PCA seat rule
10-25-2006, 09:27 AM
#19
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Hey;
The seat back brace rules are an attempt to cover for the inherent deficiencies in seat mounting that less than full on custom built race cars often create.
In a serious race car, you have tube structures tied into the chassis that exist for mounting the seat solidly. The solid mounting of the seat puts the onus on the seat itself, as it will be the weak point.
In our converted street cars, we have whatever the factory built for a much lower standard. Even the Cup Cars are no different. While they use good mounting hardware, they still mount to a tin floor. When you start dealing with sliders, or home grown mount plates, the potential for problems magnifies. Mr. Colhoun's ("Rick") event made that painfully clear. Unfortunately, we saw that he had neither a good seat, nor mounting for it.
The SBB is not a perfect solution, and carries its own set of problems. However, short of tubing everyone's floors, it is a decent and versatile compromise.
The seat back brace rules are an attempt to cover for the inherent deficiencies in seat mounting that less than full on custom built race cars often create.
In a serious race car, you have tube structures tied into the chassis that exist for mounting the seat solidly. The solid mounting of the seat puts the onus on the seat itself, as it will be the weak point.
In our converted street cars, we have whatever the factory built for a much lower standard. Even the Cup Cars are no different. While they use good mounting hardware, they still mount to a tin floor. When you start dealing with sliders, or home grown mount plates, the potential for problems magnifies. Mr. Colhoun's ("Rick") event made that painfully clear. Unfortunately, we saw that he had neither a good seat, nor mounting for it.
The SBB is not a perfect solution, and carries its own set of problems. However, short of tubing everyone's floors, it is a decent and versatile compromise.
10-25-2006, 11:23 AM
#20
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Originally Posted by fstockcarrera
The STREET(not fia) seat rails bent and the seat back resting on the cage horizontal cross brace broke Rick's seat back(not Fia rated) at the base of his helmet and ........... you know the rest. Most seat back braces would not have saveed his life. IMHO. Rick backed perpendicular into the pit out guard rail @ at what is estimated 90 mph. There was no give to the guard rail as it was back filled by earth. That's a lot of G's to stop in about 2' of space. Replacing Fia steel rails after 5 years is nuts.
Bob
Bob
How did the rails bend? Did they spread and allow the the captured foot to escape? Or did metal separate in tension or shear?
I agree. The life of a composite seat is in no way related to the life of a steel part. Are the rails even 'approved' along with the seats? This is akin the the stupid 2 year belt life foisted on everyone.
10-25-2006, 11:51 AM
#21
Mr. Excitement
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2? is it 2 or 5?
The seat mounts that come with race seats and go between the seat and rails if used are most often not steel but plate aluminium bent 90 deg. This is also under the 5 year rule per the scrut I was talking to.
The seat mounts that come with race seats and go between the seat and rails if used are most often not steel but plate aluminium bent 90 deg. This is also under the 5 year rule per the scrut I was talking to.
10-25-2006, 12:51 PM
#22
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[QUOTE=John Brown]This is interesting. Had always thought the seat failed.
How did the rails bend? Did they spread and allow the the captured foot to escape? Or did metal separate in tension or shear?
I believe the caputured foot partially released and allow the seat to deflect enough to impact the cage. I do not think the floor or the mounting failed.
How did the rails bend? Did they spread and allow the the captured foot to escape? Or did metal separate in tension or shear?
I believe the caputured foot partially released and allow the seat to deflect enough to impact the cage. I do not think the floor or the mounting failed.
10-25-2006, 01:48 PM
#23
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[QUOTE=fstockcarrera]
Wow. Incomplete data. However, it appears that an awful lot of change may have been promulgated based on flimsy evidence. Nothing in what you share, so far, suggests that the age of the rails had anything to do with anything. Nor that 'non-stock' rails would perform better. Why? In what manner?
It's been suggested that one could simply order new rails etc every 5 years, return unused, keep the orignial reciept. Sounds good to me.
Originally Posted by John Brown
This is interesting. Had always thought the seat failed.
How did the rails bend? Did they spread and allow the the captured foot to escape? Or did metal separate in tension or shear?
I believe the caputured foot partially released and allow the seat to deflect enough to impact the cage. I do not think the floor or the mounting failed.
How did the rails bend? Did they spread and allow the the captured foot to escape? Or did metal separate in tension or shear?
I believe the caputured foot partially released and allow the seat to deflect enough to impact the cage. I do not think the floor or the mounting failed.
It's been suggested that one could simply order new rails etc every 5 years, return unused, keep the orignial reciept. Sounds good to me.
10-25-2006, 04:13 PM
#24
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I was doing tech at the Porsche 50/50 at the Glen, and most race cars I checked with sliders had VERY worn out sliders. Many only have stops on one side (the other is free). If you don't need to share your car with a taller or shorter driver, please mount your seat to the chassis (not floor) solidly with no slider. If you have sliders, please check them and replace if worn.
10-25-2006, 04:21 PM
#25
Mr. Excitement
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Mike is spot on. I do Tech for Potomac and see the same thing. I am only driver of my crappy little car and the seat is hard bolted.
John. Why not use you PCA chair position and look into this? Knock some sense into it if it is an unfounded or unworkable rule.
John. Why not use you PCA chair position and look into this? Knock some sense into it if it is an unfounded or unworkable rule.
10-26-2006, 02:17 PM
#26
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Hey;
I don't think interest in seat rails is unfounded in the least. The deficiency lies in having tech people that have the time, the mandate, and the knowledge to REALLY pour over a car, look for such things, and know whether things are safe or not. It is very difficult to find that. It is the weakest link in the chain.
Seat sliders are indeed a wear item, just like wheel bearings, water pumps, rod bearings, etc. They need attention at some interval. What that is is unclear, and so someone must come up with some standard that forces some scrutiny. In that regard, I find it hard to fault a sanctioning body for choosing 5 years. It may not be the most effective or logical time frame, and I'm not sure you could come up with one for all eventualities, but it accomplishes the root goal; safer setups.
Single lock slider sets should be banned. Factory late model (post 85.5 I believe) double locking sliders, and any other suitable aftermarket double lockers, should be the minimum standard.
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It is my understanding that buckling of the floor pan had some bearing on the failure of the seat setup in the Colhoun incident. This is second hand info.
I don't think interest in seat rails is unfounded in the least. The deficiency lies in having tech people that have the time, the mandate, and the knowledge to REALLY pour over a car, look for such things, and know whether things are safe or not. It is very difficult to find that. It is the weakest link in the chain.
Seat sliders are indeed a wear item, just like wheel bearings, water pumps, rod bearings, etc. They need attention at some interval. What that is is unclear, and so someone must come up with some standard that forces some scrutiny. In that regard, I find it hard to fault a sanctioning body for choosing 5 years. It may not be the most effective or logical time frame, and I'm not sure you could come up with one for all eventualities, but it accomplishes the root goal; safer setups.
Single lock slider sets should be banned. Factory late model (post 85.5 I believe) double locking sliders, and any other suitable aftermarket double lockers, should be the minimum standard.
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It is my understanding that buckling of the floor pan had some bearing on the failure of the seat setup in the Colhoun incident. This is second hand info.
10-26-2006, 02:54 PM
#27
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I run BK seat mounts in my 944S2. Mounted directly to the floor. I hit the wall at Mosport this year. The mounts are connected to the factory bolt holes. I believe there is a small square of aluminum that is imbedded in the floor. The actual "floor" or sheet metal comes up around them. When I pulled the seat to check for damaged I found radial cracks in the "floor" area. I suspect, if I had been using stock sliders one may have broke.
10-26-2006, 03:02 PM
#28
Mr. Excitement
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Snip...
You are likely close to the truth. John B sent an email to Donna Amico at National and got an answer back. I wil let him cover the details if he likes but it is close in essence to the above and based on common sense and the fact that a rule has to cover a wide range of cars and fitment.
I have seen some weedy seat to car fitments in DE and Club Race and had to push on drivers to get them improved. This is not the norm IMO. Most folks work and spend to get things right.
Originally Posted by RedlineMan
Hey;
Seat sliders are indeed a wear item, just like wheel bearings, water pumps, rod bearings, etc. They need attention at some interval. What that is is unclear, and so someone must come up with some standard that forces some scrutiny. In that regard, I find it hard to fault a sanctioning body for choosing 5 years. It may not be the most effective or logical time frame, and I'm not sure you could come up with one for all eventualities, but it accomplishes the root goal; safer setups.
Seat sliders are indeed a wear item, just like wheel bearings, water pumps, rod bearings, etc. They need attention at some interval. What that is is unclear, and so someone must come up with some standard that forces some scrutiny. In that regard, I find it hard to fault a sanctioning body for choosing 5 years. It may not be the most effective or logical time frame, and I'm not sure you could come up with one for all eventualities, but it accomplishes the root goal; safer setups.
I have seen some weedy seat to car fitments in DE and Club Race and had to push on drivers to get them improved. This is not the norm IMO. Most folks work and spend to get things right.
