Why do rally car racers have a co-driver?

Question

i see that the co-driver is giving directions..but doesn't the driver know what's coming up and what to do? sometimes they show the co-driver and they aren't even saying anything. are they really necessary?

Answer 1

You have to remember.. these guys aren't going around a track they can burn into memory. The navigator tells them whats coming ahead and how hard the corner is.

Without a navigator.. the drives would run off of any blind corners.  

Answer 2

A good navigator is not only necessary, they are essential. In rally races you tend to be covering sizeable distances which are non-repetetive. This is very different from NASCAR (left turn... left turn... left turn..) and F1 where it is many laps over an existing track.

I've done a few rally races over the years, and the navigator is responsible for knowing exacly what is ahead, they guide the driver through their present track issues and with that information ensure that the driver is correctly positioned for the next part of the track.

In modernterms, if you play racing video games, a friend to tells you in advance of the turn you have to navigate makes the game much easier. This is the same with rally racing, the foresight of the navigator allows the driver to focus on what's in front of them, but still have active input on what's ahead.