Well, shooting at a static tire is useful info gathering - yet, actually what happens to bullet activity at the instant it hits (a) a tread; (b) a sidewall, when it is rotating at "n" amount of RPM relative to tire size and vehicle speed???
I often wondered if a tread hit at speed(?) while pursuing would possibly spin the round upward and not penetrate at all, or maybe bounce around hitting a gas tank. Maybe the 5.56, pointed as it is would penetrate (if it didn't fragment. But hanging an AR out a window at speed - odds aren't good.
FWTV - For Whatever The Value
...When seconds count, most help is just minutes away.