I have m923A2. The tires Michelin 14R20. Date code 2012. One of the steers has a blemish where the tire is embossed. This tire may have deflated at one time. New these tires are expensive and no way can I afford six. I must admit I am concerned about safe operation now. Has anyone installed a substitute tire, for instance a slightly smaller tire of other manufacture? Any way this is a big problem for me.