Sorry.....had to get your attention from that hotbabes thread.

Anyway, ever since I rebuilt my '86 22re back in Jan. I've been getting between 17-18mpg. Yuck! I would think it would be better with all the new parts and whatnot.

Well, I know the tires were aired up to 30psi up front and 35psi in the rear. So, I went to check them the other day and they were down to 26psi up front, but remained the same in the back. So, out of the desire for better mileage I figured they needed more air anyway so why not go higher even. I'm now at 38psi all around.

However! Noticing my wife's stationwagon got 25mpg's last tank (up from 21), I decided I'd follow her little fill up method; top it off after every trip to town. On my way home tonight, the gauge resistered at 3/4's of a tank. Filled it up....it took 4.6 gal's...had travelled 80 (+) miles since last fill up, but I got 20.6 mpg's!!! Woohoo!!! I will keep tires up and top off after every trip from now.

Since this is only the first time I've done this, I will keep tabs.....as I always do.

 

I used to run a higher pressure than I needed in mine too but I got tired of my tires wearing bald in the middle. I just suck it up now and realize that these trucks just don't get good gas mileage and deal with it.

 

My Tundra gets better than your 22RE and it has a 5.7L V8!

 

15gal(tank) x 21mpg = 315mile(tank)
15gal(tank) x 25mpg = 375mile(tank)
375miles - 315miles = 60miles
60miles / 25mpg = 2.85gals
2.85gal x $4gal = $11.42

So you save $11.42 every time you fill up the tank (based on a 15gal tank) if you are getting 25mpg compared to 21mpg. Worth it right? Maybe.

Just keep in mind that if you're going over spec for tire inflation, you can balloon the tire causing increased and uneven tire wear eventually leading to tire failure and having to buy a new set. At what point is it cheaper to over-inflate tires for better mpg and sacrifice your tires later on down the road than keeping the tires at optimal pressure and getting the most out of your $500-1500 set of tires?

Lets say you're supposed to get 50k/miles out of your tires.

50,000miles / 315miles(21mpg) = 158.73fill-ups
158.73fill-ups x $60($4gal x 15gal[tank]) = $9,523.80($gas/life-of-tires)
50,000miles / 375miles(25mpg) = 133.33fill-ups
133.33fill-ups x $60($4gal x 15gal[tank]) = $8,000.00($gas/life-of-tires)

$9,523.80(21mpg-$gas/l.t.) - $8,000.00(25mpg-$gas/l.t.) = $1,523.80($saved)

So theoretically you'd save $1,523.80 over the life of your tires if you're getting 25mpg over 21mpg. Well, let's through out a number, and say that your tires cost $1000, and you'll only get 3/4 of your tires life if you over-inflate them.

50,000miles x .75(3/4) = 37,500miles
37,500miles / 375miles(25mpg) = 100fill-ups
100fill-ups x $60($4gal x 15gal[tank]) = $6,000.00($gas/life-of-tires)
$6,000.00(25mpg-$gas/l.t.) + $1,000.00(new tires) = $7,000.00

12,500miles(remaining miles to match e.t.l.) / 25mpg = 500gal
500gal x $4gal = $2,000.00
$7,000.00 + $2,000.00 = $9,000.00

So yeah, you still spent $523.80 less than had you kept your tires properly inflated, even with buying brand new tires. But, keep in mind that now you've already used up some of this tire's life expectancy trying to keep pace with properly inflated tire, so you'll be working through your 3rd set of tires while this guy's just finishing up his 2nd set.

So all in all, if you're planning on keeping your truck for another 100-150k+ miles, do all you can to save your tires. If not, eat them up and send me the money you saved getting more mileage since I did just solve world hunger. Hungover I might add. And I aint slept in 3 days. Plus I got heartburn. But I win anyways.

Ever notice that hunger and hungover both have the same first 4 letters? One has to do with wanting stuff to go down, and the other wanting stuff to come back up. So the difference would be the suffix yes? So "er" means down, and "over" means up? Guess that makes sense, cause if you're in the ER, than you went down somewhere for something. Right?

No TV and no beer make Clint go, something something.

 

My head just exploded after reading all that.

 

lol great post.

 

aren't you just a mathematician...

 

Owe ....my head !!!

 

DID I MISS THE 5 O'CLOCK FREE CRACK GIVEAWAY?

 

x2
Dude.....I think its time to put the glass pipe down.... And take a shower

 

He's an engibeering techinician. He can't help it.....


That's some good numbers there, Swampguy. But, it is just an experiment. I'll probably knock the tires down to 35psi next weekend. I just wanted to see what would happen.

I think mainly it has to do with the "top off" method. We'll see, though. I mean, I didn't change the tire press. in the stationwagon and it jumped almost 4mpg's.

Oh, and Brian....new trucks suck.....

Actually, I'm not surprised. Newer vehicles (okay.....newer "Toyotas") are designed a bit better.


BTW, Swampthing....I don't think I've EVER gotten 50k miles out of a set of BFG A/T's. I believe it's from hauling weight all the time and my country roads.

 

Holy underwear!!! And, I though you were asian all this time! My bad, ma'in....my bad.....:

 

Or, is it gaysian?......<<flop wrist>>

 

I don't think tires that are that severely over-inflated will last 50K miles before becoming unsafe from excessive wear at the center.

 

I keep my tire pumped to 40psi, and I dont care how much they wear, I just go down to the local pick and pull (now a scrap metal yard) and buy used tires for $5 each. The last set I paid $20 for, has lasted me 20k miles so far. all thes old bone yards are practically giving good tires away, its either that, or they have to pay to recycle them.. well, at least thats how it works up here. Now if you have a really nice set of tires, I would not recommend this, maybe pick up some cheapos for ev day driving and keep them pumped up, and then swap the others on for off roading.

 

True, i saw two baja claws like 33's but on a 16.5" rim (i think) anywho it wasn't the size i was looking for, but for like $10 a piece! maybe just under half life

 

it still relates to
1. how hard the rubber is (300 is normal)
2. i heard tires wear out from the inside/ more with air -less w/nitrogen
3. and IF (i stress if) we can save pennies on the dollar/ one flat/ or speeding ticket, that there counters it all out.

so, rule is. drive like its your last tank of gas, and have fun...

 

just something to think about:
tires operated on the road get hot. heat makes the air inside expand thus raising the tire pressure. the sidewall PSI rating of a tire is a conservative safe cold inflation pressure designed to take into account the heat caused by rotating the tire at speed and how it affects the air pressure inside the tire. increasing the cold inflation pressure of a tire reduces the safety margin the tire manufacturers have built into the tire. tires with too much air pressure blow out.

 

1. Yep. Has a correlation on the expected life of the tire.
2. The nitrogen filled tires thing is a myth. Don't make me break out the numbers again lol, I might burst my bbbrain (hah. funny medical joke if you understand it).
3. Yeah, but those are all just variables. I might get a flat and have to spend $311.97 on a new tire, or I could win a $100m lottery and get $96,153.84 a week for the next 20 years (or $65,000,000 lump sum). It's why we don't usually include what-if funds into the equation, though you could.

It's not a perfect depiction of what every single person would expect to see. It has a lot of values that can change. Gas price, expected milage of tires, expected mileage of over-inflated tires, initial mileage of vehicle, new mileage of vehicle, and price of tires. I just threw figures in there that I considered to be the mean, to give people a general idea. Plug in your own numbers if you want.

 

Absolutely. Which is also why I'm totally against retreads for highway use.