Bear in mind a tire that is advertised as any diameter, is an inflated tire off the truck and not a relevant measurement to determine engine rpm. The weight of the truck will reduce the diameter under the load of the truck. When looking at any gearing chart, use a diameter that is an 1" below the advertised diameter for that reason. Same applies to your stock tires, if you want to keep it in the same range.

 

Good post Windsor, Didnt think of that I will go for a 4:27:1 gear set. Thanks!

 

The thing with gearing you should look at is total circumference. The exact revolutions per mile, not standing height. The gear ratio is: the amount of times the driveshaft revolves per the amount of times the tire makes one revolution. I.E. the driveshaft revolves 4.27 times per the tire 1 time total revolution =4.27:1 gear ratio. ( to test what you have, mark the tire at the outside edge of the sidewall, move it one total revolution and count the times the driveshaft has revolved.)

The tire will bare weight and might flex but doesnt shrink the tire size. And yes, your diameter from ground to top of tire will differ when weight is on it but doesnt affect the amount of times your tires make a revolution.

If you want to question it, measure the tire all the way around the tread on and off the truck and you will get the same circumference. Did i confuse anyone yet?

Hope that helps.

 

when i first bought my truck (2006 4x4) i was working in a machine shop and i built my "3 inch" leveling kit. it was a true 3" block that bolted to the top of the coilover. after installing, the coilover rubbed the upper a-arm from where the spacer added that much lift. just be careful- i had to make a 2" block which worked out much better. be sure that the 3" leveling kit you are looking at lifts the trruck 3" and not that the block is 3".

also- with just 2" blocks in the front and none in back, the front sits just a bit higher than the back.

imo- 3.73:1 with 33" tires. still have good milage but better takeoff and you will be "fooling" your truck to think it still has factory tires. i am currrenty running the stock 3.55s and shift points are off- power is still good though. my plans are 3.73 soon with locker in rear and limited slip front.
cheaper fix- programmer