I have a pair of firestone air bags that I cant seem to find any info on .  The number on the bag is 20c.  I was thinking of using these over the axle on my mazda but I don't know if they will work .  Any info would be great.  Thanks
      
                        
                      
                             
      
            
            
        
    
    
    
        The Firestone 20c part is a really big part. It should be about 9" across if I remember correctly. You can run them directly over the axle with tolerable results, but honestly you truck doesn't weigh enough for those bags. A fullsize 4-door doen't really weigh enough...
    
      
                        
                      
                             
      
            
            
                            Your right they are big and about 9 inches across.  Thanks for the info