Had the new tires installed yesterday.
Old tires were 285/60/18 Nitto Terra Grapplers with 30,000 miles on them. Nitto lists the diameter for these tires as 31.46 inches. After 30,000 miles these tires were sitting at 29.5 to 30 inches in diameter when mounted with the weight of truck on them at standard recommended pressure.
New tires are 275/65/18 Nitto Ridge Grapplers. Nitto lists the diameter for these tires as 32.09 inches. When mounted with the weight of truck on them at standard pressure these tires are sitting at about 31 inches in diameter.
At standard ride height the truck is now riding about 1.5 inches higher when measured from ground to wheel well fender.
At standard ride height I've noticed definite rubbing on front frame horns while slowly turning forward with steering turned to lock and
a lot of rubbing on horns while reversing with steering turned to lock. Previously I only had a bit of rubbing on the horns turning forward when the 285/60/18s were brand new and they always rubbed a bit on the horns in reverse full lock. I also noticed some rubbing on the passenger rear inner fender liner forward of the tire at standard ride height upon hard acceleration.
I have the X-Lifter module and I usually ride around town in +25 mm mode so that takes care of the rear fender liner rubbing. I'll have to drive some more to see if I rub anywhere while driving normally at +25. On the highways I drive in standard height mode and I'll have to see if it rubs at all while on the highway. The tires are pretty stuffed in there at access height but it looks like it'll still roll. I think I'll be rubbing if I drop to the bumps. Just got my GAP IID Tool in the mail from Lucky 8. Will have to play with it some more.
I'll attach some pics.
X-Lifter on standard (+0 mm) and OEM dashboard setting at Access Height:
X-Lifter and OEM at standard height:
X-Lifter at +25 mm and OEM standard:
X-Lifter at +55 mm and OEM standard:
X-Lifter at +75 and OEM standard:
X-Lifter at +75 and OEM at Off Road Height (this usually triggers the obstacle warning saying return to normal after you clear obstacle):
![6--+75 OEM offroad.JPG 6--+75 OEM offroad.JPG](https://discoweb.org/data/attachments/55/55226-da29156fb44912efd87e7a768bf4f47b.jpg)