So I swapped out my BFGs for Toyo Open Country ATs. They are the same size but the Toyos are 9lbs heavier. Would my HWY MPG drop 3-4?? Seems a little extreme. Anyone else notice this at all?

cheers,

 

thats very extreme in my opinion. only thing i can think of is air pressure possibly.

 

Are the tires the same size. I know when I went to 35's my mpg went from 12 to about 9 haha. I would also check the tire pressure

 

I have had Toyo Open Country ATs on several trucks and never had any mpg issues. In fact, I plan to buy them next time I need tires. My guess would be too low pressure or bad alignment or some other issue. At 9 pounds extra weight per tire, that is only 36 pounds overall. I put 180 pounds of sand in the bed for winter/snow driving and don't notice much of a decrease in mpg...gotta be something else besides the tires...let us know what you find

 

Were the BFGs bald? If you take the tread off of one tire and slap on a new set the difference would probably be more like 15 pounds each. But like davzog said, that weight really isn't much compared to a 5000+ pound truck.

Also if they were bald, you were rolling on tires with a one inch less diameter(since the tread usually looks around a half inch). You have a change in the odometer reading when you change the actual diameter.

Plenty of factors along with improper balance, air pressure, misalignment, etc.

Did you correct the odometer with a programmer or other similar device? If not then that drop is also from the computer miscalculating.

 

Yes I did do it with a programmer...

 

My old tires still had meat left on them. I got rid of them because they are crap in the snow, and I got a wicked deal on the new ones. Ill check the pressure and see. thanks everyone.

 

Snow? In Calgary? Nah ...

Up here in Edmonton, they're just clearing the snow off the roads ... now that it's starting to melt and the weather has done the hard work for them. What mileage are you getting?

 

HAHA ya our chinooks take care of most of the snow.

on the highway I would get 18-20 (according to my Gryphon) now Im getting 13-15.

 

Same here i droped about 2-3mpg as well cant figure out what the problem is

 

That's 9 more pounds per tire X 4 = 36 pounds more to move from dead stop up to speed just like the rest of the truck ...
... PLUS you have to spin those tires up to speed like the 4 heavier flywheels that they are acting like. You'll also pay a penalty in slowing / stopping / ride / steering though you may not always notice it so much.

There's also the more agressive tread that may well offer greater rolling resistance.

Yeah, could be the cause of dropping fuel mileage IMHO.

 

tbear you are spot on. It isn't the extra weight you are weighing it is the extra weight you have to get rolling. Also used tires tend to deliver better fuel mileage. The heat cycles, harden the rubber a bit and there is less tread so less friction.

 

Ya I guess I never thought of that. The tread is a lot more aggressive than my old BFGs. What kind of air pressure should I run them at? I think there is 30 psi in there now, should i bump it to 40?

thanks again everyone.

 

I was looking at the specs of the stock BFG in 275-65/18 and Toyo's AT in the same size. The "P" metric tires weight roughly the same, actually Toyo is a lb. less. On the other hand, the "LT" metrics are 8 lbs. heavier. You might want to read this about inflation pressures and LT tires.

 

Holy crap, I cant believe hot much warmer that tire got when underinflated.