ATV race Los Angeles

[X8photography]

Couple pics from a ATV race.
first time shooting a race.

[SmartWombat]

Nice action, who are they racing, is it against the clock?
At 1/640 second I think the shutter speed is a little fast for movement, there's only a little blur in the tyres.
At 1/1000 you've frozen the dirt kicked up but frozen the action too.