Most servos and speed controllers come with a wire that is too long for the average RC car. The usual way to deal with this is to either make a spiral by tightly wrapping the wire around a pencil, or by carefully bundling the wire up and securing it with a zip-tie.
A better way, albeit requiring more effort, is to shorten the servo wire to the exact length needed. The unused length of wire is just ballast, and also restricts current flow.
This post shows you how to shorten servo wires.