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I had noticed in a couple of my in-car videos that my seat flexes laterally during turns. I had assumed that it was within normal limits for the seat design (Sparco Pro ADV). It is an an FIA 8859-1999 and not intended to be used without a back brace. Someone pointed it out on my most recent video so I thought I better check. The seat is mounted using Sparco mounting hardware on a Sparco slider.
Vid… http://www.youtube.com/watch?v=m7CI6zos_0w
Thanks,
Andy
I looked at the seat assembly today and it looks like most if not all of the movement is coming from the slider mechanism. There is a little bit of flex in the seat, but the slider has a lot of laxity in it. I checked all the mounting bolts were properly tightened and they were. The passenger seat sliders also have a lot of movement. Either I installed them incorrectly (which would be difficult to do, but I can never underestimate my own incompetence) or that is normal for the slider.
Should I take the seat off the slider and mount it directly the floor? Is anyone else using sliders?
Thanks,
Andy
Looks normal. Now THIS is excessive flex :woohoo:
[quote=“greensha” post=66179]Should I take the seat off the slider and mount it directly the floor? Is anyone else using sliders?
[/quote]
I use sliders. I get comments to my videos from the amateur internet forum imaginengineers saying my seat flexes too much. Ask IndyJim, I am Safety Sally. Here’s how I see it.
Composite seats are designed to flex. Sparco sliders may add a bit of movement to the lateral flex. I am not concerned that the sliders would break free. I trust Sparco products.
As long as you don’t have cage bars too close, there is nothing bad and a lot good about seat flex. In an impact, I want as much stuff dissipating energy as possible (car body, seat, that extra 10 lbs I carry around). If my seat is absolutely rigid and tied to the cage, my body has to dissipate all that energy.
I will never run a composite seat with a back brace unless it is something like RaceTech’s version that was designed and tested to have one. Add a back brace to an outdated composite seat? Dumbest. Safety. Rule. Ever.
Oh, by the way this is simply my opinion.
[quote=“Steve D” post=66202][quote=“greensha” post=66179]Should I take the seat off the slider and mount it directly the floor? Is anyone else using sliders?
[/quote]
I use sliders. I get comments to my videos from the amateur internet forum imaginengineers saying my seat flexes too much. Ask IndyJim, I am Safety Sally. Here’s how I see it.
Composite seats are designed to flex. Sparco sliders may add a bit of movement to the lateral flex. I am not concerned that the sliders would break free. I trust Sparco products.
As long as you don’t have cage bars too close, there is nothing bad and a lot good about seat flex. In an impact, I want as much stuff dissipating energy as possible (car body, seat, that extra 10 lbs I carry around). If my seat is absolutely rigid and tied to the cage, my body has to dissipate all that energy.
I will never run a composite seat with a back brace unless it is something like RaceTech’s version that was designed and tested to have one. Add a back brace to an outdated composite seat? Dumbest. Safety. Rule. Ever.
[/quote]
Steve and I are in perfect agreement. On our beer of choice. On everything else we generally disagree. IMO the priority for the seat and harness is to keep the driver restrained. My perception is that accident investigator/safety engineer types say that the most deadly thing in a crash is that the car’s occupants fly around and hit things, and that preventing the person from flying around and hitting things inside of the car in a wreck is a helova lot harder than we think it is. If we see a seat noticeably flexing from the nominal g’s of hot laps, imagine what the seat would do if the g load was 50x more. I think that a flexy seat significantly adds to the liklihood that the a driver’s body might find a way out from under the harness. Sure to us that seems impossible, but maybe an accident investigator would tell us that we underestimate how easily the flexible human body can wriggle out from under a belt in the violence of a crash.
I agree that it would be nice for the seat to absorb some impact energy, but you don’t see flexy seats in NASCAR nor F1, so maybe flexy is over-rated.
All the bolts on the seat are tight. Most of movement is coming from the slider mechanism. There is a little bit of flex in the seat. I suppose the real concern would be the sliders failing to hold the seat in an impact. I have not been able to find any instances of sliders failing during a crash. The movement is not noticeable when driving.
A.