Hello all.

So I was thinking about tires the other day when considering wether or not to upgrade tires on my 2020 XLT with 20inch factory chrome wheels-

What is it that ACTUALLY makes larger tires feel heavier and make the truck "sluggish"? Obviously having more rubber and a larger amount of revolutions will make the truck work harder, but what about the weight? Not all AT tires are created equal in this department with some weighing close to 55-60 lbs and others in the low 40lb range. A 10lb variant from stock on each corner is significant.

I see people all the time saying they went up to a 33inch or 34inch tire and "they didn't feel a difference" but I can tell you from personal experience that when I upgraded my 2016's factory 18's to 275/70-R18 (33inch) I felt the difference immediately, truck was sluggish and I wasn't satisfied until I finally tuned the 3.5 EB a year later. But they were Cooper AT3xlt tires and those push 55 lbs. If I went with say, the Toyo open country @42lbs, would I have felt the difference as much?

So what matters more? Weight or Physical Dimension Size? When looking for new tires on my 20inch, and wanting ZERO change in stock feel, should I stay stock? Or go larger but get a lighter tire.

 

Rotating mass, mostly.

Unsprung weight, also.

Within the context of a modern 10 speed F150, and typical tires we talk about and put on our trucks, the weight jump when going to an LT tire (usually E load range "10 ply) is the biggest difference in performance. Because of rotating mass. And for ride quality, that's unsprung weight as well as air pressure which people tend to bump up for LT tires even though air pressure is primarily determined by vehicle weight/load on the tire

A more 'off road' aggressive tread pattern also tends to have high rolling resistance than a street/highway tire.

 

The larger the tire diameter, the less the overall effective gear reduction which requires more torque and hence more power, resulting in a sluggish feeling. That is in addition to what has already been said.

 

I just put on a LT tires that weighs 80 lbs and didn’t notice any difference except for ride comfort. But I expected that.

 

The 20" rim by itself will not change the amount of revolutions of the tire/wheel combination.

 

I didn’t think it would. We’re talking about rubber here. I was just comparing to my 18s when I went up tire size. My 20s are still mated with stock rubber 275/55r20

 

Rolling resistance is the rubber and whatnot you must deform to have a contact patch. Higher load rated tires have more rubber and whatnot to deform.
Diameter changes the effective gearing ratio. More diameter requires more energy to get moving.
Weight is what the truck weighs, and also the rotational mass. More of either takes more energy to get moving.

Diameter and weight also amplify each other. If you have two tires of the same weight, but of different diameters, the taller tire is going to take more energy to accelerate because there is more weight further from the axle than with a smaller diameter tire.

When moving up to a taller and higher duty tire, you end up with a taller gearing + more weight + less weight leverage + more resistance

You can use simple equations to compare the diameter and weight, but Weight x Diameter and Rolling Resistance would require data from the tire manufacturer.

 

The bigger the diameter of the tire, the lower the effective gearing. Lower gearing generally means slower acceleration, though the 10 speed transmission may compensate for this somewhat.

The heavier the tire, the greater the rotational inertia. It's takes more torque to get the tire rolling and more torque to slow it down.

The heavier the tire, the greater the unsprung weight. This taxes the suspension reducing control and comfort.

The wider the tire, the greater the rolling resistance. It takes more torque to move and keep it moving.

The more aggressive the tread pattern, the greater the rolling resistance. It takes more torque to move and keep it moving.

 

I went from 18" stock Michelin Primacy passenger tires weighing 40lbs to stock size General Grabber AT/x LT tires weighing 60lbs and there is no noticeable difference regarding power. I understand going bigger than stock, lifting etc. will start deteriorate performance.

Side note I run the LT at 44psi and they are A L M O S T as quite at the crappy highway tires that came with the truck. That being said I will probably go back to the Primacy in the spring just to save mileage on the Grabbers for next winter.

Flame on haters

 

Moment of inertia
google it