PSA: Use load-spreading washers, please
#1
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PSA: Use load-spreading washers, please
The driver is OK. This did not happen during an event that I worked, but happened immediately beforehand and I had the chance to see the failure myself. I wouldn't usually take and share post-crash pictures, but no one was limiting access to the wreck and plenty of non-affiliated people were snapping pics, so there's nothing in these pics that isn't somewhere else on the interwebs.
What I know: a Mustang rolled several times coming down the Corkscrew at Laguna Seca. The seat was bolted through these sliders and the bolts holding the seat to the sliders ripped through during the crash.
You can see in the first picture that the rails are held to the mounts using socket head cap screws, without backing washers. The seat was held to the other half of the rails in the same manner. It's an understandable mistake - because of the slider design, there is very little room for a fastener, let alone a load-spreading washer. I actually don't know anything about the slider - whether it's stock, a name-brand, or some cheap piece of junk. If there wasn't room for the right fastener (or fastener + washer), this rail should not have been used.
Please, if you can't put a washer on a critical connection, have a good, solid think about what that could mean.
See the problem(s)?
Enhance ... enhance.
What I know: a Mustang rolled several times coming down the Corkscrew at Laguna Seca. The seat was bolted through these sliders and the bolts holding the seat to the sliders ripped through during the crash.
You can see in the first picture that the rails are held to the mounts using socket head cap screws, without backing washers. The seat was held to the other half of the rails in the same manner. It's an understandable mistake - because of the slider design, there is very little room for a fastener, let alone a load-spreading washer. I actually don't know anything about the slider - whether it's stock, a name-brand, or some cheap piece of junk. If there wasn't room for the right fastener (or fastener + washer), this rail should not have been used.
Please, if you can't put a washer on a critical connection, have a good, solid think about what that could mean.
See the problem(s)?
Enhance ... enhance.
#5
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Sliders. Are. For. The. Street.
race. Cars. Have. Fixed. Seats.
it probably wasn’t loose. They’re like that out of the box, believe me I’ve installed dozens. You hard mount a seat for the biggest driver, use pour ins for smaller drivers.
Washer wont do it, if you wanted to make this strong, I’d slice some solid bar stock lengthwise, take a 2” section, cross drill it, and use that as a “washer”.
race. Cars. Have. Fixed. Seats.
it probably wasn’t loose. They’re like that out of the box, believe me I’ve installed dozens. You hard mount a seat for the biggest driver, use pour ins for smaller drivers.
Washer wont do it, if you wanted to make this strong, I’d slice some solid bar stock lengthwise, take a 2” section, cross drill it, and use that as a “washer”.
#6
I take your point Curly, and don't disagree.
However my car (dual-duty) and my (now-defunct) racecar both had/have sliders, the factory ones - there is and was no 'slop' in them. I appreciate it may be different in different applications, and FWIW I am rather on the smaller size than the larger. If that was slop in the slider, as opposed to loose mounting bolts, well it shouldn't have made any difference - either should have been a big red flashing light for the intrepid pilote.
I hope said pilot got out of it OK, we have just had someone here shunt a GT3 with loose belts, very bad outcome, he survived but had serious injuries and faces a protracted recovery. The dynamics would have been similar, but the velocity probably greater. https://www.speedcafe.com/2022/08/31...fing-swear-it/
However my car (dual-duty) and my (now-defunct) racecar both had/have sliders, the factory ones - there is and was no 'slop' in them. I appreciate it may be different in different applications, and FWIW I am rather on the smaller size than the larger. If that was slop in the slider, as opposed to loose mounting bolts, well it shouldn't have made any difference - either should have been a big red flashing light for the intrepid pilote.
I hope said pilot got out of it OK, we have just had someone here shunt a GT3 with loose belts, very bad outcome, he survived but had serious injuries and faces a protracted recovery. The dynamics would have been similar, but the velocity probably greater. https://www.speedcafe.com/2022/08/31...fing-swear-it/
#8
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To be fair I’ve got pour-ins on the mind and maybe not the best option for everyone. My main beef is with the aftermarket sparco or recaro sliders. Pretty hard to **** it up on a Miata, you either fit or you don’t. As always, they’re always the answer.
#9
My buddy was there when this happened, he showed me the car and the bolts. The washers distribute the pulling force around a greater area of the mounting platform. Washers increase the load area by approx. 2x id say. That means if proper washers were used the seat would be twice as strong. Being that the seat tore out with half the area that washer would give that would leave us with a safety factor of < 2. Thats not enough for me. I am going to make new seat brackets. I now feel uncomfortable with how my exige seats are mounted.
#10
Sliders. Are. For. The. Street.
race. Cars. Have. Fixed. Seats.
it probably wasn’t loose. They’re like that out of the box, believe me I’ve installed dozens. You hard mount a seat for the biggest driver, use pour ins for smaller drivers.
Washer wont do it, if you wanted to make this strong, I’d slice some solid bar stock lengthwise, take a 2” section, cross drill it, and use that as a “washer”.
race. Cars. Have. Fixed. Seats.
it probably wasn’t loose. They’re like that out of the box, believe me I’ve installed dozens. You hard mount a seat for the biggest driver, use pour ins for smaller drivers.
Washer wont do it, if you wanted to make this strong, I’d slice some solid bar stock lengthwise, take a 2” section, cross drill it, and use that as a “washer”.
#11
Cpt. Slow
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Join Date: Oct 2005
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My buddy was there when this happened, he showed me the car and the bolts. The washers distribute the pulling force around a greater area of the mounting platform. Washers increase the load area by approx. 2x id say. That means if proper washers were used the seat would be twice as strong. Being that the seat tore out with half the area that washer would give that would leave us with a safety factor of < 2. Thats not enough for me. I am going to make new seat brackets. I now feel uncomfortable with how my exige seats are mounted.
id be curious to know how long ago that seat was installed, and if the bolts were tight that whole time. Rocking back and forth on a loose bolt or small surface area could have fatigued the slider metal.
#12
you should feel incredible uncomfortable with any lotus parts bolted to your car.
id be curious to know how long ago that seat was installed, and if the bolts were tight that whole time. Rocking back and forth on a loose bolt or small surface area could have fatigued the slider metal.
id be curious to know how long ago that seat was installed, and if the bolts were tight that whole time. Rocking back and forth on a loose bolt or small surface area could have fatigued the slider metal.
#13
Cpt. Slow
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Those sliders inherently have some slop to them. I check all the seats after every race, but you really need to have a 2nd person jiggling the seat while you climb under it and inspect with a flash light to see if it's just rail, or a bolt has come loose. This isn't a rarity btw, the bolts come loose more than you'd think.
#14
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I went through a lot of trouble to keep the Stock NB sliders when I installed the Corbeau-for-Lotus seats in my NB. When using factory seat belts, the inside connection runs through the slider assembly, which is specifically constructed to handle the forces involved. Aftermarket sliders will not.
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