Day 13: Fighting the cold

All week I have been wating for the cold weather to break so I can head south. Light snow and the threat of single digit temps have kept me basically winterbound in Tennessee. There are a couple of reasons that I don't like going out in winter weather.

Cold enough to need a block heater for a diesel, but the Evora starts right up

Summer tires can crack when exposed to cold temperatures. There are many reports of tires failing from simply being exposed to cold temperature. Summer tires are also designed to work over a more narrow heat range and they usually have a lower void area. That's good for dry traction on the track, bad for everything else. Each day below freezing, I inspect the tires for cracks. I have found none.

The coldest temps that this car has ever seen

The above pic shows the warmest morning temp of the week, my best chance of getting out of town. Since it's well below the 'supported' temps for the tires, I took it very, very easy for a few miles.  Front tire pressure is down from 31 psi @ 100F to 25psi @ 15F, not far from what you would expect from the ideal gas law (the Earth's atmosphere is a mixture, not an ideal gas).  After about 10 miles, the pressures have built back up to 30psi, which indicates the the tire carcass (and air inside) has warmed up significantly, despite ambient temps of 17F. I drove almost 200 miles once they were warm, making a bee line for warmer weather.