So i was on Facebook and i came across this company that makes running boards for trucks and suvs , jeeps etc. that hold actually a lot of air, here are the numbers the owner told me
Wonder what the pressure ratings are. Running boards on long chassis vehicles are a primary impact point when going off-road so I’m not sure it’ll suit anything other than pure on-road trucks, but it’s a neat idea I guess.
their website claims up to 14 gallons and up to 180 PSI. They say they use 1/8" thick steel for the tanks, but this seems a bit too thin if you ask me.
I am also skeptical of the safety aspects of these; a minor collision could result in an explosion.