Tire pressure has a measurable effect on fuel economy. In my car, it can make over a 3 mile per gallon difference and if you’re a heavy commutter that makes a noticable difference in your fuel expenditures. Take for example my typical commutting scenario:
- One way is 38 miles, for a total of 76 miles a day.
- That’s 1,520 miles a typical work month (76*20).
- At 40 miles per gallon (of diesel ) that’s 38 gallons of fuel (1520/40), and at an example price of 3.99 per gallon that’s 151.62.
-Now that same commutte with low tire pressure at 37 milese per gallon (of diesel) consumes 41.08 (actually 41.08108 repetand 108) of fuel per month, which at the example price of 3.99 per gallon is 163.91. That’s a difference of 12.29. Not a lot of money, particulary given how many miles that’s spread over, but it’s 12 bucks all the same. Multiply that times 6 months of not checking your tire pressure, and it adds up to 73 bucks.
What if you have multiple cars in your family ? That’s even more fuel and money wasted.
Keeping your tires properly inflated also yields better traction, better handling, and longer tire life. When tires lose pressure they change their shape, and all of their traction and performance characterstics change.
How often do you need to check your tire pressure ? If you’re like me, and hauling lots of equipment (I’m in a band) then I estimate you need to check your tire pressure at least monthy. At a minimum you need to check it with seasonal weather changes (this means at least 4 times a year), as well as before or after any long road trips.
Here’s a couple things you need to know though:
1. Don’t use the pressure gauge on any air compressor.
To properly maintain your tire pressure you need a couple cheap tools, namely a real pressure meter. The meters on the pumps at gas stations are worthless, as are those little pen shaped gauges. Go to a car store, a super-department store like walmart, and buy yourself a decent gauge like the one I have pictured. They’ll cost you about ten bucks, but will give you a much more accurate reading. Also buy a small compressor – the type that’s powered by your cigarette lighter and add that to your small bag of emergency tools and supplies you keep in your trunk (you DO keep a bag of emergency tools like jumpers and a flashlight in the trunk of your car, right ?!?).
This is the right kind of pressure gauge to use.
2. Check your tire pressure first thing in the morning.
The pressure of a tire changes as you drive it; the tires literaly warm up and the air inside them expands. Tire pressure specifications are meant for COLD tires, so check the tire pressure first thing in the morning before you drive the car anywhere.
3. Open the driver’s door. Why ? Because as you look down inside the door panel you’ll see a sticker that tells you what the right pressure for your tires is. THIS IS THE ONLY SOURCE YOU USE ! Don’t use anything else, including stuff printed on the tire (because it’s the vehicle manufacturer that determines the correct pressure for the correct performance characteristics for their vehicle), don’t use anything in a Haynes manual, anything the sales rep told you. Check the sticker. It’s the authoritative source and there’s a reason they are placed in a uniform location on all vehicles.
4. Always check all four tires.
Don’t assume that they lose pressure evenly – they absolutely do not. This morning I checked both my vehicles and found a 10 psi difference between tires on the same vehicle. Yes, it’s been too long since I checked the pressure if there was such a difference. I’ve had a rough winter (haven’t we all !). Point being though, actually check all four tires because there *will* be a difference between the front and back tires, and sometimes even left side versus the right side ! For example, my rear tires on the Jetta were around 20 psi (not good ! ) while my front were around 30 psi. I think hauling band equipment accounts for that difference. On our van however, which is less than one month old, one side of the van was at a solid 35 and needed no topping off, while the other side of it was around 32 psi. Why was the left side pressure higher than the right side pressure ? I’m not sure, although possibly the sunrise had something to do with it. Either way, all tires on both cars are now at the correct pressure, so we’ll save fuel and I can drive more confidently.
I hope this helps some. If so, leave a comment. Spam links will be deleted as always.
