18" vs 20" MPG on '13 FX4 EB?
03-19-2023, 11:34 PM
#1
Member
Thread Starter
18" vs 20" MPG on '13 FX4 EB?
I just switched my truck from my 20" stock wheels to 18" wheels from a buddy's F150 he pulled off and was wondering if I should notice any MPG difference? I know when I went from the stock Pirelli 275/55r20 to BFG KO2s in 275/60r20 I dropped from about 18mpg to 14.9mpg so I am assuming that switching to Nitto Terra Grapper G2s in 275/65r18 with a total weight saving of about 13.75lbs per corner should improve my MPG a bit correct?
03-19-2023, 11:51 PM
#2
The first time you switched tires not only did you go to heavier ones, you went to larger ones (32" to 33") that effected your odo--did you factor that in when calculating MPG? Now you are basically going from 33"s back to 32"s. What is the weight of the original tires verses the newest? I bet the newer is still a good bit heavier. The wheels have the least effect of everything here.
Last edited by Bryce919er; 03-19-2023 at 11:53 PM.
03-20-2023, 12:05 AM
#3
Member
Thread Starter
The first time you switched tires not only did you go to heavier ones, you went to larger ones (32" to 33") that effected your odo--did you factor that in when calculating MPG? Now you are basically going from 33"s back to 32"s. What is the weight of the original tires verses the newest? I bet the newer is still a good bit heavier. The wheels have the least effect of everything here.
03-20-2023, 10:29 AM
#4
Beeps and Boops
20" wheels are significantly heavier than the 18s. My 18" factory wheels with E-rated 33" tires weighed less than my 20" factory wheels with P-rated 33" tires of the same model.
Nitto has the non-LT Terra Grappler G2 at 47lbs and the LT at 52lbs.
https://www.nittotire.com/light-truc...ht-truck-tire/
You can use Forscan to correct your tire size, then compare your speedometer readout to a GPS speed indicated on your phone to be sure it's working right.
Nitto has the non-LT Terra Grappler G2 at 47lbs and the LT at 52lbs.
https://www.nittotire.com/light-truc...ht-truck-tire/
You can use Forscan to correct your tire size, then compare your speedometer readout to a GPS speed indicated on your phone to be sure it's working right.
03-20-2023, 07:30 PM
#5
Senior Member
A tire that is 33" when new, is going to be 32" when it has 40,000 miles on it. Not enough difference to worry about changing anything. That is true of any tire in any size. They are all roughly one size smaller when you wear them out than when they were new. You're never going to get your speedometer closer than 2-3 mph all the time. You can either calibrate it for new tires and have it become less accurate as you wear down the tires or have it off by 2-3 mph with new tires and let it become more accurate as the tires wear. It's always been that way; we just didn't know it until we got GPS's.
Most new trucks come with 32" to 33" tires. Even going to 35's doesn't change things much. Back in the day 28-30" tires were standard. When going to 33-35" tires back then made a significant difference in the speedometer. Not so much today
I've never noted that tire weight changed fuel mileage as long as everything else was the same. I've gone up as much as 15 lbs/tire and fuel mileage has always remained the same. The heavier tires did give a harsher ride, and acceleration was slower. But once up to speed it doesn't take any more power to turn a 40 lb tire than a 55 lb tire.
Wide tires, and tires with aggressive treads have much more rolling resistance which means you don't coast as much and have to keep your foot on the accelerator more. That will rob you of 2-3 mpg.
Most new trucks come with 32" to 33" tires. Even going to 35's doesn't change things much. Back in the day 28-30" tires were standard. When going to 33-35" tires back then made a significant difference in the speedometer. Not so much today
I've never noted that tire weight changed fuel mileage as long as everything else was the same. I've gone up as much as 15 lbs/tire and fuel mileage has always remained the same. The heavier tires did give a harsher ride, and acceleration was slower. But once up to speed it doesn't take any more power to turn a 40 lb tire than a 55 lb tire.
Wide tires, and tires with aggressive treads have much more rolling resistance which means you don't coast as much and have to keep your foot on the accelerator more. That will rob you of 2-3 mpg.
