Sharing Parent Variable With Child Objects?

I am developing a new class which is a control that inherits from the "Panel" class. In this new class, I have three objects that are generated every time I create a new instance of the class. For simplicity, I will call this class "garage" and the three objects "BMW," "Lexus," and "Acura." So each new garage has three types of cars.

how can I share a variable from the Parent class with all of it's child objects? i.e. The garage has an array variable called "tires" which all three cars use. Rather than create each car object with the tires parameter, I would just like to keep the tires parameter in the parent class so that all my child objects can use it. I know that normally the parent class should provide the child class with all information when creating the child but it would seem redundant to pass the entire tires array each time since all three cars use the same tires and the tires object never change.