cheapracer wrote:
For a comparison a Lotus Elise is 1600lbs (650 fr/950 rear) and ideally runs around 25/28 and they would be one of the lowest pressures for a production car in the world, I happen to know that Smart's are 29psi all round (they are also 1600lbs but would be softer sprung and higher sidewall than a Lotus).
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Keep in mind, the front tires on an elise are an 80 load rating (looked it up on Tirerack) which translates to 992 lbs at their max pressure of 44psi. They also have to allow for the downforce the Elise crates at speed.
Smarts come with 74 and 77 (827lbs and 908lbs respectively).
I'm also not sure if there's an absolute minimum inflation for a tire regardless of weight. I do know what happens when one is run too low for a while, and it is not pretty. Turns the inside of the sidewalls to dust and crumbs.