Quote:
Originally Posted by oldtamiyaphile
I find it telling that (almost) no no other MPG car has gone that route. All the current day EV's have pretty wide tyres, so I wouldn't read too much into the i3's tyre spec.
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Aerovironment had to constantly fight GM to keep them from putting wide tires on the EV-1 for styling reasons.
Unfortunately, there is no good data on belted tires in the public domain, but racing bicycles still win on narrow tires for pavement. Also unfortunately, after a century of everyone understanding the basic engineering behind rolling resistance being inversely proportional to diameter, which operates on steel wheels and ball bearings, Greenspeed published a major test of bicycle tires all based on using a small diameter roller instead of a flat road surface, completely masking the difference.
Once they lay the rubber on the road, narrow tires leave it there for support for longer than a wide tire at the same pressure. However, a belted tire does not have to distort and scrub to create a contact patch. It can have a lower sidewall, and that is important because the strength needed there is directly proportional to the radius that it bulges out with to take the pressure.