Further to my post titled OE Spare, I have been given conflicting information about tire replacement. First of all, I understand mostly about tires but maybe not so much about all the electronics they can affect. I've been told by some that it would be okay to repace two tires on the same axle as the others only have 19,000 miles on them. I have also been told by someone who used to work for a GM dealership that it wouldn't be a good idea because of all the electronic sensors that monitor the truck and all of its parameters. ( FYI, the reason I need to replace is that I got a sidewall puncture-7/8" spade drill bit of all things.) I don't really want to replace only only one, as if I replace two, I can keep the other slightly used tire for a full sized spare.The GM guy says to replace all four. Any input greatly appreciated as always. Thanks.