hi folks need info on which tuner would be best or which can reflash for tire size change (toyo m/55 10ply 285's a great and real 4x4 tire). I have a stock 2004 lly 2500hd 4x4 crew cab. do they all recalabrate the trany and brakes. how close will speedo and odomiter be. i have gps and now at 65 on the speedo the gps is 70. i tried to have the dealer do a reflash but it didn't work after i paid $75 it did help some (shifting and brakes)but still not right,when i took back to him for service i told him it was still off then he said they can only do a reflash for 265's. With the stock tires i could go 450 miles and the odomiter would be off from gps 4/10 of 1 mile. Now im bumming trany not shiffting right brakes fell odd. im not looking for a race truck. I do have trailer (9000#) i pull . some extra milage would always be nice along with a little hp. i make a trip to the river 2 or3 times month 175 miles each way unloaded so i try to keep it at 79 mph if you hit 80 its tickit time so i like the mph to be close and don't like having the gps with me all the time. im leaving the truck stock other then the tuner. if they would put real tires on at the factory i would not have to put up with this bs

from what i heard that GM can only calibrate the speedo up to 265's. You might want to look into buying a Predator or you can also get a Edge juice with the attitude so you can have a display of how fast your going on the attitude display but the speedo on the truck will still be incorrect. Good luck. P.S. if you are towing a 9000 lb trailer i would definitely buy a programmer, makes the hills seem alot smaller.

Good luck.