I'm looking at putting 31's on my truck. Its a daily driver that see's mud during the late summer and all thru hunting season.

How bad will this affect my gas mileage? Will this wear on my tranny and engine faster? You know, all the normal questions? Does is even make sense or should I stay where I am?

 

well i have not noticed any drop in gas mileage with my 31's... they are awesome for off road since they are wider and grip better than the stockers i had... overall it was a great mod

 

Larger tires = greater circumference = more distance covered per revolution. This means for the same given speed your engine, transmission, and entire drive-line will be turning slower. This could mean for better gas mileage at speed, as you are rolling at a lower RPM, but it will be offset by the need for additional torque. The larger the tires the more torque it will take to turn the wheels and drive the vehicle. This will make your truck feel slower off the line as you won't have enough power to turn the larger radius as quickly. This will probably cause you to stomp on the gas to get up to speed and therefore hurt your economy.

Economy will also be impacted by the added weight of the larger (and heavier) tires, especially if you go for a width increase as well.

Exactly how it will effect you will depend on what you are running now, how your truck is geared, and how you drive. If you never ever jack-rabbit off the line then the impact will be less than it would be for someone who frequently does launch rather agressively.

31" tires are probably a safe bet for most Ranger applications. For what it's worth, that's the maximum size tire Ford has the Ranger officially certified for. Meaning the computer is programmed to accept gear ratios and tires sizes up to 4.10 and 31" respectively. Anything beyond that and you'll either be limited to after market correction methods or left w/ an innacurate speedo/odo..

 

what size is the stock tires? i know on sarahs ranger the p245/75/16s are so close to a 31 that it would have no direct effect on the truck. dont forget most 31s arent really the size they claim. i wouldnt worry about it to much.

 

I would say for the lift you have go no smaller then a 32 but thats me...