Fuel Milage for your 2nd Gen Taco..

I run my 215's at 40.
I ran the Sears tires on my '91 Escort at 45... pulled 60k out of them and they were warranted to only 40k... cheap shit tires but they lasted.

Got the Firestone Destination LE on the 5-lug. It has 53k on it when I bought it, no clue of the mileage on the tires.
I have over 100k now and they are showing no signs of wearing down.

 

You know I've experimented with different pressures and have not noted much difference. It does seems logical that rolling resistance would be reduced with higher pressure. That being said, I'm not sure how much power is required to overcome just that portion of what is required to move the truck (though I'm sure it's out there somewhere). I will say this, I'm not one to ever run the tires below the (vehicle) manufacture recommendation so maybe that's why I'm not seeing the gain? The data label on my truck calls for 29 psig front and 32 psig rear...not sure if it's different for different Tacoma configurations.

 

I've been running high inflation pressures since before BO was elected to the Ill state senate.

 

I meant more along the lines of more PSI gets a diminishing return but you increase the harshness of the ride

 

That only applies to the stock tires

 

There is a slight reduction in rolling resistance on a lightly loaded tire at higher inflation levels, but also there is less sidewall flex and tread squirm, which reduces heat buildup in the tire, and extends tire life.

I'll agree that once you get to 35 or so, you're reach the point of diminishing returns. Ya, 40-45 will get you a little more than 35, but the difference from 35 to 45 will not be nearly as great as the difference from 25 to 35.
Beyond 35, the main difference is resistance to hydroplaning....

Navy tests at Pax River determined that the speed at which hydroplaning will begin is directly proportional to the inflation pressure. This is without regard to fancy tread patterns... they help very little. All that matters is that the tread depth is less than the depth of the water (any tire will hydroplane once the water is deeper than the tread).

"Speed (in knots) = 9 X the square root of the tire pressure (in psi.)"
"Speed (in mph) = 10.4 X the square root of the tire pressure (in psi.)"

28psi = 55mph
32psi = 59mph
50psi = 74mph

Contrary to common misinformation, higher inflation pressures INCREASE wet traction.

 

http://www.fueleconomy.gov/feg/atv.shtml

To me this is interesting. According to the site rolling resistance is 5 to 6%. I guess even if I achieved a 10% reduction in overall rolling resitance I would only see about a half of one percent gain in fuel milage...maybe.

 

Except when the designer puts the suspension in the seats, the thing rides like a covered wagon unloaded at any inflation.
I really don't notice a more harsh ride at my normal pressures compared to where the tire shop sets them when I go in for a rotation/balance.

 

Outside of the fact that gasoline engines are incredibly inefficient heat pumps (come on Toyota, we need Diesel!), most of our efficiency losses (on any pickup) is aerodynamic drag.
Keep your speed down to 60-65 and you'll same a metric shitload of money compared to pushing 5 over the limit.

My best tanks have been driving in moderate traffic, where I can't quite get up above 60, but I'm not in a constant stop and go. 26mpg.

My worst tanks have been all highway... in New Mexico and Texas rolling 80. 22mpg.

 

Interesting , I see my best mileage when I get off island and hit the highway

 

Interesting, so using that fomula my fronts hydroplane at ~56mph and the rear at ~59mph. Seems the weight would play a roll but???

 

Those all seem like decent numbers to me Rich. I drive interstate I would guess 85 to 90% and I'm really easy on it hardly ever going over 70mph and only using the a/c when required (not easy in the deep south). I'm lucky if I hit 20.5. It's typical for 19.5 to about 20.4. I'm actually pretty happy with those numbers for this truck but, it's the 120 miles a day that gets me.

 

Stop and go is a killer.

Anything below 40-45 and you are not running the TC locked up, so you have huge losses in the transmission.

My worst indicated mileage on my Ultragauge is after a day of local shopping with my wife... which often includes some freeway... worst one was a few weeks ago when I was reading a tank average of only 15 when I hit the freeway to head to work Monday morning.
Ended up with around 23.5 for that tank overall.

45-60 is the sweet spot. 65 is still going to do quite well.
70 and it'll start dropping, but IMHO, is still a good compromise between maximizing fuel consumption and minimizing frustration of both the driver and those behind him.

 

Most of mine is at 45 - 50 and under locally

 

The report that I read (this was back in the 80s) did not indicate any relation to the weight. It was simply a matter of the water not being able to get out from under the rubber.
Also interesting was the report indicated that tread pattern made no difference. This is why aircraft tires simply have longitudinal grooves... they don't need a block pattern for their use (pure straight line braking and holding a vehicle in a straight line).
Road tires do have some different needs in that they are subjected to long periods of steady load, while AC tires have short periods of extremely high loading and heating. For automotive tires, the "block" tread and siping help to reduce running temperatures... but the "Aquatread" deal is pure marketing. Straight line acceleration, braking, and corner holding, a simple straight grooved aircraft tire is just as effective as resisting hydroplaning as an Aquatread.

I don't sweat the AC. If I'm warn or starting to break a sweat, I turn it on. At speeds above 40mph, you actually save gas running the AC vs running with the windows down.

Of course, a true hypermiler will have the windows up without the AC.
Fuck that.

 

http://www.popularmechanics.com/cars/how-to/products/best-tire-brand-comparison-test-2

Just a quick look at the top two tires on page 2 you can see the difference in tread pattern. The stats (bry and wet braking ect) are included. Doesn't seem the difference is that dramatic.

 

IIRC they are load range D and max pressure is 65psi. The Coopers have a softer compound than the KM2. I started at 65 and kept lowering the pressure a few psi at a time then running for 20 miles until I saw full contact patch at 55 psi during the summer. Now that it is colder and the compund has stiffened a little I have dropped to 50 psi. There is sidewall bulge that you wouldn't see in a harder coupound and they are 10 ply for wheeling. I also have the firstone air bags that I run at 5psi empty and at 45psi when carrying 1ton of topsoil. At lower pressures the outsides of the tires howl and just melt off so why run lower pressure on pavement? I wheel at 25psi in the warmer months and will probably try 20psi now that it is cooler.

 

You can see the bulge and contact wear out to the edge. I also have one showing the air bags.

 

10 ply D ? I thought D was 8 ply

 

My last set of tires I ran 55k abusive miles and ran 50 psi unloaded ans 55-60 loaded heavy. The also wore pretty good so I believe you lol..

The problem I had was every time I went to get them balanced etc they would drop the tire pressure down to what was in the door and it was way too low..