im prolee gonna be gettin 35s or 36s and im gonna regear when i get em, is 4.10s right or something like that, and how much would it cost for gears and labor and how much would it cost for just the gears.please help, any input is appreciated. thanks.

 

How about some info on your truck What year, model, and trans? The gear ratio of the trans will greatly affect what gears you need for the rear end. Also what kind of driving is the truck used for because the gear ratio you choose can affect your gas milage and drivability. Search online for gear ratio calculators, you can type in different tire sizes and gear ratios to see what your engine rpms will be at certain speeds. For a truck that is a daily driver i like to keep my gear ratio kinda high so it will cruise nice on the highway, then i just use 4Lo when i'm doing really serious offroading.

-Jon

 

Might help to know your present gear ratio and whether or not you're happy with it.

 

1995, straight 6, f-150 4x4, manual transmission, mostly gonna be a daily driver back and forth to school. but i want to regear for better gas milage w/ the bigger tires and so it will be easier to turn em in mud.

 

I think 5th gear in the F-150 (mazda) manual trans is an overdrive - .79:1 i think, so 4.10 will work good with a 35 or 36 inch tire. Your gas milage is still gonna suck though.

-Jon

 

Your present gear ratio is... ?

 

need to post your AXLE code from the door jam sticker.

Adrianspeeder

 

yeah, it is overdrive, i dont know what my current gear ratio is. but why will my gas milage suck if i regear, isnt that what regearing is for, so there isnt as much strain on the motor and you will still get ok gas milage???

 

I went from 3:55 to 4:10, after going to 33" tires, and that got me back to stock ratios. My gas mileage didn't change even a little bit (10 mpg downhill, 11 mpg with a tailwind). The truck was much more fun to drive though.

 

If you regear it back to a near stock final drive ratio your gas milage wont go down too much, if you gear it lower than stock for better performance your gas milage will really go down due to the higher engine rpms on the highway. Either way if your going to run something like a 36 x 12.5 mud tire that is a lot of extra weight thats gonna take a little more throttle to get moving. On my 92 i lost about 2 mpg even with a regear (from 12 down to about 10!). Thats just my experiance though, could have been the way i was driving it.

-Jon

 

aight, ima go w/ the 33s 1st and see how it handles em and l8r ill try the 35s and regear it if i have the money. thanks.

 

I just went from 3.55's to 4.10's with 35" rubber. The best thing I ever did to the truck! I tow a 13K 5th wheel trailer on weekends and it works great towing and without. I paid about $1600.00 for the front and rears. But I it is going to pay for it self over the long run, because I can now use reg gas. Before I had to use Premium or it would ping because it was like starting in second gear. At about 65mph I only went from about 2200rpm to 23-2400
without the trailer. Just plain drives better.

 

Sorta. Putting a larger tire on your truck and leaving the gear stock, provided that it isn't too tall a tire will actually increase your mileage. This is because for the same number of axle revolutions you will actually roll farther.

Now as you pointed out, the larger tires put a heavier strain the the engine, this is because it effectively lowers the overall gear ratio. This costs you in acceleration, etc. If you change the rear end gear to compensate you can negate the change and regain your acceleration, at the cost of fuel economy.

Like anything, there is a point of diminishing returns. Put larger tires on it and you'll gain a little bit of mileage. Put too big a tire and the increased rolling resistance will negate the gain. Put gears in it to put more torque to the wheels and you require your engine to put out less power, but it has to spin faster.

What it boils down to is that in a perfect world you can put any size tire on the vehicle you want, as long as you match it with the proper gear ratio, and you haven't lost anything. You also haven't gained anything either except for visual appeal. Being said, unless the factory tire size just bugs you, the cheapest thing to do is put the right size tire on the vehicle and drive it.

 

Agreed. I only changed the tire size on my truck was the fact that I pull my trailer on very soft sand and through pretty tuff dunes and the larger tires give me a bigger foot print and a little more clearence. Drop them down to 15lbs and they just float over the sand, even with 13K worth of trailer behind it.