time trial

from The American Heritage® Dictionary of the English Language, 5th Edition.

• noun A competitive event in which participants are timed, as in covering a set distance, often used to select qualifiers for another event.

from Wiktionary, Creative Commons Attribution/Share-Alike License.

• noun cycling An unpaced race in which riders or teams, leaving at regular intervals are timed over a preset course or distance, the winner being the rider or team to finish in the fastest time.
• noun Any competitive event in which competitors are timed rather than racing against each other.