foam, allowing for improved energy attenuating properties (the key to managing a crash is to reduce the amount of energy over time and to attenuate it, or disperse it, as much as possible. The new HR foams on the market allow for better energy mitigation).
  • Advanced guidelines on proper seat mounting and positioning
  • Advanced guidelines on proper restraint mounting – properly mounted seats and restraints drastically reduce the potential for injury. Improperly mounted seats and restraints can cause injury.

Constructing the Perfect Racing Seat

Naturally, building a racing seat which can withstand severe impacts takes a strict and measured approach to construction. Throughout the build process, the seat is subjected to quality inspections and altered to the specific design of a particular model.

The materials used depend largely on the application. Racetech makes carbon/Kevlar seats for amateurs who don’t mind a mild weight increase in exchange for a better price. Professionals require the lightest available seats, so their seats are carbon throughout, and utilize different weaves for the utmost in strength in the lightest possible package.

An in-depth look into Racetech’s elaborate manufacturing process. 

At Momo, the manufacturing process for a carbon/Kevlar seat begins with the mold. Depending on whether the seat is a “hand” lay-up or produced in an autoclave, will determine the second step of the manufacturing process.

“Once the material is set, the seat shell is removed from the mold and trimmed using a jig/template or trimmed using a 5-axis CNC process,” Willmore provides. “During the trimming phase, the restraint passthroughs and other necessary hardware are added to the seats. After trimming, the seats are prepped for paint and/or clearcoat and then polished. Once the paint or clear coat is dry, multiple density foams are applied along with the fire retardant upholstery fabric. Quality control checks are in place during the various steps of the production process.”

Though the Profi SPG XL seat doesn’t provide head containment, it does offer greater ease of ingress/egress and accommodation for wider drivers. Photo credit: Recaro Automotive Seating

To cater to drivers of different heights and widths, Recaro Automotive Seating uses a building-block system, which consists of a Recaro racing shell and a fixed adapter or flexible substructure. “Each driver can put together his own ideal system, suited to his personal requirements and racing needs,” adds Andree. Additionally, Recaro offers racing shells for short- and long-distance races, for amateurs as well as for professionals. Thanks to its pad system, large and slim drivers alike can adjust the shell to conform to their body shape.

For the meager price of reduced peripheral vision, any sensible driver can enjoy all the added safety and peace of mind offered by a head-containment seat. A perfect fit, comfort, weight reduction, and added stability in the car are all offered by the current crop of high-end racing seats, which are a must for any serious driver — amateur or professional. There are many different options when it comes to racing seats, but do your homework and make sure you get one that fits correctly, is comfortable, and works with your harness system.

Article Sources

About the author

Tommy Parry

Tommy Parry has been racing and writing about racing cars for the past seven years. As an automotive enthusiast from a young age, he worked jobs revolving around cars throughout high school, and tried his hand on the race track on his 20th birthday. After winning his first outdoor kart race, Tommy began working as an apprentice mechanic to amateur racers in the Bay Area to sharpen his mechanical understanding. He has worked as a track day instructor and automotive writer since 2012, and continues to race karts, formula cars, sedans, and rally cars in the San Francisco region.
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