<ALL> General question about tires

[Stephen West <stwest@xxxxxxxxx>]

     Greetings:
     
     I have a VERY basic question about tires that is not car specific.
     
     
        Assuming all four tires have about 12,000 miles, yet one of the     
        tires is losing air (about 2 lbs/psi per week).  I want to have     
        that tire replaced (left rear tire).
     
     My question is:   
       Is it OK to just replace that one tire, or should the right rear     
       tire also be replaced?  Will I have problems with un-even wear,      
       balancing, etc if I don't replace all four tires?
     
     What is the best approach when you have to replace one of four fairly 
     new tires?
     
     I would like some independent recommendations before I speak to a      
     local tire shop.
     
     thank you.
     

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