NASCAR balances all of its Goodyear racing tires....
Tire busters face balancing act throughout season - May 12, 2011 - NASCAR.COM
"Once finished at Darlington, mounters rolled their work to 18-year-old Devon Tucker, who in turn passed it along to one of eight people manning balancing machines under a tent just outside the mounting building. There, the balancing contraptions spin at 35 mph to give a weight readout on the front and back of the tire.
Depending on the results, clipped weights from a quarter of an ounce all the way up to a full ounce are hammered onto the rim. The tire is spun again, until the tire is perfectly counter-balanced. Each balancer initials the tire and marks it with his machine number, so that if there's a problem later, it can be properly traced."