I want to run 35 inch or 37 inch tires on my 01 screw 4x4 with 5.4 what gears should I go with a posi rear end. I'm running 285 70 17 tires on 17x9 wheels with no apparent problems now

 

what kind of driving do you do?...highway or city?....id prolly go with 4.88's....especially if your going thirty sevens and you do mostly city

 

4.56's if you plan on staying with 35's. 4.88's if you plan on running 37's someday.

 

I love in the country drive about 40 miles to work and I tow a four wheeler and pontoon alot. I hunt so I do some off roading. Will the 4.88 be to much when I go on the interstate at 75 on trips about once or twice a month?

 

Live in the country. But I love it too lol. iPhone has its on spelling demon

 

4.88s and interstate driving at 75 are gonna keep u at about 2300-2400 rpm. I have 4.56 and 35s and I'm at 2000 rpm at 65. I don't usually drive faster than that just to help save some gas.

 

Cool thanks

 

I have a f-150 4.6 V8 XLT, Flat lift with 35's on it. Noticing the speedometer about 5 mph more since I have put the 35's on. Should I upgrade the rear differential? If so what to? And do I have to adjust the front too? Gas mileage is not as good, take off speed is a little bit slower. Local shop says about 1800 to do it. Should I? Or will it be fine. I don't haul often and off road sometimes. CW

 

Your speedo should be reading lower with the bigger tires. And I'd do 4.56's with 35's. If you plan on using 4x4 then you need to do the front too.

 

i turn 2K rpms at 60mph when driving with my 4.88's and 35's