Improving Gas Mileage - Installment 2

In a deperate attempt to keep up some momentum here, I am posting

Improvement #2 – Check Your Tire Pressure

Potential savings: $10 – 78 (0.4 – 3% improvement)

Cost: $0 – 75 and time to check and fill up tires

Cost of my recommendation:
$75 one time for a compressor (if you don’t have one)

Tire air pressure has a significant impact on gas mileage. Tire pressure decreases as a small amount of air leaks out over time or as temperature drops through the year. According to the US Department of Energy and the EPA, gas mileage decreases by about 0.4% for each 1 psi drop in tire pressure.

So if your tires are 10 psi low, your gas mileage will decrease by 4%. If you are getting 25 miles per gallon (mpg), that 4% translates into a 1 mpg loss. Low pressure will also lead to increased tire wear - you will have to pay to replace your tires sooner.

At the same time, overinflating tires can be a safety issue. An overinflated tire has less contact with the road and can be more unstable in braking or turns.

You can usually find your recommended tire pressure inside one of the two front doors, the glove compartment door, or the owner's manual (NOT on the tire itself, as I used to think).

These are recommended pressures when the tire is cold, so always check your tire pressure before you drive anywhere.

The cheapest way to check your tire pressure is to carry a tire pressure gauge in your car and check the pressure in the tires once every week or few weeks.

There are a couple of good products out there that make it easier to monitor your tire pressure:

A) Tire pressure stem caps - Tire pressure stem caps screw on to your valve stems (you know - those little things you use to check tire pressure) and turn yellow or red when your pressure gets low. These are also great to keep an eye on the pressure in your spare tire.

B) Automatic tire pressure monitors - These systems add sensors inside each tire and display the pressure of each tire on your dash. A number of new cars now come with this option. They are more expensive to buy and install but much more convenient!

Because most places seem to charge for air now, I have my own air compressor to air up our tires. If you don't have an air compressor, you may want to invest the $30 or so in an air tank.

You can fill this up at your local gas station and keep it in your garage to air up your tires if you need to. You could also invest the $75 or so for small air compressor to take out the middle man.

Having an air compressor is my personal recommendation to make it easy to air up your tires. And let's face it, the reason most of us (well, at least me) don't do this as often as we should is that it is too much hassle (and most gas stations charge for air now).

There are also small air compressors that can run off your car battery - they take a long time but are great in a pinch.

My recommendation:

For the convenience (and increasing the chances that you will check your tire pressure more often), get a small air compressor for your garage. Don’t carry it around with you in your car, though (see Improvement #6).

This improvement was pretty straightforward, but there will be a lot of new information (for most people) in #3 - Use Synthetic Oils. That should be up tomorrow!