When I look at Ford’s towing guide for the 2018 F-150 SuperCrew 145” wheelbase 4WD with the 3.5L eco boost twin turbo and 3.55 gear ratio, there are three options:GCWR of 16,100# = 10,700GCWR of 16,700# = 11,000 (Limited package only& max tow package)GCWR of 18,100# = 12,700 (requires 20” wheels & max tow package)A) is the GCWR figure available somewhere that I am not finding or is it a calculation that I need to do?B) is it really just by jumping to the 20” wheels adds a hypothetical 2,000# in tow capability? There has to be more to it than that. If not, how is that possible?No, I’m not anywhere close to that. 10,700# would handle our trailer just fine. But to me, additional cushion is always better.

I wouldn’t buy an F150 without their max tow package...and I’d opt for the 12700.

I've got the older Ecoboost F150 (2013) and it has the 20" wheels and max tow package. But, they are different for your era of Ecoboost..I'm not really sure what the 20" wheel package does? Even the P OEM tires exceeded the rear axle rating of #4050. I did get some "XL" rated 20" tires for it and that even exceeds it even more.. I'm towing a #7000 GVWR TT and that's about all I want to tow with my F150 and still have a comfortable tow.. Sure, it has all the power you can need/use... But, it's still just a light duty truck, no matter what that 'max tow' means...Good luck! Mitch

Nothing meaningful if drivetrain is the same, IMO.That's why it's futile to live and die by the "ratings."

Ford doesn't specifically tell us why 20" wheels have a higher tow rating but we do know that part of industry testing procedure is stability. So the best guess that I have is that the larger wheels are stiffer and therefore more stable.The interesting thing is that the F250 comes with 18" wheels and the exact same size tires as they put on the F150 but has a much higher tow rating. The F250 tires are LRE whereas the F150 comes with either P series or LRC tires. Maybe the extra 4 ply rating is enough to justify the difference. But we will probably never know for sure.

Two tires from the same manufacturer, same style, same tire line, same load range, with one 18” and the other 20”, the 20” will have a higher load rating than the 18”. But not that much difference. Maybe next higher load range tire on that package? Or some slight difference in suspension? Don’t know.

F-150 20” wheels | Good Sam Community

Lwiddis
Explorer II
Oct 28, 2020
I wouldn’t buy an F150 without their max tow package...and I’d opt for the 12700.
MitchF150
Explorer III
Oct 28, 2020
I've got the older Ecoboost F150 (2013) and it has the 20" wheels and max tow package. But, they are different for your era of Ecoboost..

I'm not really sure what the 20" wheel package does? Even the P OEM tires exceeded the rear axle rating of #4050. I did get some "XL" rated 20" tires for it and that even exceeds it even more..

I'm towing a #7000 GVWR TT and that's about all I want to tow with my F150 and still have a comfortable tow.. Sure, it has all the power you can need/use... But, it's still just a light duty truck, no matter what that 'max tow' means...

Good luck! Mitch
Grit_dog
Navigator
Oct 28, 2020
Nothing meaningful if drivetrain is the same, IMO.
That's why it's futile to live and die by the "ratings."
Groover
Explorer II
Oct 28, 2020
Ford doesn't specifically tell us why 20" wheels have a higher tow rating but we do know that part of industry testing procedure is stability. So the best guess that I have is that the larger wheels are stiffer and therefore more stable.

The interesting thing is that the F250 comes with 18" wheels and the exact same size tires as they put on the F150 but has a much higher tow rating. The F250 tires are LRE whereas the F150 comes with either P series or LRC tires.

Maybe the extra 4 ply rating is enough to justify the difference. But we will probably never know for sure.
BB_TX
Nomad
Oct 29, 2020
Two tires from the same manufacturer, same style, same tire line, same load range, with one 18” and the other 20”, the 20” will have a higher load rating than the 18”. But not that much difference. Maybe next higher load range tire on that package? Or some slight difference in suspension? Don’t know.
philh
Explorer II
Oct 29, 2020
Groover wrote:
The F250 tires are LRE whereas the F150 comes with either P series or LRC tires.

Maybe the extra 4 ply rating is enough to justify the difference. But we will probably never know for sure.

I went from P to 10ply tires on my F150. It was a HUGE difference. I don't even bother tightening sway on the WD hitch. Semi's passing me would cause a little wiggle as the front of the semi was even with the hitch. No longer feel that wiggle.
JIMNLIN
Explorer III
Oct 29, 2020
Ford can assign any numbers they want for a GCWR/GVWR/GAWRs. GCWR numbers aren't required to be placarded on LDTs at this time.
Ford markets around 11 different GVWR packages and 5 GAWR packages on the F150 trucks. You would have to chase down all the mechanical specs (std and optional equipment) on the three tow rating you show. That should give you a better idea of the differences... if any. fleet ford clicky
mkirsch
Nomad II
Oct 29, 2020
It would be easy to determine by going to a lot and looking, that the load rating of the 20" tires is higher than that of the 16"/17"/18" options.
StirCrazy
Moderator
Oct 29, 2020
the 20" tires handle more weight, to get the 11500lb payload in my f350 you needed the 20" wheels.

Steve
Grit_dog
Navigator
Oct 29, 2020
These last 2 posts are false, OP.
It’s not the tires and wheels increasing the capacity unless Ford “chose” to add higher rated tires to the 20s.
Actually in general if the tire OD is the same (unless the 20s are notably taller), the greater the rim diameter, the lesser the sidewall height and the lower the load rating.
And besides people are confusing gvwr, aka payload, with tow rating that is increasing the gcvwr considerably without a large or any payload increase.
My “guess” is the 2klb tow increase is from lower gearing and may have mis-read or it misprinted.

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