I spoke with the my dealer rep yesterday and was told that changing the tires size could cause the warranty to be voided if there was any motor or transmission problems with respect to the Allison transmission! He went on to say that GM is under a lot of pressure to come up with a software solution to change the shift points on the Allison so people would have some real options without effecting the warranty. He told me he would be meeting with the GM rep in the next couple of weeks to discuss the problem...
I told him for 45K I should have some other options beside skateboard wheels and tires!
