Tire Pressure Cost me!

[bronsin]

I check my tire pressures once a month. In the summer I seldom add air. But when temps drop in the fall I find that causes the pressure to drop maybe 5 psi. From like September to November. I use 35 psi. My mileage is pretty constant between 35-36 mpg. But when I checked my psi Nov 1st it was like 31psi all four tires. My mileage for that period is ~34. I added air just before the last fillup. When I checked it today it was 36 mpg. Im still waiting for the winter gas drop in mpg!

[b_hickman11]

I thought NJ already had their winter gas?

[bronsin]

I dunno. Usually around or before this time with my ECHO my mileage went from 40-42 to 38-40 when the gas changed over. But Im still getting 36 with the new air in my tires up to snuff. I gonna check the sidewalls and pump them up to max now. But Im waiting for the other mileage shoe to drop.

[b_hickman11]

Maybe you filled up the 1st time with Winter gas and the 2nd time with a station that still had summer gas?

[BailOut]

Originally Posted by b_hickman11

Maybe you filled up the 1st time with Winter gas and the 2nd time with a station that still had summer gas?

While improbable that is possible , but lower tire pressure does indeed equal lower MPG, so regardless of the fuel type it hurt.

At least the OP corrected the issue before it cost too much.

[b_hickman11]

Yes, if you are running anything below around 25 psi it is probably killing your mpg. But I will take my 44 mpg @ 32 psi any day.

[Crims0n5]

once i got my pressure up to proper levels, my MPG skyrocketed. Then again cruising the ride from Torrance to Sonora prolly helped

[bronsin]

Originally Posted by b_hickman11

Maybe you filled up the 1st time with Winter gas and the 2nd time with a station that still had summer gas?

Its possible but I dont remember! Im hoping by some miracle my Yaris will be immune to winter gas and Ill still be getting 36 mpg in February!

[RUFFSTUFF]

Wow... glad you caught it... people could die from that lost 1-2 mpg... THAT WOULD BE HORRIBLE.

[blktiger60]

40mpg?
Ya, that doesn't happen in my car.

[bronsin]

Originally Posted by RUFFSTUFF

Wow... glad you caught it... people could die from that lost 1-2 mpg... THAT WOULD BE HORRIBLE.

Just think what would have happened if the tires were 25 psi!

[blktiger60]

Originally Posted by bronsin

Just think what would have happened if the tires were 25 psi!

You'd hit a bump and bend your wheel?

[BailOut]

Originally Posted by RUFFSTUFF

Wow... glad you caught it... people could die from that lost 1-2 mpg... THAT WOULD BE HORRIBLE.

Well said. The more oil we use the more we want to protect our supply of it, to the point that we've sent troops to die to protect the supply not just once, but twice in the last two decades. We've also been bopped in the nose for our foreign policies and clandestine activities, which also trace directly back to our desire for oil.

This means that the less we use, the less we have to use the military to protect our supply, which directly contributes to saving lives. Every little bit counts.

[RUFFSTUFF]

Originally Posted by BailOut

Well said. The more oil we use the more we want to protect our supply of it, to the point that we've sent troops to die to protect the supply not just once, but twice in the last two decades. We've also been bopped in the nose for our foreign policies and clandestine activities, which also trace directly back to our desire for oil.

This means that the less we use, the less we have to use the military to protect our supply, which directly contributes to saving lives. Every little bit counts.

If that's what you tell yourself to help you sleep at night then so be it. Can't argue worth a damn on the internet.

[RedRide]

Originally Posted by BailOut

Well said. The more oil we use the more we want to protect our supply of it, to the point that we've sent troops to die to protect the supply not just once, but twice in the last two decades. We've also been bopped in the nose for our foreign policies and clandestine activities, which also trace directly back to our desire for oil.

This means that the less we use, the less we have to use the military to protect our supply, which directly contributes to saving lives. Every little bit counts.

I don't think so...
Let's not loose sight of the fact that "gas" is simply a by-product of refining oil.

If we stop using gas tomorrow, we would still need just as much oil for all the other products we get from oil from jet fuel/diesel fuel to plastics and everthing in between.
This a a littlt detail that the polititions always seem to conveniently forget.

Even in WWII we did not have a serious gas shortage. Gas was rationed mainly because the US government did not want people to wear out their tires as synthetic rubber was not yet fully developed and rubber was in short supply.

[sbergman27]

The general rule of thumb, based upon Goodyear's testing, is about 0.3% decreased fuel economy for every 1 psi *below* the number recommended by the auto manufacturer. So if all four tires are low by 5 psi, one might expect to see about a 1.5% decrease in fuel economy. Presumably, this is for combined mpg. The difference would likely be lower for highway, and higher for city, since wind resistance dominates the highway mpg figures. And I would expect to see diminishing returns as one goes *above* the recommended pressure.

[docB]

I run 42 psi in the fronts and 35 psi in the rears. I have averaged 39 mpg since I got the car in Aug of last year. (Cash for clunckers) I have a 5 speed and I'm not afraid to use it. I have gone to the red line in several gears. The car rides just like a small car. I have no bad tire wear. It takes ramps at speed limit times two + reasonable and prudent. I'll probably auto cross it this way soon. Oh yeah, 15" rims on my sedan.
doc

[silver_vios]

Originally Posted by sbergman27

The general rule of thumb, based upon Goodyear's testing, is about 0.3% decreased fuel economy for every 1 psi *below* the number recommended by the auto manufacturer.

So if I run at 1 PSI I'll still get over 29 mpg? You can't use a straight line for an exponential curve.