Thanks for the reply NowZoomer!
By chance did you mean that 285/60/20 is 33.5", and not 34.5"? According to tiresize.com, it looks like the diameter of the 285/60/20 is 1.6" bigger than stock (31.9" v 33.5"), and 1/2" larger than your 275/60/20. With your 1.5 level are you experiencing any...