ok I have a 99 5.3 gmc sierra auto 2wd 3.42 i changed from oversize tires back to stock ones well the biggest allowed stock tires atleast for my truck are 255/70/16 cooper at3s the manufactures specs say 30.08 in diameter and 10.4 wide probably not actual. Ive noticed it doesn't switch the tire diameter with a "calculated tire size" anymore do you have to factor that in? Thing is I'm still getting shift time errors like its shifting to early and on my 3-4 its shifting at like .125 sometimes.. my tune is all stock except tire change/auto scale. Where do I go from here I'm going to try and check to see if my speedo is dead on with my gps on my way to work here shortly and couldn't find how to upload that but i uploaded my log and config file truck is all stock minus the corvette servo. my tire diameter was set at 30.08 in that log. Should i just do a rollout test let the tire go a full revolution and measure the marks. truck came with 235/75/16s on it but door says 255/70/16 and tire diameter was 29.23 stock and idk if they messed with it when those tires were thrown on.... thanks for any comments or help
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