New superduty - 18" or 20" wheels

Lynnmor wrote:

Grit dog wrote:

Lynnmor wrote:
A larger diameter tire will have the same effect as a higher gear ratio. You choose what is the most important; pulling power or looks.

has nothing to do with rim dia, only OD of tires.
No diff between OE 18s and 20s other than looks and cost of tires.

The difference is about 7% which is the difference between the 3.31 and 3.55 gears offered by Ford. Whatever makes you happy, but I chose the 18" with the 3.55 gears.

It is actually about 3%. Ford uses 275/70 R18 or 275/65 R20 tires. Circumference difference is approximately 2.8% larger. Revs per mile difference is 2.7%. So that would make the 3.55 effectively 3.49

KTMsc wrote:
I wanted more tire for a better ride than the 20s.

I would have gone for the 20s because I think they look more size appropriate for the truck. I have the 18s and the truck still rides really hard when empty so maybe 18 is better is you travel empty often.

20's with 3:55 gears and I have no power issue at all, but im also diesel. the od of the 18 and 20 are the same, the theory behind it is a slight lower profile which will get a little less sidewall flex and better handing. the Michelins on the truck have the same load rating whether 18 or 20.

Grit dog wrote:

Lynnmor wrote:
A larger diameter tire will have the same effect as a higher gear ratio. You choose what is the most important; pulling power or looks.

has nothing to do with rim dia, only OD of tires.
No diff between OE 18s and 20s other than looks and cost of tires.

The difference is about 7% which is the difference between the 3.31 and 3.55 gears offered by Ford. Whatever makes you happy, but I chose the 18" with the 3.55 gears.

Lynnmor wrote:
A larger diameter tire will have the same effect as a higher gear ratio. You choose what is the most important; pulling power or looks.

has nothing to do with rim dia, only OD of tires.
No diff between OE 18s and 20s other than looks and cost of tires.

KTMsc wrote:
Ordered my 2015 F350 with the 18s and they are rated at 3640 payload per tire.
Not sure on the payload of the 20s.
I wanted more tire for a better ride than the 20s.

The max load rating for the OEM Michelin 20" tires is 3,750. Had one truck with the 18" tires. Last 2 trucks both with 20" tires. No noticable difference in ride.

mich800 wrote:
The performance difference is not nearly as dramatic as some would like you to believe. It seems like some see 20" and see some huge difference in net size. In actuality the difference in total diameter is a little less than one inch or right around 1/2 inch difference in sidewall height.

^ THIS! rim size is just rim size. What matters is the tire's overall measurement. The tire sizes are extremely similar and really don't affect much as to a fart in the wind. Overall diameters are similar. Now what makes a difference is the hit in the ol' wallet when it comes time to replace a tire. Typically, a lower profile tire will cost more than the taller sidewall tire. Go to tirerack or wherever, input a super duty, and then check out tire prices for both OEM sizes. Also note, tire capacity is roughly 3,800 lbs per tire on the 20" rim (I bought the OEM superduty sized tire for my F-150 when I wanted a cheap taller tire and it was the cheapest 34" tire I could find) versus the previously posted number for the 18" tire.

The performance difference is not nearly as dramatic as some would like you to believe. It seems like some see 20" and see some huge difference in net size. In actuality the difference in total diameter is a little less than one inch or right around 1/2 inch difference in sidewall height.

A larger diameter tire will have the same effect as a higher gear ratio. You choose what is the most important; pulling power or looks.

Ordered my 2015 F350 with the 18s and they are rated at 3640 payload per tire.
Not sure on the payload of the 20s.
I wanted more tire for a better ride than the 20s.