Cash Cow

I have searched this site for tires, and the more I search, the more confused I get. I currently run the crappy Hancook Dynapro AT2 275/60/20 tires on my 2017 Limited. If I wanted more rubber for a softer ride, what is the largest 17, 18, and 20 inch tire I could install without any modifications. Appreciate any input.

WVMoose

iTrader: (2)

33x11…convert to metric version for the wheel of your choice.

close thread, lol

BadAV

Converting Metric to inches:

[(275X2)/25.4]X0.6 + 20 = 32.99"

This formula can be used for any size tire/wheel combo. 275 is tire width, 0.6 is tire aspect ratio, 20 is rim size. Yes, I am a nerdy engineer. 🤷

Edit:

As a comparison, my 2015 came with 275/55R20 Hankooks (31.9"). I swapped to 17" rims to get more sidewall, for a better ride and better off road protection. I bought P285/70R17 (32.7"). I am going to replace these tires next year and have decided to go back to stock height tires to gain back the 1.5 mpg lost when I went to the taller/heavier tire. So looking at 17" tire sizes to get as close to a 31.9" tire as I can, I decided to go with a P255/75R17 (32.06"). I don't want to go shorter than OEM height.

mulyhuntr

I doubt the juice would be worth the squeeze. 285/75-17 load c rides worse than oem 275/65-18, but that could be the level and bilsteins.

You should be able to fit close to a 34 assuming stock offset.

Boomerweps

Are you using hand calculations or going by the truck computer for your mpg difference?
You can use FORSCAN to input any factory size tire (or use a same outer diameter tire as your new tires) for MPG and odometer corrections. I expect to get another summer out of my stock tires and plan on mildly upsizing on my factory 20” rims. I run winter treads on 18” rims with a similar OD.

BadAV

In my case I compare my gps indicated speed to the digital IP display (I have found the digital display is the one that matters for mpg calculation, etc - my analog display is almost 1 mph off from the digital) and adjust tire size with my handheld programmer (or HP Tuners) until the digital display and gps agree. I observe both displays with cruise control set on flat highway drives.

allinon72

If your true goal is a softer ride, load range is what you want to focus on, and most larger off road tires are E, with a few sizes closer to stock being D. These will result in a stiffer ride despite having more sidewall.

mbrick

Avoid any LT or extra stiff tires.

The original 18" are 275/65R18. Users report a 275/70R18 fitting without any modification which buys more sidewall. But, some models only come in a heavier LT tire at that size that will be stiffer.

I just switched from stock 20" to stock 18" size. I only have a few low speed miles on them so far so I can't say whether they are noticeably plusher.
I also have stock suspension and I feel like some better shocks would help with the sharp bumps.

LORDV8R

Another factor when changing tire sizes, and wanting the same as or better mpg, is the weight of the new tire. More rolling weight equals lower mpg.