Tire pressures.

JDubTaco

JDubTaco

Well-Known Member
The door sticker says 29psi cold. I have been running 29psi cold for about 4500 miles. When the tires warm up they are about 32psi. I decided to run a couple more psi the other day on a short 1.5 trip. So, 1.5 hours there I ran 29psi cold / 32psi warm. The 1.5 hours back I ran 31psi cold / 34psi warm. Gas mileage according to the screen on the truck on the way down was around 18-20, but mostly was showing 19. On the way back the screen was showing 22 mostly and I even saw 24 at one point. I would just randomly toggle back and forth to that screen, I didn't watch it the entire time. But I am pretty sure I am getting better gas mileage now. Anyone else done this? Maybe this has already been discussed. I'll report back after more testing. I dont drive it much during the week.
 
I should probably check mine. I lowered them from 36 psi to 32 3 years ago, but haven't checked them since. When they were at 36, the truck felt like it was a ping pong ball going down the road.
 
Yes, a "hard" tire will have less rolling resistance leading to less fuel consumption per mile, ie higher mpg. This is why trains use steel wheels on steel rails, less rolling resistance = bigger loads with less power.

Downsides. Harsher ride, faster tire wear focused on the center of the tire, traction loss from smaller road contact patch.

FWIW, I run 30 psig in my tires (265/65-17) and can get 21-22 mpg feeding a 4.0L at 70 mph.

Consider, these are trucks with a primary purpose of working and hauling loads. If fuel mileage is priority and only hauling people, then a small econo box like a Corolla or Prius is a better choice.

The biggest killers of good fuel mileage are:
Lift
Big Tires
Speed
Gearing
Dead Load
 
Rock62 said:
Yes, a "hard" tire will have less rolling resistance leading to less fuel consumption per mile, ie higher mpg. This is why trains use steel wheels on steel rails, less rolling resistance = bigger loads with less power.

Downsides. Harsher ride, faster tire wear focused on the center of the tire, traction loss from smaller road contact patch.

FWIW, I run 30 psig in my tires (265/65-17) and can get 21-22 mpg feeding a 4.0L at 70 mph.

Consider, these are trucks with a primary purpose of working and hauling loads. If fuel mileage is priority and only hauling people, then a small econo box like a Corolla or Prius is a better choice.

The biggest killers of good fuel mileage are:
Lift
Big Tires
Speed
Gearing
Dead Load
Click to expand...
All correct. I just never seem to get the mileage they state the truck gets, but now it looks like I do with a couple more psi. Probably shouldn't wear the tires any different. And I definitely didn't buy a tacoma for good gas mileage. I bought this truck as my off road beach vehicle mainly. I drive a 2005 scion XB that gets about 33 mpg everyday for work. I did however black out my badges and I definitely increased the horse power!
 
Ahhh......the EPA mileage on the sticker.

Well, that is done on a dynamometer following a prescribed speed chart. The test has never represented common driving. Although, the test is standardized, so all vehicles are comparable to each other within the test parameters.

I've got the increased power combined with the panty dropper on my Sport.......aka hood skewp. Don't do nuthin' but it does give a more commanding appearance.
 
Rock62 said:
Yes, a "hard" tire will have less rolling resistance leading to less fuel consumption per mile, ie higher mpg. This is why trains use steel wheels on steel rails, less rolling resistance = bigger loads with less power.

Downsides. Harsher ride, faster tire wear focused on the center of the tire, traction loss from smaller road contact patch.

FWIW, I run 30 psig in my tires (265/65-17) and can get 21-22 mpg feeding a 4.0L at 70 mph.

Consider, these are trucks with a primary purpose of working and hauling loads. If fuel mileage is priority and only hauling people, then a small econo box like a Corolla or Prius is a better choice.

The biggest killers of good fuel mileage are:
Lift
Big Tires
Speed
Gearing
Dead Load
Click to expand...
And low tire pressure.
I know if I can keep my speeds at 65 mph or less, I can get that sticker advertised mpg. Going over 75 mph all bets are off.
 
I’m trying to find that perfect number. Had my 5000 miles service yesterday and they put the tires at 38psi. As soon as I got home I aired down to 34. 38 definitely rode hard
 
tacojoel said:
And low tire pressure.
I know if I can keep my speeds at 65 mph or less, I can get that sticker advertised mpg. Going over 75 mph all bets are off.
Click to expand...
And WIND
Massive headwind beats me bad all.the.time
Think 30 to 40 constant and I dropped significant mpg at 70 to 80
 
tacojoel said:
And low tire pressure.
I know if I can keep my speeds at 65 mph or less, I can get that sticker advertised mpg. Going over 75 mph all bets are off.
Click to expand...

I'd go nuts driving 65. My normal is around 85 MPH.

I know it can't be accurate, but my trucks mileage thing says I'm getting around 19.2 MPG at 85 MPH.
 
WooD said:
I'd go nuts driving 65. My normal is around 85 MPH.

I know it can't be accurate, but my trucks mileage thing says I'm getting around 19.2 MPG at 85 MPH.
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If you haven't changed to larger diameter tires, your speedo should be spot on. I wouldn't rely heavily on what the dash gauge claims for mpg., You have to do the actual math.
I travel mostly secondary highways here where the speed limit might be posted at 55 mph tops. I have driven on our interstate highways too. CRAZY! Seems 85-90 mph is pretty common among many drivers now, yet roads are posted at 65.
 
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WooD said:
I'd go nuts driving 65. My normal is around 85 MPH.

I know it can't be accurate, but my trucks mileage thing says I'm getting around 19.2 MPG at 85 MPH.
Click to expand...
Highly skeptical. Perhaps on a downgrade with a tail wind looking at an instantaneous dashboard reading. We have an '02 Chevy Trailblazer with the 4.3L inliine 6 that is capable of 99 mpg according to the instant fuel econ dashboard reading..........pulling a folding camper descending long grades out of mountains. Climbing into the mountains that 99 mpg was offset by the 10 mpg pulling the same camper on the same trip.

At 85 mph a stock truck will be below 15 mpg. They aren't geared for economy and are bricks aerodynamically. Modifications normally reduce fuel economy. Every doubling of speed increases aerodynamic drag by a factor of 4. So, at 85 mph you have 4 times the air drag than at 42 mph. Yeah, physics is a bitch.

My truck will lose about 3 mpg doing 75 mph when compared to 65 mph. On a 20 gallon tank that is a loss of 60 miles. Regularly get 20-21 between 65-70 mph. On long trips my interest is range, not speed. The minimal time gained with speed will easily be lost with extra fuel stops, traffic snarls and heavily outweighed with a moving violation.

@WooD you may need to go old school to determine your actual fuel economy. Fill tank, zero the trip odometer, drive for 2-3 hours at 85 mph, fill tank, note the gallons filled and the trip odometer mileage, divide the mileage by the gallons.......... I suspect you'll be surprised and disappointed.
 
Rock62 said:
Highly skeptical. Perhaps on a downgrade with a tail wind looking at an instantaneous dashboard reading. We have an '02 Chevy Trailblazer with the 4.3L inliine 6 that is capable of 99 mpg according to the instant fuel econ dashboard reading..........pulling a folding camper descending long grades out of mountains. Climbing into the mountains that 99 mpg was offset by the 10 mpg pulling the same camper on the same trip.

At 85 mph a stock truck will be below 15 mpg. They aren't geared for economy and are bricks aerodynamically. Modifications normally reduce fuel economy. Every doubling of speed increases aerodynamic drag by a factor of 4. So, at 85 mph you have 4 times the air drag than at 42 mph. Yeah, physics is a bitch.

My truck will lose about 3 mpg doing 75 mph when compared to 65 mph. On a 20 gallon tank that is a loss of 60 miles. Regularly get 20-21 between 65-70 mph. On long trips my interest is range, not speed. The minimal time gained with speed will easily be lost with extra fuel stops, traffic snarls and heavily outweighed with a moving violation.

@WooD you may need to go old school to determine your actual fuel economy. Fill tank, zero the trip odometer, drive for 2-3 hours at 85 mph, fill tank, note the gallons filled and the trip odometer mileage, divide the mileage by the gallons.......... I suspect you'll be surprised and disappointed.
Click to expand...


That's why I said I know it can't be accurate.

I make this drive 7 days a week. It's 54 miles round trip, 40 miles is on I-95.

I fill up once a week with my gas gauge getting near the 1/4 tank mark. I'm not complaining.

i-bZ3V3h2-X2.jpg
 
WooD said:
That's why I said I know it can't be accurate.

I make this drive 7 days a week. It's 54 miles round trip, 40 miles is on I-95.

I fill up once a week with my gas gauge getting near the 1/4 tank mark. I'm not complaining.

i-bZ3V3h2-X2.jpg
Click to expand...
With that said, you're probably getting around 22 mpg, or a bit more. Thats about the same as I get with my tacoma driving mostly secondary roads.
 
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