The thread is about Duallies but your single wheel probably would be good with 285/75/18. Or 37x11.50x18 Nitto 127 load rated but D which is maybe ok with the lighter gas motor; would need to research it some if you are hauling heavy.

 

I have a dually also, got carried away

 

do yoi have spacers in rear

 

old thread but heres some comment's

2019 f-450

37 on 22.5's fit and are fine if you only drive on level ground and always go in a straight line and dont need a spare.

had rubbing on turns mainly at anti sway bar and I installed a helwig f-350 bar which has a different shape to fix that.

then had rubbing on driveway exit dips and as I adjust speed to speed bumps....so no choice but to do a lift....did 4 in the front and 4 at the rear and maybe could have gotten away with 2 in the front and 2 in the rear but shock sizing was a problem at 2 in the front and 2 in the rr ear so went with 4 and 4 and shocks for that size were no problem.

drag bar drop bracket, radious arm drop bracket, pitman arm drop, sway bar new links, new shocks and brake hose brackets were all done.

BUT....had I known...I would have got 35's only due to storing a spare...I have a spare 37 but even deflated it will not mount in the spare storage position. 35's would go there no problem. there seems to be some success storing 37's if you dont have a 3" reciever .....so the 11 thru 16 SRW guys. 2017 thru 2019 DRW guys all have 3' recievers. dont know about 20+ . only solution to store a 37" spare is to change the hitch at a cost of about 4K. there are aftermarket hitches that can sotre up to a 40' tire inflated. only draw back is the weight rating of the aftermarkets.....they seem to stop testing at 15K and will say the hitch can probally do more....wish they would test to 20K. my 2019 3" hitch is rated at 20K and while I will probally never use that rating...there is some comfort in my mind of using the highest rated hitch the truck can mount.

so yes....35's would be my recommendation


as far as kits go...lately more and more complete kits are avail and thats the route I would go....I would stay away from piece meal kits sourcing partss from different brands and places. always go with welded plate rear blocks and go with new front coils vs spacers.

I had a few do overs with parts...the rear blocks got pin hole elongation so those were redone . the pitman arm drop was a pia due to the arm that the book calls for did not work becuase ford decided that the advanced steering features for a 2019 could be satisfied using SRW steering box and shafts so we got jipped on that component and had to buy a drop bracket for an SRW.....and later if I have to replace my steering box...its going to be spooky bananas trying to figure out which box.

dual steering stabilizers a must...tried the mounts that use 2 bolts on the front gear box but those two bolts kept sptipping and after heli coiling them twice decided to get a dual steering stabilicer center mount that does not use the two gear box bolts....stryker off road has one that center mounts with bolts to the axle only and does not use grearbox bolts.

I had to buy a long socket and a super large torque wrench for the ubolts. I changed the nuts on the ubolts from the lug nut style nuts to coupling nuts which are about 2X to 3X in length compared to regular ubolt nuts.

there are rear blocks that have loops that the ubolts go thru....I dont think those have any usefull function and are a PIA to thread the ubolts thru.

when you get done...check your aft rim to forward rim distance on both sides...a 1/8 to 3/16 differenc ein lenght will cause your steering to pull in one direction or another....to adjust the length cargo straps to tow hitch on the short side until you get the distance corrrect then toruque down the u bolts.

due to the extra strain on steering box...I installed a in line transmission filter on the power steering return line and change it ever 5K miles or so,

 

Fuel Mileage? On a dually with 37" tires? LMAO! Boulevard cruiser alert! 😄 What are you towing?

Changing from a 33" diameter tire to a 37" diameter tire effectively changes your axle ratio numerically lower (taller). Your powertrain works harder to pull the same load. You likely won't notice much difference until you recalibrate your speedometer so that your distance traveled is correct.

Please don't tell me that you bought a Superduty Dually for the fuel economy, lol. My SRW 6.7L dropped about 2mpg going to 37" tires. My brain handles the 5mph recalculation on the fly.

 

Doesnt mean you cant try to get mpg, in anything you drive, everywhere you read, about a new tune for SuperDuty's it pulls better, shifts better, and gets better milage, so why not want more, my King Ranch had 35's, 16mpg back and forth to work, now with 37's its 13mpg, so it hurt, now I dont let it sit and idle as much, or remote start before work any more to help consumption of fuel, gas or diesel prices not coming back down, so anything helps...no matter how small or Insignificant, people think it is.