drftnmaz Posted January 25, 2012 Share Posted January 25, 2012 im interested in finding some good/better ways to mount fixed back seats in a road-reg race car... i had a quick look at schedule A (general race regs) and the only info i can find is the mounting points but be 40cm2 (about 64mmx64mm 3mm plate) and other info is on clearance to cage most common design i have seen on other race cars ive worked on is these plates welded on each side, then some 1" box section going from side to side with nuts(or maybe fresh steel tapped for thread?) welded into the box for the seat to bolt to, seems a easy way to mount, but i don't like the idea of welding a nut into the box, seems like a weak link to me? ideas please.... normally i just do track cars so it doesn't matter but this is a street car that is going to get certed, (two seater so reclining etc isn't a problem) so want to do it properly, do not want to have to re-weld anything on the floor, would turn out messy! (oh and i can't use factory mounting points due to clearance) heres a pic of what i'm sorta talking about Quote Link to comment Share on other sites More sharing options...
mjrstar Posted January 25, 2012 Share Posted January 25, 2012 how about a crush tube in the box section and a captive nut on the under side of a piece of u channel (or flat bar)that fits over the outside of box from the underneath. Quote Link to comment Share on other sites More sharing options...
drftnmaz Posted January 25, 2012 Author Share Posted January 25, 2012 so like a rivnut fitted to a u section, which fits snugly round the box section, from underneath, which a crush tube for good measure... sounds sensible and spreads the load nicely one of these\/ ? had been considering some thick crush tube welded in and then thread tapped into it, but i don't have the right tap pitch (but can buy if need be) Quote Link to comment Share on other sites More sharing options...
mjrstar Posted January 26, 2012 Share Posted January 26, 2012 yeah nutsert / riv nut (steel ones though not ali) or to save buying a rivnut gun just normal old nut captivated with a lick of weld... Quote Link to comment Share on other sites More sharing options...
smokin' joe Posted January 26, 2012 Share Posted January 26, 2012 i wouldn't use a riv-nut type arrangement for holding the seat down, in the event of a crash i am unsure whether they would handle they load subjected to . they are perfectly fine for demountable items like radiators /catchcans etc but i personally wouldn't use on seat or extinguisher mounting points. normally i just do track cars so it doesn't matter but this is a street car that is going to get certed unsure on your logic here, a track car is exposed to far more loads and risk than a road car should be?? so want to do it properly, do not want to have to re-weld anything on the floor, would turn out messy! if that picture is not the car in question, i would use the same style of crossbars and use a crushtube with the nut on the bottom, or use thick walled tube and tap a thread into it. Quote Link to comment Share on other sites More sharing options...
nvmyvl Posted January 26, 2012 Share Posted January 26, 2012 Wats the pitch on the tap you would need? Quote Link to comment Share on other sites More sharing options...
JoKer Posted January 26, 2012 Share Posted January 26, 2012 big bolt thru the floor with some 3+mm plate washers on other side : keep it simple? Quote Link to comment Share on other sites More sharing options...
drftnmaz Posted January 26, 2012 Author Share Posted January 26, 2012 normally i just do track cars so it doesn't matter but this is a street car that is going to get certed unsure on your logic here, a track car is exposed to far more loads and risk than a road car should be?? logic there is for a track car you do what you want and make it strong, scriutineers call if you pass... this is a road legal car so concerned with rules to pass the cert, and also a way that looks nice that pic is a random, car is bare so i have a clean canvas to work with... big bolt thru the floor with some 3+mm plate washers on other side : keep it simple? i can do it like this on the passengers side, but the drivers side it needs to be higher and further forward so would have to build pedestals or similar, and thought box section from side to side would make things easy to keep level tap would be M10x1.25 -and i just found one in my collection! so i think i'll go buy some or thick walled tube and tap a thread into it. Quote Link to comment Share on other sites More sharing options...
smokin' joe Posted January 26, 2012 Share Posted January 26, 2012 normally i just do track cars so it doesn't matter but this is a street car that is going to get certed unsure on your logic here, a track car is exposed to far more loads and risk than a road car should be?? logic there is for a track car you do what you want and make it strong, scriutineers call if you pass... this is a road legal car so concerned with rules to pass the cert, and also a way that looks nice that pic is a random, car is bare so i have a clean canvas to work with.... still cant see your logic. track car = hori but strong road car = nice and pretty for cert?? Quote Link to comment Share on other sites More sharing options...
Mitch.W Posted January 26, 2012 Share Posted January 26, 2012 sorry for spam but if i make some seat "rails" i mean just flat bar with some holes drilled in them to mount the seat to so its solid mounted would that pass a cert? Quote Link to comment Share on other sites More sharing options...
MK2-8-U Posted January 26, 2012 Share Posted January 26, 2012 the mounting points for the seats (as in the part that is atached to the floor) has to be 2 plates sandwiching the floor plan, they have to follow the contour of the floor pan (i think you can use cush tubes) but most rises are only like 10mm, the underfloor plate has to have radius edges and a nut welded to the plate also the 2 plates have to be rivited togther. hopefully that make sense Quote Link to comment Share on other sites More sharing options...
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