Racing Seat Prep Question

[mike_hinson]

I raced in the MORE race this weekend in Class 9 and had a bad experience on lap #2. Hit a big hole on the left rear and bottomed out the left rear side. My seat then bottomed out on the belly pan and compressed my lower back. That ended my race and today I am still in a lot of pain.

Seats in car are new PRP and this was only our third race on them. My son was riding with me and he did not get the jolt that I did. Is there something I should be doing to the seats when prepping, or should I change the seats to another brand?

I can't afford another injury like this one. The car hit so hard that the left rear rubber stop was smashed off. The previous two races we bottomed out the seats several times seat but nothing as severe as this time. Any suggestions would be appreciated.
Thanks,
Mike Hinson - 938

[Byrdman]

I would stick with either Beard or Mastercraft. Those "other" seats may not use the same webbing material and could probably be the reason why your seat bottomed out.
A stiffer material may seem harsh, but won't accellerate your body into a hard stop.

[Brandon_Charley]

From what I've read on here this is a potential problem for all suspension seats. This is why the TT guys use the Sparco seats.

[dislocated1]

How about slow down?

[mfs]

sounds like the car needs to be stiffer or diff shocks (bypass?) or air bumps, also. but your seat is moving way to much.
this scares me i have heard of guys hurting their backs with sup seats, and then runing sparkco seats. i have just got some prp seats too and after readind this (i have them here in my office) i stood in one and could make it allmost bottom on the floor.its only 1" of to start out. how much is yours moving? how much space to the floor when u are sitting in it? how about raising the seat up or lowing the floor board so u dont bottom the seat? and/or anding more webbing under the seat?
i would not run it again till u get it fixed its not woth geting hurt again.

[ChuckH]

Its a class 9 , no bypass or air bumps allowed, just buy a non suspension seat, im surprised their legal just because of this kind of thing happening, i doubt any other big racing body would ever allow them because they let you move to much in your seat and in a very dangerous way that can harm your spine.

People that have crashed know you want your seat belts as tight as you can get them, with the bottom of the seat moving no way can you ever really get your belts tight.

[mike_hinson]

I asked the same question on the MORE site. I was advised on that site that I need 3"-4" of clearance between the pan and the bottom of the seat. I only have about 2" of clearance right now. I may have to raise the seats up. How much clearance do most people have under their seats? Slowing down is not an option.
Thanks,
Mike Hinson

[billymanfroy]

Mike,

I didn't search, but there were some threads prolly a year or more ago about this very thing. We have noticed A LOT of buggies with this problem over the years. It's usually a matter of people needing to get 'em as low as possible to keep their heads below the roof. Small buggies like 9's seem to be the worst, especially if you're tall. PCI Scott mentioned that he has his (Mastercrafts or Beards, can't remember which he swears by) rebuilt every year so that the suspension material (string, basically) isn't all stretched out and worthless. Plueg... Flooo. Fearles won't touch a suspension seat, and swears by the Sparcos. There was talk then that the PRP's were cheaper for a reason, and the construction was one of them. I have no way to substantiate that and am not flaming them, just what I heard. If you can't lift the seats to at least 4" off the pan (Mines ~6"), can you at least lower the pan under your rump? Obviously, if that drags on the ground, you're going to be in a LOT worse trouble, so be careful. Tilting them back a little helps TONS, but many people don't have he room for that, either. Hope this helps, if not, try to search for the old thread. Lot of good info in it.

Billy

[mfs]

just buy a non suspension seat, im surprised their legal just because of this kind of thing happening, i doubt any other big racing body would ever allow them because they let you move to much in your seat and in a very dangerous way that can harm your spine.

People that have crashed know you want your seat belts as tight as you can get them, with the bottom of the seat moving no way can you ever really get your belts tight.

the seat is azorbing energy so if u have have a seat thats soild wouldnt that compess your back more? ya it would hold your back stright . it would be like like sitting on the floor of the car all the time. or like putting your back in a press and compressing it. right? i just dont understand so school me. i have mounted alot of the sparkco seats in drift cars, but it seems to stiff for off road, my freind ron rode in rg tt and he said they where to stiff.

[class51600]

I alway rode on stiff seats and never had a problem, I think is has to do with the 5 point keeping you tight down.

[Ramsey_ElWardani]

the seat is azorbing energy Isn't that spelled ASSorbing?

[ChuckH]

mfs
The car bottomed out and was coming back up while his body was still coming down, thus maganinfing the impact on him, a solid seat would have had less force.

There used to be a old TV ad about wearing seat belts that showed the efect, they taped a egg to the bottom of a small box ( the box was just a little bigger than the egg) then slamed it onto a table, the egg didnt break, then they did it with a un taped egg and it broke.

Sure a suspension seat is more comfortable, so are shorts and a Tshirt if its hot, but when things go wrong your not going to be as safe, with plenty of room on the bottom its going to be a little safer, but in some cases it could hurt you.

With RG and his TT, him and his people know whats up and thats why they use a ridgid seat, People that race nascar wreck all the time and know you want to be straped tight into to your seat, with a suspension seat your never straped in tight.

[5racer]

im the one that posted on more web site to have clearance under seat had a friend that had a 12 car seat was way to low .and it broke his co-drivers back because of it if you a heavy guy get that thing up as far as possable or your going to get hurt sooner or later look at most of the new class ones and see how high they have them the newer ones like jimco .if a suspension seat is mounted right there the only way to go as to offroad racing .but thats my oppion and everyone has there own..

[prerunner1499]

Y'all gotta remember what kind of rigs we are talking anbout here. A TT has at miminum 22-24" of rear suspension travel. Most have 26+ so they can use a more rigid seat and not get a bangback ride.
Our car has an older mastercraft, 4000+ race miles on it and its still great. We have +/- 20" of susp travel and the seat sits 4" or so off the floor. Im 5'9 @ 150 and my pop is +/-6.1 @ 190 ish and we have the car set it up for him. I just run it all the way foreward and its perfect for me. We also have it tilted backward 10-12 degrees (lay back HOLMES style). It's really is important with a limited suspension travel cars to get your seat / spine angled greater than the angle of a hit to the stops. Basically run your seats in a less perpendicular angle to allow the force of a big hit to run ALONG your spine, not just vertically from your tailbone to head. If your taller 6'+ and have head room issues with running a seat 3-4" off the floor, tilt it back, move your petals foreward, and go from there.
If that dont work, you can always hit the brakes once and a while, or give your co-driver a good beeooooch slapin' across the hemlet for not telling you about that large bump on YOUR side of the road. Might think about setting up the torsions one more outer click just to help with the preload.

[amrein1743]

I know it probably goes without saying, but seatbelts need to be TIGHT! Especially the shoulder harnesses. I have made the mistake of not having them tight enough and you can deffinately feel a difference at the end of the day. Loose seatbelts obviously allow more up/down movement which will magnify the problem.

[mfs]

mfs
The car bottomed out and was coming back up while his body was still coming down, thus maganinfing the impact on him, a solid seat would have had less force.

There used to be a old TV ad about wearing seat belts that showed the efect, they taped a egg to the bottom of a small box ( the box was just a little bigger than the egg) then slamed it onto a table, the egg didnt break, then they did it with a un taped egg and it broke.

Sure a suspension seat is more comfortable, so are shorts and a Tshirt if its hot, but when things go wrong your not going to be as safe, with plenty of room on the bottom its going to be a little safer, but in some cases it could hurt you.

With RG and his TT, him and his people know whats up and thats why they use a ridgid seat, People that race nascar wreck all the time and know you want to be straped tight into to your seat, with a suspension seat your never straped in tight.

this is not a very good example at all because he had hes seat belts on. so hes still a egg taped down. seat belts in a passnger car pull out longer(theres a tread that brakes under the right load) in a cash to lessen the impact on the driver they are not reuse abale.so its still not making sence to me. are u talking about whip lash, because of the little bit of movement the driver moves in the seat? the sparkco seat has a 2-3"cushion at the bottom so it moves a little two. the probelm i think is hitting anything in the car like your head on the cage.
nascars hit walls and other cars and high speeds. rolling a car in wide open desert and hitting a wall at 200mph is 2 diff. things.
a am not trying to agrue i just want to know the facts.
that gives me a idea: maybe i will do a real test soild mounted egg vs egg in a cushion.

[ChuckH]

The car bottomed out and was coming back up while his body was still coming down, thus maganinfing the impact on him

If you dont get that then you wont ever understand, you thought a solid seat would have been worse when its not in this case.

Dez crashes dont just happen on flats, often your impacting into a hole or ditch, pretty close to hitting a wall, plus dirt grabs even if the ground is flat if you catch just right, look at what happens to Outlaws racing on dirt when they crash, watch some Outlaw's sometime and see how dirt can make for a worse crash ( even when they dont hit a wall)

As long as the seat dosnt bottom most people will be Ok in most crashes with a suspension seat

[FlyHiFlyLo7]

Just shove a big block of 20a foam between the seat and floor pan.

[5racer]

I know it probably goes without saying, but seatbelts need to be TIGHT! Especially the shoulder harnesses. I have made the mistake of not having them tight enough and you can deffinately feel a difference at the end of the day. Loose seatbelts obviously allow more up/down movement which will magnify the problem.


i kinda disagre i used to run harness tite and i would be beat to hell after a race so i started running about a 1/2 inch gap and what a differance it made .and no in a crash a 1/2 inch will not let you come out.seat belt i run tite but not over tite.

[ChuckH]

Quote

The usage of loosened seat belts has been an ongoing controversy with drivers in the Super-class categories for a number of years. Many drivers have fallen into the practice of competing with the five-point shoulder system not properly used in an attempt to improve finish-line vision. Many racers, fans, and officials have noticed this on a regular practice, and the NHRA Technical Department has released a clarification to the proper usage of seat belts.

According to Bob Stroud of Stroud Safety, "A racer does not understand the importance and safety function of wearing the seat belt as tight as possible. We have to assume racers are halfway intelligent, but this is proving they are not. They all believe they are not going to crash, because they are racers. That is a hard philosophy to get past."

A quick-release, three-inch shoulder harness meeting SFI Spec 16.1 is mandatory in all cars in competition required by the rules to have a roll bar or a roll cage. The seat belts must be used according to the manufacturer's suggested usage with the lap belt and shoulder straps tightened. Under manufacturer's warranty guidelines, the warranty is voided if the seat belts are not used properly, including "being snug to the driver's body."

Len Imbrogno, Director of Sportsman Racing & Member Tracks added, "This situation on the race track is getting worse, not better, and NHRA needed to step in and remind the racers to tighten their seat belts. We have implemented a program to check for such infractions and will have officials at the head of staging, burnout area, and standing on the starting line checking for proper seat belt usage. If the problem does not fix itself soon, NHRA will be forced to take further steps in the near future."

[ChuckH]

While were at it this is a good read on mounting belts

http://www.simpsonraceproducts.com/safety/safety.aspx?page=restinfo_seating

[mike_hinson]

I appreciate all the dialog. That is why I posted here. All of your comments have been very helpful. To put the record straight, my belts were as tight as I could get them. I re-tightened them after the first couple of miles on the first lap and every once in a while as I pounded the seat. I weigh between 195 and 200 lbs. The seat mounts were installed by the chassis builder when I purchased the frame. The belts were installed per the Simpson diagram in the post above.

The only thing so far that may be a problem is the distance between the bellypan and the bottom of the seat, which is about 2". I can raise the seat mounts, but not too much or we will be hitting the roof. As you can imagine, it is very tight in a 9 chassis. As I noted in my original post, we have bottomed out before, but not as severely. I also need to work on the suspension setup. As the car is now setup, I can not keep up with the fast guys in the rough sections. My problem with setup is: Is the car too soft or too stiff. I have to find the sweet spot.
Mike Hinson

[jcarius]

Mike,

I understand the mounting room problem. We run two 9 cars, and I'm 6'5" with most of my height in my torso. This means we mount our seats lower than we ought to. I originally ran a mastercraft seat in my car. During just the normal gyrations of a race, I found that the seat gave enough that I was feeling the floor pan. After pulling apart the seat to see what was what, I will not run one again ... the support for the seat bottom seems way too soft and weak for my tastes. I've since moved to beard seats in both cars. The seem to be better as far as support, but I'm sill paranoid - I'm going to look at the sparco seats. Also, for what it's worth I wadded up my wifes car a few weeks back - fairly serious endo at 65-70 mph. The only reason I got hurt was the seat I was sitting in (an older beard wide style) had the actual tube frame fail, effectivly loosening my harness. Trust me on this, in a serious impact, you want those belts tight!

Jim Carius

[ELITE10CAR]

This is a very interesting topic...one we at Elite have discussed several times (we have a class 10 car). Basically the topic came up because we have noticed several Trophy Trucks use a "solid" carbon fiber seat. While I do understand the points made here about a severe bottom out and how your body wants to keep going when your chassis reverses direction. If you have enough clearance between the bottom of the seat and the chassis, the problem would be solved. My problem with a solid seat is that it doesn't give at all. What about the several hundred mild-medium hits throughout the race. I feel that the "cushion" of a suspension seat has advantages over a solid Sparco. I would really like to hear from someone who has a non suspension seat to hear their first hand knowledge. I can only speak from first hand experience with a few seat manufacturers. We used to have brand "M" seats in our car. After about a year we switched to PRP. Comfort wise there is no comparison. The fit and comfort of the PRP is far superior. The strength was tested when I flipped/rolled my car going about 70 mph in Plaster city. The seats worked perfectly....no problems. I wear my belts as tight as I can as I feel that it is uncomfortable to move in the seat at all. Needless to say we are soon building a new car and anything from here on will have PRP seats.

[Brandon_Charley]

I've read threads about people breaking their backs when the suspension seats do this which is why our ranger is definately getting sparco seats. If I have to choose, I would much rather have a slightly sore back after every race than risk having a broken back after one.

[Josh_K]

http://home.att.net/~f1race43/hooker.htm

If you REALLY what to get your self in the seat check out the site above. I had them in my Pitts when I was into flying acro. They work really well and the quality is the best hands down.

When you fly acro really hard you could be pulling up to 10g's pos and in less that a secound be pushing 6 or 7g's neg. This is only belt system to use. They work so well you can turn your legs blue!

Josh

[ELITE10CAR]

Do the people who run sparcos notice any difference in ride?? Is it a better or worse ride in general regardless of what happens in an accident?

[class7s]

If you can't get enough clearence between the seat and the floor without headroom clearence you may have to have the chassis builder add some more headroom on the frame. I was looking at some class 9 frames not too long ago and all of them were way too short for me.

[movindirt]

mfs
The car bottomed out and was coming back up while his body was still coming down, thus maganinfing the impact on him, a solid seat would have had less force.

There used to be a old TV ad about wearing seat belts that showed the efect, they taped a egg to the bottom of a small box ( the box was just a little bigger than the egg) then slamed it onto a table, the egg didnt break, then they did it with a un taped egg and it broke.



What if you put a weight on top of the egg? If I wasn't in the middle of buying a house and moving then I would do the experiment myself. I know an egg is fragile but it is also a single structure except for the liquid inside. A person on the other hand is made of many structural parts, ie bones. The thing with people is you have the weight of your head pushing down on your spine. Then you add in the weight of a helmet and things get worse. I think you may never break you back in a solid seat but the long term damage could be very bad. But also as ChuckH has pointed out a suspension seat that bottoms on the floor tends to do it at the worst time, as the car is going back up. Also as others have pointed out mounting angle is important. I think this is a great disscusion. Maybe someone can do some testing that will show what is the best way.

And don't forget how important head room is. Even with your belts tight you will move and if you land square on your lid you want room. Trust me I know first hand.

Tony