Went from stock 20's to stock 18's

[GunRack]

The Pro's 18's are the way to go IMO, lighter, more sidewall, cheaper replacement tire. So I swapped my XLT's 20's with the stock 18's. Would have ordered from the factory like this if it was an option. I swapped the TPMS out of my 20's into these so I didn't have to reprogram them. However the truck is still expecting 42 PSI where the Pro's 18s are normally 36 PSI from what I understand.

I'm running them at 40 PSI now just so the TPMS isn't alarming. Not sure if there's a way to reprogram the TPMS down to 36 psi. The new tires say upto 51 PSI so I'm thinking its ok running 40. Put 100 miles on them already and haven't noticed any discernible difference in road noise or ride quality but it does seem like my mi/kWh has ticked up slightly. Maybe 0.1 or 0.2 but seems like something. Lifting them the 20's felt noticable heavier than the 18s. Should have put the 18's on a scale while I had them off. The 20's inflated weight 72.7lb ea

The overall diameter is smaller. Went from ~33" to ~32" so my speed is indicating faster than I'm actually going. Based on Waze GPS, looks like I'm indicating 2mph faster than I'm actually going. I had 275/60/20s and now I have 275/65/18s. Maybe I should go with a 275/70/18 if there's some EV tire available when its time to get new tires comes.

Aww, yes. Looks like a PRO / Base XLT now

Selling my 20's

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[F150ROD]

Any noticeable change in range or acceleration?

 

[GunRack]

Any noticeable change in range or acceleration?

No difference in acceleration that I've noticed. But still feel like I'm consistently seeing an extra 0.1 - 0.2 miles per kilowatt. I was consistently 1.9 - 2mi/kWh and now I'm 2.1-2.2 indicated. But I don't know if this is due to the inconsistency in speed at all since my speed is now off 2 mph

 

[krusshall]

I went the other way, putting OEM 20” in place of the 18” on my Pro. I don’t have a lot of basis for comparison as I only had the 18’s on for about 400-500 miles but efficiency seems close.

But like you said there is an error now due to the diameter difference and so speedometer, odometer, and efficiency are not accurate. For me, every tire revolution means I’m traveling slightly farther than what the truck thinks. My efficiency should then incrementally bump up by the percent difference of tire circumferences.

I guess I need to bump up my pressure as I’ve got them at 38 psi.

 

[lightspeed]

Aren't many of the forescan codes the same for the Lightning as regular F150s so you can get the TPMS and speedometer recalibrated?

 

[metroshot]

So cool to go from street truck to off road size!

Good idea to keep the 18" the ones Ford speced for best aero performance.

 

[krusshall]

Aren't many of the forescan codes the same for the Lightning as regular F150s so you can get the TPMS and speedometer recalibrated?

That is my hope that the process identified for 2021+ F150 works for the Lightning. I just haven’t gotten around to trying yet.

 

[sotek2345]

I would have went with the 18's if they had been an option for my Lariat, but not worth the expense for me to change them.

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