4.30 will put u slightly under stock tires and 3.73. 4.56 will put u slightly over. I run 4.56 and I am very happy. Lots of power on takeoff and runs 80 easilly on the hwy.
Sent from my portable forum surfing device.
Actually the reason I was even considering 4.56 gears was because the guy that did some body repairs on my truck has 38's on his truck and he was saying he liked the setup and it put him pretty much right back at stock rpm.
Just doing a comparison between Toyo M/T's, the 37's should run about 68 mph with 4.56 and the 38's, actual size is 37.7, should run 69 mph at 2000 rpm.
The same setup with 4.30 gears, using a mph calculator from angelfire.com.
37" tires should run about 72 mph and the 38's 73 mph.
Just to complicate things a little more
using the same calculator, 40" tires at 2000 rpm with 4.30 gears should run about 78 mph and with 4.56 gears it comes out to 74 mph.
But the reason I started this thread was to get as much info from you guys, from your real experiences after you modded your trucks and not exactly from some rpm and mph calculator. I guess with the calculator it will get us close to our goals but ultimately it boils down to what we are willing to sacrifice regarding mph vs rpm.
But lets here a few more testimonials with your current or previous setups, hopefully this thread will help other people decide which gears they should choose after they they lift their truck up and put bigger tires on. I will try to insert the link from where I was getting all the data for mph and rpm calculations. MPH Calculator Woody's Fairlane Site
Thanks every body I appreciate everyones help.
E99 F-250 SCLWB Lariat, Born 10/98
7.5" Skyjacker/Icon lift, 37/13.50 20 Toyo M/T's on KMC Rockstars, Bushwacker flares, 03+ lighted towing mirrors, smoked tail lights, new OEM 4" chrome nerf bars, Banks 4" TBE, Superchips tuner, K&N