New Tires? 275/65r18 275/70r18 or 285/65r18

[haresource2]

Time to get new tires. I replaced the 20" factory wheels with 18" for looks. The 275/65r18 is an inch shorter than the 275/60r20. Would I be better to go to a taller tire for highway efficiency? I was looking at 275-70r18 or 285-65r18. Both would bring me back to about the 33" height. Would the 285s cause greater rolling resistance. I'm only really concerned about the efficiency at highway speed 70-80 mph. Also Its hard to find 275/70r18 that is not a load range E, which is heavier.

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[Jajar1124]

Are you getting better efficiency with the 18s? Considering going from 18 to 20.

 

[haresource2]

Are you getting better efficiency with the 18s? Considering going from 18 to 20.

I have no clue if its better or worse. Overall running around 2.1 mi/kwh, 1.8 at 75 mph. My speedo was never adjusted so it might be a little worse. Based on tire sizes my speedo is off by 2.8%. Cruise at 80 mph, real speed 77-78 based on gps.

I was wondering if larger tire diameter was more efficient. I would assume that the stock tires on 20" rims would provide the best efficiency for the er battery since Ford picked that.

 

[neonoggie]

Hi guys, new member here.

My initial guess was that the larger diameter tire would be less efficient because of increased weight and rotational mass, plus a slight bump in frontal area of the truck. But these effects are probably small compared to the different aerodynamic profiles of the wheels and tires.

I assume Ford puts 20s on the higher trims because bigger wheels = more premium for most people. However, the 20s seem to have a more aerodynamic profile than the 18s so my guess after a bit more thought is that they probably have similar range with the same tire attached.

 

[haresource2]

Well I went with the 275/70r18 load range E. I think it looks a lot better. The 275/65r18s looked a little small. Only 50 miles on them so far and ride seems to be the same. Speedo is now dead on. No interstate driving but mi/kwh seem to be about the same.

 

[Ford Motor Company]

Well I went with the 275/70r18 load range E. I think it looks a lot better. The 275/65r18s looked a little small. Only 50 miles on them so far and ride seems to be the same. Speedo is now dead on. No interstate driving but mi/kwh seem to be about the same.

We love it, Mark! And that is a stunning F-150 Lightning! Thanks for sharing.

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