Regearing equation

[2TimingTom]

I am very strongly considering regearing my Explorer to make it a better tow vehicle now AND when I increase the tire size.

I found an equation that helps:

New tire diameter (in.)
------------------------ x current axle ratio (:1) = new axle ratio (:1)
Old tire diameter (in.)

Because I is smart at math, I decided to use 4.10 for my current axle ratio (because 4.10 is a better starting point for towing even though mine is 3.55), plug in 4.56 for the new axle ratio and use 28.9 for the old tire diameter (grabbed that number off tirerack for a stock size tire) and solved for the new tire diameter.

I got 32.14".

So basically that means that if I have 32" tires and 4.56 gears, it will perform the same as a truck with stock tires and 4.10 gears.

Now the question: a stock Explorer with 4.10s, was it a good tow vehicle? I know it was the most aggressive you could get from the factory, but was it good? Should I stop at 4.56 or should I crank it up another notch to 4.88 for more of a performance tow? I tow a medium sized popup camper through the mountains of CO.

Any guesses as to what 4.56s and 32s would do to fuel economy? 4.88s and 32s?

[IZwack]

"was it a good tow vehicle" -- that question will vary from driver to driver and from load to load.

But IMO, if you are going to tow something serious on a regular basis or long distances, get a beat up old truck, preferably 3/4 ton and up. But if you are stuck with an Explorer and if you are going to tow with it, don't increase the tire diameter because this just decreases the stability of the vehicle and the load, increases the stresses on the hitch if you use longer and longer "drop" hitch balls, decreases MPGs, and so on and so forth. Rather than spending the money on larger diameter tires, get the same diameter tires that are better suited for towing (better load range) which will slightly increase stability (since such tires often have more plys) and tire longevity when the vehicle is under load.

[2TimingTom]

Well, I went ahead with the 4.56 gears. The speedometer is off by 25% now, but it gets moving very quickly now. The throttle is very sensitive now as well.

I'm not at all concerned with fuel mileage because I rarely drive it. Out of the 30 days in a month, it gets driven maybe 4 of them.

I understand your concerns about going with bigger tires, but I'm still looking into it. My Explorer is also my 4wheeler. I'm on the look out for some 32's with at least a C load range. And I don't think the amount of which I tow (weight wise) will overstress a drop hitch. And I may go with new wheels that increase the track, making it more stable.

[Wills05xlt4x4]

Any update on mpg? How's it doing two months later? Tow good?
I've got the tires and gears Will be in the truck very soon!

[2TimingTom]

Without a trailer, it accelerates great. Speeds above 70 mph on the highway seem to be out of the sweet spot of the motor so I stay in the 65-70 range.

Towing with a trailer is now so much better. I swear it accelerates as well now with a trailer as it did before without a trailer. It really is that good. Unfortunately, with the state on fire much of the summer, we haven't done much camping but we did get one trip in and I had no problems maintaining or exceeding the speed limit while going up some of the steep inclines. I've towed this same route without gears and I really had to work it to maintain the speed limit- and would usually fall behind.

MPG wise it's been great. I don't have any just normal driving miles on a tank yet. First tank while towing was 18 mpg. And a couple of tanks while 4wheeling gave me 16 mpg. Not bad considering without gears I'd get 16 mpg in normal driving.

Absolutely glad I did them.

[jd4242]

Never fear the gear!! best mod you can do to a truck and always go big!what size tire are you running with the 4.56?

[bronchole]

For thoes wanting to do gearing change calculations I sugest using this site:

http://grimmjeeper.com/

It may not have the exact transfer cases we use here so you need to know your low range ratio if you are looking for crawl ratios. Otherwise it is an awsome tool.

Dan

[snoranger]

Originally Posted by bronchole

For thoes wanting to do gearing change calculations I sugest using this site:

http://grimmjeeper.com/

It may not have the exact transfer cases we use here so you need to know your low range ratio if you are looking for crawl ratios. Otherwise it is an awsome tool.

Dan

Use the BW1354 in place of the 4405. They are the same ratio. (actually the low range gears are interchangeable between the 2.)

[2TimingTom]

Originally Posted by jd4242

Never fear the gear!! best mod you can do to a truck and always go big!what size tire are you running with the 4.56?

30" BFG A/Ts.

I just installed a 2" body lift and plan on doing something to the rear springs to get more lift (either shackles or re-arch) and TT up front to clear 32" or 33" tires.

[jd4242]

Originally Posted by 2TimingTom

30" BFG A/Ts.

I just installed a 2" body lift and plan on doing something to the rear springs to get more lift (either shackles or re-arch) and TT up front to clear 32" or 33" tires.

O wow.i bet you do have plenty of power!

[Kevin-Truro,NS]

Ever consider doing an over/under swap to your rear axle?