EPA MPG vs real world MPG clarified
#121
I get worse mileage in MN than I do after I fill up in another state. The 10% ethanol mandated by law in MN really does have a negative effect. It's not unnoticeable like the bureaucrats who mandated it said it would be. I know it should be marginal, but its noticeable.
Last edited by Grouseguy; 02-07-2014 at 02:36 PM.
#122
if the different size tires raise the vehicle slightly it will effect mileage. also bigger tires in a city environment will drop mileage. I run lifted trucks for work and my trucks get 7 mpg in the city. I run metric tires that are over 33" when well used and measured when they are mounted on the vehicle under the vehicles weight. which is not how the tire companies measure tires. 3.73 isn't a real low gear anyway if you had lower in both truck the difference would be much less between the two, even though it would be lower overall. thisis if the tires are different in diameter/circumference. sometimes lower gear doesn't make mileage worst but that isn't the case 98% of the time. I have talked to guys with the new 6.4 in the ram and the 4.10 gears seem to net them the same if not better mileage by a small margin. when I was looking at ram trucks to buy the tire size from 17" to the 20" was about a inch and a half. that means the truck can be almost 1 inch taller so it pushes more wind, taller tires are harder to turn from a stop.
#123
Senior Member
if the different size tires raise the vehicle slightly it will effect mileage. also bigger tires in a city environment will drop mileage. I run lifted trucks for work and my trucks get 7 mpg in the city. I run metric tires that are over 33" when well used and measured when they are mounted on the vehicle under the vehicles weight. which is not how the tire companies measure tires. 3.73 isn't a real low gear anyway if you had lower in both truck the difference would be much less between the two, even though it would be lower overall. this is if the tires are different in diameter/circumference. sometimes lower gear doesn't make mileage worst but that isn't the case 98% of the time. I have talked to guys with the new 6.4 in the ram and the 4.10 gears seem to net them the same if not better mileage by a small margin. when I was looking at ram trucks to buy the tire size from 17" to the 20" was about a inch and a half. that means the truck can be almost 1 inch taller so it pushes more wind, taller tires are harder to turn from a stop.
#125
Senior Member
Are you going to use smaller skinnier tires to lower it, they have less rolling resistance and drag so that way there might be a infinitesimal MPG gain. Of course it would look odd and reduce the weight carrying capability and likely make a harsher ride and handling would be who knows where.
The only reason to do it with lower springs is because you like the look. You are messing with the suspension geometry though.
How much would you have to save to cover the cost?
I'm just guessing, doesn't mean I'm correct.
The only reason to do it with lower springs is because you like the look. You are messing with the suspension geometry though.
How much would you have to save to cover the cost?
I'm just guessing, doesn't mean I'm correct.
#126
Well that's what my wife says…."you're going to take a suspension created by a team of engineers and mess it all up" so I hear you there. Maybe finding the lowest rolling resistance tires of the same size would be best when my stock tires wear out. My truck is a grocery getter so capacity doesn't matter but skinny tires would like kinda weird.
#127
Senior Member
I get worse mileage in MN than I do after I fill up in another state. The 10% ethanol mandated by law in MN really does have a negative effect. It's not unnoticeable like the bureaucrats who mandated it said it would be. I know it should be marginal, but its noticeable.
The Ethanol is Only good for the farmers not the vehicle. :-)
#128
Senior Member
Well that's what my wife says…."you're going to take a suspension created by a team of engineers and mess it all up" so I hear you there. Maybe finding the lowest rolling resistance tires of the same size would be best when my stock tires wear out. My truck is a grocery getter so capacity doesn't matter but skinny tires would like kinda weird.
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Fastskiguy (03-03-2014)
#129
67,000 miles never been to the shop except for oil changes
Most trips I average 21 to 22 mpg. 1 trip of a 1,000 miles (Wichita ks to Atlanta Ga) 23.8 mpg.
Trip from Wichita, Ks to Detroit, Mi 23.8 mpg
3.15 gear ratio with Hankook P235-75r17 nitrogen filled tires.
A friend bought new rims and tires for his 4X4 SCB XLT so since my tires had 65,000 and look like I could get another 10 out them I decided to buy his rims and tires.
P275-65r18 no nitrogen
Now my gas mileage sucks....... Can't get 20 mpg Where I constantly got 21 to 22 now I am lucky to get 18. Pulling my 4,000 lb trailer where I use to get 16 to 18 depending on wind now is 13 to 15 mpg.
So here is the question? Was it the nitrogen in the tires that gave me the good mpg?
The tires now altho are taller should have just changed the speedometer making it slower. It is slower by 3 mph now.
I am thinking it is the width of the tire. These tires are a lot wider. More rubber on the pavement more wind drag.
Most trips I average 21 to 22 mpg. 1 trip of a 1,000 miles (Wichita ks to Atlanta Ga) 23.8 mpg.
Trip from Wichita, Ks to Detroit, Mi 23.8 mpg
3.15 gear ratio with Hankook P235-75r17 nitrogen filled tires.
A friend bought new rims and tires for his 4X4 SCB XLT so since my tires had 65,000 and look like I could get another 10 out them I decided to buy his rims and tires.
P275-65r18 no nitrogen
Now my gas mileage sucks....... Can't get 20 mpg Where I constantly got 21 to 22 now I am lucky to get 18. Pulling my 4,000 lb trailer where I use to get 16 to 18 depending on wind now is 13 to 15 mpg.
So here is the question? Was it the nitrogen in the tires that gave me the good mpg?
The tires now altho are taller should have just changed the speedometer making it slower. It is slower by 3 mph now.
I am thinking it is the width of the tire. These tires are a lot wider. More rubber on the pavement more wind drag.
#130
Senior Member
Just starting here...If your tires are taller, they are bigger around. one rotation = a few more inches in distance traveled. Our odometers don't know we have bigger tires, they record fewer revolutions of the tires, driveshaft, tranny. I learned that one with low profile tires on a Vdub. Check your odometer against mile markers on your next long distance highway trip.
But even with the computer being off by a little I wasn't getting near the mileage between fill ups with the 18".