I wonder if anyone here has tested the Roadster range using different wheels. From my experience, reducing the rear wheel width from 225/45R17 to 205/55R16 increases the range as much as 10-20 %. Of course it will depend on the type of tire as well, the 205/55R16-tires I tested were winter and low-rolling resistance tires. It could also be related to the weight of the wheels, as 16" weighs less than 17". A disadvantage for the driver is that the car gets less stable and more easly drifts to the side. I was thinking about 135/80R15 on the front wheels and 185/60R16 rear wheels. Is it insane to reduce the tire width this much, will the car be impossible to drive? Of course this is not for high speed driving... How much range increase could this give? How much does it depend on the type of wheel keeping the width constant? From the rolling resistance tests I have seen, the range will change only 2 %.