Tonelocs47

If your gettin 35"s then get 4.56 ratio, trust me. 4.10 will get you back to normal but the money your gonna spend on it and the fact you want more bottom end power youll def wana get 4.56, it wont kill your mileage either

harding01screw

So not to hijack the thread but with me having an 01 screw with the 5.4. Ive been thinking of upgrading to 33s before this coming winter. Im also considering regearing. I do ALOT of highway driving, minimal towing, and light off roading. Would i want 410s or 456? I know around me its 1500 to get new gears installed just dont wanna have to do it again ever lol

Tonelocs47

If you do alot of highway drivin and want 33s then DEF get 4.10s. 4.10s are usually sufficient until you pass 35", so if you plan to go bigger than that in the future you might wanna consider 4.56s

harding01screw

410s it is then. I have a 9 month old to lug in and out of my truck so i dont wanna go too high and hurt myself lol. 33s and torqing my torsion bars and a couple leafs in the back and ill be good to go.til shes old enough to climb in and out herself.

Travyforyou

DON'T regear for 33"s I have 33.4" (275/70/18) bfg all terrain tires an a 5.4 xlt and it actually gained highway mileage since it made a taller gear causing lower rpms on the freeway! I get like 18-20 mpg highway on mostly flat grounds

Franchi Motorsports

iTrader: (9)

Are you saying you got better gas mileage since you went with a larger heavier tire? Just making sure I'm reading that right. It is late... Lol

Total Automotive Performance

iTrader: (3)

Its partly correct. A taller, not wider (higher rolling resistance) tire could theoretically provide a better cursing RPM. Weight, sidewall stiffness and compound would have an effect as well

3.07 rear gear with 1:1 final drive will need a 28.5" tire to cruise at 2000 rpm.
4.10 rear gear with 1:1 final drive will need a 38" tire to cruise at 2000 rpm.

Now imagine swapping the tires while keep the gears...

Danruff93

Right now I cruse at 2000 rpms at 70 with 285/75/16 and 3.55s

Travyforyou

On an easy take off an a flat rolling freeway, that's exactly what I'm saying. Not all that much weight difference.. Like having a full tanks vs empty or throwing two guys or so n the truck with me won't make a noticeable difference. The taller tire but the same width almost makes taller gears.. To a certain extent it gives better mileage caused by a lower rpm at the same speeds. This heavy of a truck the weight difference isn't a factor. It's what I HAVE noticed, not a guess. But once I get on the gas the initial take off speed is slower since the gear ratio has slightly changed.

MyFX4Project

This guys right. It really sounds weird that you gained mpgs with a bigger tire but the mathematics that were shown make it make sense. My rpms are around 2000 at 62mph with 315/70/17 and 4.56s. Before I regeared I got better highway mileage... now my hwy/city is about the same maybe 1-2 difference.