I HAVE A 2002 5.4L, 4 X 4 SUPERCREW WITH 305/17 MTRs. THE FACTORY GEARS ARE 3.55. I HAVE JUST INSTALLED A K & N FIPK, SUPERCHIP & GIBSON CAT BACK EXHAUST SYSTEM. I WAS LOOKING AT CHANGING THE GEARS TO 3.73 OR EVEN 4.11. TRUCK STILL SEEMS A LITTLE SLUGGISH ON LOW END. LOOKING FOR A LITTLE MORE RESPONSE ON THE LOW END, BUT DON'T WANT TO SACRIFICE PERFORMANCE ON ROAD TRIPS.
CAN ANYONE OUT THERE GIVE ME AN IDEA ON CALCULATING THE RPMs AT DIFFERENT SPEEDS, OR ANY PROS / CONS ON WHAT I AM TRYING TO ACHIEVE.
THANKS IN ADVANCE!

 

http://www.ring-pinion.com/calculators.shtml

 

THANKS, I FOUND THE INFORMATION I WAS LOOKING FOR. I HAVE THE FORMULA BELOW IF ANYONE OUT THERE NEEDS IT.
(AXLE )(TRANS)(T-CASE)(MPH)(336)/=RPM
(TIRE DIA.)

 

Here it is: https://www.f150online.com/forums/sh...threadid=95307

 

with that size tire you should be deff running 4.10's if you want some low end power, i was thinking about getting 33's and a lift and if I do im def getting 4.10's.