Posted by
Garnet92 on Wednesday, August 06, 2008 11:59:14 PM
On July 30th, Candidate Obama said “There are things you can do individually, though, to save energy. Making sure your tires are properly inflated — simple thing. But we could save all the oil that they’re talking about getting off drilling — if everybody was just inflating their tires? And getting regular tune-ups? You’d actually save just as much!”
Oh, really? Let’s look at that more closely (for the time being, I'm only going to address the 3% tire inflation aspect):
Under-inflated tires can lower gas mileage by 0.4 percent for every 1 psi (pounds per square inch) drop in pressure of all four tires. (Car Care.org)
For a recommended tire pressure of 30 psi (a fairly average norm), a 3 percent underinflation would require the tire to be at 22.5 psi. Using the Car Care formula (3%/.4% = 7.5 psi) and subtracting the 7.5 from 30 yields 22.5 psi. And note that the Car Care formula specifically states “of all four tires.”
That’s low enough to be felt in the handling of the car (assuming that you’re conscious), but may not be noticeable by a casual glance at the visual profile of the tire.
On a whim, I just checked my four on-the-ground tires and found them to be 31, 30, 29.5, 29.5. Proper inflation is 30 psi for these tires on my crossover SUV. I haven’t checked my tires, nor has the car been to a dealer for service in three months. In other words, I could not participate in the 3 % improvement that Obama talks about.
In order for that 3 % improvement to offset a sizeable portion of the oil that is anticipated from new drilling, how many autos would have to be currently driving around underinflated by roughly 6-8 psi? U.S. Dept. of Transportation says that there are 62,000,000 registered vehicles on America’s roads. It’s going to take a high percentage of those vehicles having four underinflated tires to add up to a savings equivalent to “all the oil they’re talking about getting off drilling.”
I’d sure like to see the numbers that the Obama campaign used to arrive at that statement. If we could get their source numbers and verify them, and arrive at a result reasonably close to justifying that statement, I’ll contribute $200 to the Obama campaign.
So, let’s make this a challenge: you Obamafiles out there, if you can get the numbers used to compute the factors substantiating Obama’s statement and they can be objectively verified as valid estimates, I’ll have egg on my face and Obama will get another $200. What could be sweeter?