Fixed Back Seats and Roll Bars
Fixed Back Seats and Roll Bars
In an effort to actually bring my car down to the correct weight for SM I'm thinking of going with a set of fixed back seats. Only problem is, I do several HPDE/PDX events a year. Several friends of mine have commented that if I wanted to do both I should get a roll bar to prevent any possible damage from a roll over at the track. My thoughts on that were "why save weight with the fixed backs if I'm going to gain it back by adding a roll bar.". Does anyone have any thoughts on it here?
The car is used mostly for autox and DD on dry days with some long distance travel to events. I also use the rear seat for packing equipment for the events so a roll bar in the back would hinder that somewhat.
The car is used mostly for autox and DD on dry days with some long distance travel to events. I also use the rear seat for packing equipment for the events so a roll bar in the back would hinder that somewhat.
Depending in the seat you choose, you will need a roll bar to properly install a seat back brace. The added weight of roll bar gives you extra safety and also adds more chassis rigidity. Your friends are right, do some searches of pics of rolled cars and you will see why they recommend the roll bar.
Here is a cut and paste of a larger article I drafted that talk about the seats
In short, there are two types of seats: fixed back (aka buckets) or reclining. Almost all street cars are supplied with a reclining seat. The stock reclining seat backs have been known to break during some impacts (especially the ones where a car backs into a wall). If the seat brakes, you body is projected backwards towards the back of the car, head first. You may have a roll bar and if that is the case, imagine the seat braking, and then hitting the harness bar. Probably would feel like someone hitting you square in the back with a baseball bat (I say probably because fortunately I managed to avoid experiencing either case).
Because of the above and the harness requirements, you should invest in a proper racing seat. The majority are of the bucket type and made from different materials. There are also some reclining seats that are built to high specifications but there are none that are FIA homologized. The highest certification I came across are ones meeting the German TUV standards. Not all buckets racing seats are FIA homologized either. Any seat that is not FIA 8855-1999 (or higher) homologated must be used with a properly matched and installed seat back brace from preventing the seat back from breaking upon impact. In fact, NASA requires that an FIA approved seat older than 5 years old, may require the presence of a seat back brace anyway.
Shell-type seats tend to be lighter than steel tube seats, and spread the force of the impact over the larger surface area. Shell-type seats can be made from aluminum or sandwiched composites like fiberglass, Kevlar, carbon fiber or a carbon fiber/Kevlar mix. Aluminum seats offer high strength, it's fairly lightweight, and it has the ability to absorb energy through deformation without failure. Fiberglass has the cheapest material cost of any of the composites, and is thus used in many seats. Because fiberglass is not as strong as carbon fiber or Kevlar, more of it needs to be used, meaning the resulting seat is often heavier. Kevlar is extremely strong, but not extremely stiff, and is the best of the composites at absorbing energy. Carbon fiber is very light, very stiff, and strong, but it's expensive and brittle compared to Kevlar. Carbon/Kevlar fabric can blend the strength of the carbon fiber with the energy absorption properties of the Kevlar to yield ideal protection. Seat design, fabric layup, resin and operator skill all have tremendous bearing on the quality of a finished composite seat, of any material.
When you think about choosing seats, you probably think of fit and comfort. Although considered trivial, choose the tightest seat you will feel comfortable in and getting in and out of. Remember, this is still supposed to be your daily driver car, getting in and out can become a real drag with the wrong seat. Also, daily driving can become literally a nuisance with the seats that have the head wings on them. You will not be able to see anything to the side or even check your blind spot. Note that when a car is built, the factory matches the seats to their other restraint systems. Replacing that seat may offset that balance and your daily driving may be compromised in terms of safety.
Installation is another huge component and cost of the seat project. You will require brackets, optionally sliders and side mounts for most bucket seats. Thoroughly research your brackets and sliders. Some may be SFI certified. I have seen some less costly brackets that appear to have flimsy look and feel to them. The first image you should visualize is this: You are in a seat that is attached to a sled using the seat brackets you are considering. The sled starts to free-fall down the rail attached to the side of a 12 story building when it suddenly stops before the ground floor. Will that hardware hold the seat and you in place? If your gut feeling on this is NO, do further research on that manufacturer to convince you otherwise or move on to a different product. As with the harness installations, proper grade hardware is required.
You may also run into potential problems mounting the stock seatbelts with your race seats and race seat mounting kits. Sometimes custom modification to seat bases is required. If you choose that route, make sure you have this done by a race shop specializing in building roll bars and other safety gear and avoid Joe at your local Midas shop for this. Experience and knowledge of the forces involved is the key to making your car safe here.
You would think this is it, but there is more. Many newer cars have sensors build into the seats giving feedback to the stock seatbelts, the air bag systems and other safety related components. Various error codes may thrown by your cars computers. You will have to investigate what is affected by these codes on your car to make sure you are not putting yourself in more danger. There exist kits or procedures to "fool" the sensors that everything is just fine but understand what these sensors and systems do in an accident, and if it is appropriate to fool them. There is usually more than meets the eye with these electronics and gadgets (especially on newer cars) so spend a significant amount of time researching this.
Here is a cut and paste of a larger article I drafted that talk about the seats
In short, there are two types of seats: fixed back (aka buckets) or reclining. Almost all street cars are supplied with a reclining seat. The stock reclining seat backs have been known to break during some impacts (especially the ones where a car backs into a wall). If the seat brakes, you body is projected backwards towards the back of the car, head first. You may have a roll bar and if that is the case, imagine the seat braking, and then hitting the harness bar. Probably would feel like someone hitting you square in the back with a baseball bat (I say probably because fortunately I managed to avoid experiencing either case).
Because of the above and the harness requirements, you should invest in a proper racing seat. The majority are of the bucket type and made from different materials. There are also some reclining seats that are built to high specifications but there are none that are FIA homologized. The highest certification I came across are ones meeting the German TUV standards. Not all buckets racing seats are FIA homologized either. Any seat that is not FIA 8855-1999 (or higher) homologated must be used with a properly matched and installed seat back brace from preventing the seat back from breaking upon impact. In fact, NASA requires that an FIA approved seat older than 5 years old, may require the presence of a seat back brace anyway.
Shell-type seats tend to be lighter than steel tube seats, and spread the force of the impact over the larger surface area. Shell-type seats can be made from aluminum or sandwiched composites like fiberglass, Kevlar, carbon fiber or a carbon fiber/Kevlar mix. Aluminum seats offer high strength, it's fairly lightweight, and it has the ability to absorb energy through deformation without failure. Fiberglass has the cheapest material cost of any of the composites, and is thus used in many seats. Because fiberglass is not as strong as carbon fiber or Kevlar, more of it needs to be used, meaning the resulting seat is often heavier. Kevlar is extremely strong, but not extremely stiff, and is the best of the composites at absorbing energy. Carbon fiber is very light, very stiff, and strong, but it's expensive and brittle compared to Kevlar. Carbon/Kevlar fabric can blend the strength of the carbon fiber with the energy absorption properties of the Kevlar to yield ideal protection. Seat design, fabric layup, resin and operator skill all have tremendous bearing on the quality of a finished composite seat, of any material.
When you think about choosing seats, you probably think of fit and comfort. Although considered trivial, choose the tightest seat you will feel comfortable in and getting in and out of. Remember, this is still supposed to be your daily driver car, getting in and out can become a real drag with the wrong seat. Also, daily driving can become literally a nuisance with the seats that have the head wings on them. You will not be able to see anything to the side or even check your blind spot. Note that when a car is built, the factory matches the seats to their other restraint systems. Replacing that seat may offset that balance and your daily driving may be compromised in terms of safety.
Installation is another huge component and cost of the seat project. You will require brackets, optionally sliders and side mounts for most bucket seats. Thoroughly research your brackets and sliders. Some may be SFI certified. I have seen some less costly brackets that appear to have flimsy look and feel to them. The first image you should visualize is this: You are in a seat that is attached to a sled using the seat brackets you are considering. The sled starts to free-fall down the rail attached to the side of a 12 story building when it suddenly stops before the ground floor. Will that hardware hold the seat and you in place? If your gut feeling on this is NO, do further research on that manufacturer to convince you otherwise or move on to a different product. As with the harness installations, proper grade hardware is required.
You may also run into potential problems mounting the stock seatbelts with your race seats and race seat mounting kits. Sometimes custom modification to seat bases is required. If you choose that route, make sure you have this done by a race shop specializing in building roll bars and other safety gear and avoid Joe at your local Midas shop for this. Experience and knowledge of the forces involved is the key to making your car safe here.
You would think this is it, but there is more. Many newer cars have sensors build into the seats giving feedback to the stock seatbelts, the air bag systems and other safety related components. Various error codes may thrown by your cars computers. You will have to investigate what is affected by these codes on your car to make sure you are not putting yourself in more danger. There exist kits or procedures to "fool" the sensors that everything is just fine but understand what these sensors and systems do in an accident, and if it is appropriate to fool them. There is usually more than meets the eye with these electronics and gadgets (especially on newer cars) so spend a significant amount of time researching this.
... and if you will consider a roll bar, here is cut and paste on the bar section:
Fortunately there is not much to roll bars. Pretty obvious what they do. There are weld-in bars and bolt in-bars. The weld-in is considered safer as they are permanent and have a lesser chance of ripping off. Bolt ins are more desirable by some that do not have a dedicated track car since it can be removed at a later time and the car returned back to original interior. Remember to use vendor supplied backing plates and properly graded hardware (nuts and bolts).
If you have a roll bar installed and back seats, your car just became 2 seater. You should never drive with people in the back when a roll bar (or harness bar for that matter) is installed. Exposed solid metal bars (even when padded) are not too friendly to people's bodies and heads. Even in a slow impact, the body damage is too great to risk it. For this reason, you will almost never see people drive cars with full cages on the road because it is too risky to the drivers head without a helmet and being properly strapped in.
What about roll bar padding – will that not protect if I add it? The answer is sort-of. The soft foam-like stuff that feels like it will, is only good for protecting someone from banging on the metal directly when getting in or out of a car. Think about it, you can compress the foam with your finger with not much effort, in a 30 to 0mph impact into a concrete barrier, as much as 80G can be generated on your body. Do you think that piece of foam that you can pinch between your fingers is going to be of any help? The other type of roll bar padding is the dense stuff, which you can't pinch with fingers. Most think that it is of no value as it is not soft. On the contrary, this material is what deforms and absorbs some of the impact. But given that it is so hard, you are still taking a significant risk without a helmet and without being properly strapped in.
Some roll bar padding is SFI/FIA certified and there are fire resistant and non-fire resistant versions. Make sure to investigate the detailed specs between the cheaper and more expensive stuff – there is a reason some padding is more than others. You just invested over a grand on a helmet, harness and a roll bar. Are you really going to go cheap on some roll bar padding to save twenty bucks? It just makes no sense to do that when the whole picture is taken into account.
Several debates can be found where people argue that hitting a padded roll bar is no different than hitting the plastic interior of any modern car. You can even find the references that some certified padding passes the NHTSA (National Highway Traffic Safety Administration) standards... but, the bar is much closer to the passengers heads and protrudes inside creating obstacles from an otherwise virtually smooth interior. Research and use your brain to determine if you are willing to take that risk for your passenger or as a passenger before getting in.
If building or buying a pre-made roll bar, make sure it satisfies the SCCA (Sports Car Club of America) and NASA (National Auto Sport Association) required specifications. This is so it meets some minimal safety requirements. In the future it can be easier to build on to the bar to make a full cage or have a greater chance selling it to someone else. One of the primary components is the tube diameter/thickness for the weight of your car. The type of material for the roll bar also matters. Proper design, welding and technique are also key items that make or break a roll bar. Make sure you research the roll bar builder before buying or ordering a roll bar. One of the most popular bolt-in roll bar manufacturers in the US is Autopower. They most likely already have a bar ready to be put in for your vehicle.
By all costs avoid the "show cages". These are usually made from thinner tubing, have all sorts of fancy bends to work around the car's interior and are basically not that effective from a protection point of view. None of these bars would meet the minimal safety standards of the major racing organizations.
Harness bars are used by some for the proper installation of the shoulder harnesses. But that goes against the general rule of not using harnesses without a roll bar so I personally find them a non-required product. If you have a proper roll bar, you will have the harness bar on the roll bar for proper installation.
Fortunately there is not much to roll bars. Pretty obvious what they do. There are weld-in bars and bolt in-bars. The weld-in is considered safer as they are permanent and have a lesser chance of ripping off. Bolt ins are more desirable by some that do not have a dedicated track car since it can be removed at a later time and the car returned back to original interior. Remember to use vendor supplied backing plates and properly graded hardware (nuts and bolts).
If you have a roll bar installed and back seats, your car just became 2 seater. You should never drive with people in the back when a roll bar (or harness bar for that matter) is installed. Exposed solid metal bars (even when padded) are not too friendly to people's bodies and heads. Even in a slow impact, the body damage is too great to risk it. For this reason, you will almost never see people drive cars with full cages on the road because it is too risky to the drivers head without a helmet and being properly strapped in.
What about roll bar padding – will that not protect if I add it? The answer is sort-of. The soft foam-like stuff that feels like it will, is only good for protecting someone from banging on the metal directly when getting in or out of a car. Think about it, you can compress the foam with your finger with not much effort, in a 30 to 0mph impact into a concrete barrier, as much as 80G can be generated on your body. Do you think that piece of foam that you can pinch between your fingers is going to be of any help? The other type of roll bar padding is the dense stuff, which you can't pinch with fingers. Most think that it is of no value as it is not soft. On the contrary, this material is what deforms and absorbs some of the impact. But given that it is so hard, you are still taking a significant risk without a helmet and without being properly strapped in.
Some roll bar padding is SFI/FIA certified and there are fire resistant and non-fire resistant versions. Make sure to investigate the detailed specs between the cheaper and more expensive stuff – there is a reason some padding is more than others. You just invested over a grand on a helmet, harness and a roll bar. Are you really going to go cheap on some roll bar padding to save twenty bucks? It just makes no sense to do that when the whole picture is taken into account.
Several debates can be found where people argue that hitting a padded roll bar is no different than hitting the plastic interior of any modern car. You can even find the references that some certified padding passes the NHTSA (National Highway Traffic Safety Administration) standards... but, the bar is much closer to the passengers heads and protrudes inside creating obstacles from an otherwise virtually smooth interior. Research and use your brain to determine if you are willing to take that risk for your passenger or as a passenger before getting in.
If building or buying a pre-made roll bar, make sure it satisfies the SCCA (Sports Car Club of America) and NASA (National Auto Sport Association) required specifications. This is so it meets some minimal safety requirements. In the future it can be easier to build on to the bar to make a full cage or have a greater chance selling it to someone else. One of the primary components is the tube diameter/thickness for the weight of your car. The type of material for the roll bar also matters. Proper design, welding and technique are also key items that make or break a roll bar. Make sure you research the roll bar builder before buying or ordering a roll bar. One of the most popular bolt-in roll bar manufacturers in the US is Autopower. They most likely already have a bar ready to be put in for your vehicle.
By all costs avoid the "show cages". These are usually made from thinner tubing, have all sorts of fancy bends to work around the car's interior and are basically not that effective from a protection point of view. None of these bars would meet the minimal safety standards of the major racing organizations.
Harness bars are used by some for the proper installation of the shoulder harnesses. But that goes against the general rule of not using harnesses without a roll bar so I personally find them a non-required product. If you have a proper roll bar, you will have the harness bar on the roll bar for proper installation.
you're going down divergent paths. Competitive autox build doesn't really mix with a track day build.
fwiw; I think my Autopower bolt-in rollbar is something like 60-70 lbs (guess). That's a lotta weight to gain even if you are losing say 30-40lbs with lighter seats.
Keep in mind you'll lose the ability to carry passengers in the back seat. You'll also find it VERY difficult to fit tires back there unless you modify the entry bar (I have) or remove the passenger seat and roll them in very carefully.
On the other hand, I personally have zero regrets having that extra weight in the car - I see it as safety for the 130+mph speeds I see regularly on the track.
Keep in mind you'll lose the ability to carry passengers in the back seat. You'll also find it VERY difficult to fit tires back there unless you modify the entry bar (I have) or remove the passenger seat and roll them in very carefully.
On the other hand, I personally have zero regrets having that extra weight in the car - I see it as safety for the 130+mph speeds I see regularly on the track.
fwiw; I think my Autopower bolt-in rollbar is something like 60-70 lbs (guess). That's a lotta weight to gain even if you are losing say 30-40lbs with lighter seats.
Keep in mind you'll lose the ability to carry passengers in the back seat. You'll also find it VERY difficult to fit tires back there unless you modify the entry bar (I have) or remove the passenger seat and roll them in very carefully.
On the other hand, I personally have zero regrets having that extra weight in the car - I see it as safety for the 130+mph speeds I see regularly on the track.
Keep in mind you'll lose the ability to carry passengers in the back seat. You'll also find it VERY difficult to fit tires back there unless you modify the entry bar (I have) or remove the passenger seat and roll them in very carefully.
On the other hand, I personally have zero regrets having that extra weight in the car - I see it as safety for the 130+mph speeds I see regularly on the track.
This is true as well, and I've thought about it several times. The days up at Mid-Ohio I've seen upwards of 140mph on the back straight. That was also when I had Hawk HPS pads trying to slow the car down to 50 mph for turn 3
I may end up looking into a bolt in cage that can be removed for regular street driving, but added back in for track days. The other thought was keep a regular drivers seat around for track days and bolt it in for the weekend.
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