Lonely runners

n runners are on a circular track of length 1.
At t = 0, they are all in the same position and start to run in the same direction.

A runner $R_i$ is said lonely at time t if he is at a distance of at least $\frac{1}{n}$ of every other runners.

There are 10 runners with the following speed : $13,163,353,389,487,491,563,797,857,881$
A speed $V_i$ means that the runner $R_i$ completes the track in $V_i$ unit of time.

At which time all runners have been lonely at least once?
(The time t is discrete and should always be an integer)