I went to a free demonstration put on by BMW where they had us race some of their cars (mainly M3s) around a parking lot marked off by cones. Certainly not real racing, but they were still changing out the tires *every 2 hours*. And I noticed that a couple of the cars were making somewhat ominous ticking sounds by the afternoon. Didn't strike me as an inexpensive hobby. Hopped back on my bike afterwards to ride home on the $5 tires that last for most of a year.