Adobe2X

We went to look at a 2012 Max Tow EB Lariat SCREW with the short box.....drove it too...was not that impressed with the power, but it was a short drive and I did not really hammer it....The thing that surprised me was the door sticker for the 2012 had a max capacity of 1628 pounds. My 2010 5.4 Max Tow SCREW with the long bed (which I would have thought weighed more) has a door sticker of 1754.
I have the 18 inch wheels and the 2012 had the 20's with the Pirelli tires. Why would a truck that weighs less than mine not be able to carry as much?? The short bed should weigh less than the long bed, but do the 20 inch wheels weigh THAT much more than the 18's, or is it more related to the sidewall on the tires?

sllydderrr

Assuming the same GVWR, the more options you pile on the less payload you'll have available for carrying things. My 2011 XLT SCrew has a payload of 1848 lb. Typically a Lariat or Platinum will be a couple hundred pounds less because of the sunroof, extra power equipment, etc.
20's are usually heavier than 18's assuming the same overall tire diameter so that will reduce the carrying capacity.

EDIT: I didn't read the question carefully enough
I had 20's with Pirelli tires on my truck for a short while. The load carrying capacity on those was less than the 18" Goodyear's that came on the truck. The load capacity of the Pirelli's was still higher than the payload capacity of my truck so I don't think that is the issue.

superthornbird

The tires. The shorter sidewalls plus they are "p" tires which has a significantly smaller load rating than that of a "lt"tire

kozal01

iTrader: (2)

This ^^

sllydderrr

FWIW, my 2011 Max Tow truck with 1848 lb payload came with P rated tires.

SultanGris

I think this is your answer, while the other guys are correct that the 20s have a lower rating than 18 LT tires the 20" tires rating is higher than the trucks rating so therefore its obviously not the tires limiting the number.

f6bits

My SR-As are P metric 18” tires. Their load rating is 2600 lbs each. My rear axle GAWR is 4000, so there’s more than a thousand lbs until I max out the tires. I’m still not exactly sure why my payload capacity is 1300 lbs. Maybe the 36 gallon fuel tank has something to do with that, but still, the tires aren’t my weak link and I wish I knew what was.

In the case of 20” tires, they definitely have a lower load rating than an equivalent 18” tire. The Scorpion ATR 275/55R20 is rated at 2400 lbs. Only a 200 lb. per tire decrease.

HCFX2013

sllydderrr

@Hardcore ^this!

Adobe2X

I am the OP on this, and maybe the extra equipment on the Lariat (sunroof, 20 inch wheels, leather etc.) would account for the difference in carrying capacity....120 pounds can add up fast....but I also would have thought that the shorter wheelbase would weigh a bit less too.....it just surprised me I guess.