Not all that long ago, a 19-inch wheel was a considerable upgrade available primarily in the aftermarket. But as the arms race to present bigger and badder-looking wheels took hold at OEMs, the wheel sizes have shot up, with factory-available sizes above 20 inches now fairly common. But most of those huge wheel and tire packages restrict buyers to summer tires that aren't worth much in cold or snowy weather.
GM is fixing that with the 2011 CTS Sedan and Sport Wagon, offering 19-inch all-season Goodyear Eagle RS-A2 tires for the first time. The upgrade will run $850 over the standard 18-inch wheel and tire package, a small price to pay for the improved looks and all-season road-holding ability.
If you're worried about the handling and performance of the big all-season, Cadillac doesn't think you need to: they've made sure the tire doesn't interfere with the suspension's dynamics, and a carbon fiber-reinforced sidewall helps deliver better feel and support than the average all-season.
You'll still lose some grip to a dedicated performance summer tire, however, but only in those months where the temperature and road conditions are in the summer tire's sweet spot. Plus you won't have to spring for a second set of wheels and tires to run when the weather makes its yearly turn for the worse.