Soooo, my Michelin LTX A/S are at 6/32 on all 4 with 32,000 miles on them with regular rotations. I wont be buying a new set in the immediate future as in my climate I can run them down to 2/32 with no problems. However I am starting to explore my options, and kick around ideas because I cant leave well enough alone....that and the options in my current 265/60/18 size are very VERY limited.

I was thinking about moving up to a 275/65/18. This will give me more variety, and the Nitto Terra Grapplers that I have used before and loved are also available in this size. I understand this will change my speedo readings and whatnot, Im not too worried about that as my speedo already reads 2 mph fast (reads 60, GPS, and road side speed radar thingies read 58), this may or may not work in my favor and I may just get it recalibrated just so its correct depending on how much my OCD bugs me. Anyway, with the tire change supposedly at 60 (speedo) I will actually be going 63. I know they will fit without issue as a co worker has a 2wd crew cab short bed just like my truck and that's the stock tire size on his. It fills in his wheel wells better and just looks better as well.

My concern is my gear ratio which is 3.31. Above mentioned co worker has 3.55s on his, with the V-6 non ecoboost engine. Has anyone done a size change like this, or would know how that would affect power with the small gear ratio going from a 30.52" tire to a 32.07" tire?

Also, should I decide to get speedo recalibrated if I do go up in tire size, where can I get this done, and what to ask for? Thanks in advance for any tips, thoughts, advice, or ideas.