I'm pretty familiar with my past andcurrent Ram. The tires I replaced were considerably wider and 2" taller then my new tires. There is going to be less resistance to overcome and less mass for the tires themselves. Since the tires are shorter the truck body is now closer to the ground. I recall reading that for every 1" you lower the body you decrease the wind resistance encountered on the front of our "Bricks". My tire pressure is correct per the owners manual. The tire pressure was also correct for my old tires. I'm sure it is a combination of all things that hasgiven memy increase. I've never heard the better mileage in the summer thing before. The temps have not changed much since mid May here though so your statement does not support my increase.

 

dang, longbeds got a 35gallon tank. Thats like 140bucks to fill up

 

Sorry, but I'm confused...you went from a 33 inch tire to a 32.8 inch diameter tire and your mileage jumped 3 mpg? That makes absolutely no sense unless there were other issues such as underinflation or poor alignment, or you changed from a mud tire to a very low rolling resistance highway tire. You musthave meant a 265 size tire?What did you change from and purchase?

I want a set of those tires! I'd glady pay for any set that would make my mileage jump almost 30%. That'd be better that a reflash!

 

Ha, I didn't notice it was a 305 tire. I thought it said 315. Ya, that doesn't make any sense at all unless, like you said, it was a change from a mud terrain tire to a street tire.

 

There's a sweet spot in every motor/drivetrain/body that works best at a given speed.

 

my tank is 26 gallons, i just had a measurement from 30 gallons because i didn't go all the way to empty.

i don't want to run my truck dry and be stranded lol

actually i have a shortbed, but i put 27 gallons in there once and it had gas in it as well. maybe some was in the fuel pump or in the lines, there was probably about 30-32 gallons total spread out everywhere that time.

or i got ****ed at the pump lol.

 

I did switch to a street type tire vs a mud type tire.I drive highway miles so it was a no brainer. That being saidwith the old tires my odometer indicated that I had traveled 238-240 miles round trip. Changing to the smaller tires my odometer now is closer to correct and indicates that I have traveled 270 miles. It is still a bit off as my actual travel is 280 miles. I made anerror in the first postit should have read315s. When the Tire Rack delivered the new tires I rolled them out next to the old ones and there was a considerable size difference. I've included pictures of the old and new tires. Additionally the old tires would rub the stabilizer arms when I tried to make a tight turn. The new tires do not hit any part of the suspension.

 

Well, it probably changed your speedometer back to a closer reading, which will readjusted your odometer and changed how your gas gauge reads. It also your moved rpms up a few hundred, which put your motornearer the spot where your torque curve and horsepower curve meet. While that may have added some mileage, having your vehicles PCM reading an almost stock tire diameter probably made your gauges more accurate.

The stock 265/70 tires your truck came withare just about an inch smaller than a 285/75, and that may depend on brand. AT's usually spec out slightly taller than an M/T

I'd run a couple more tanks of gas throuigh it, and re read your mileage.

 

My truck came with 275/70R17s from the factory so the 285s are not that much larger. I am not using the odometer to figure my mileage. I'm going by known miles traveled 280 (determined independently of my truck) and gallons of fuel used.