Old school truck drivers always carried a tire thumper. It was a short, wooden bat that was always kept beside the driver’s seat. You’d see truckers get out of their truck, thumper in hand, and methodically thump sharply on each tire, from the steers and back around to the trailer tandems. If they didn’t get the satisfying thump and bounce off a tire, they knew it was low on air or even flat.
The other thing they would do is carry a penny to check their tread depth. They would stick the penny into the tread with Lincoln’s head upside down, and if the top of Lincoln’s head was still visible, it was time for new tires.
They still sell tire thumpers in truck stops, but nowadays professional drivers know that they aren’t enough. With increasing DOT inspections out on the road and CSA points counting against both the driver and the company, the smart thing to do is use a tire pressure and tread depth gauges.
Each tire on a vehicle should have 100 psi of pressure. It is just not possible to tell how many pounds of air pressure a tire has by hitting it with a tire thumper. You can tell it isn’t flat, but the thumper can’t tell you it only has 90 lbs psi.
Using a tire pressure gauge eliminates the guesswork and allows you to air up your tires accurately. Simply attach the gauge to the air valve stem and give a short pull. The indicator will pop out at the other end, showing the number of pounds by the line that is closest to the pen. These handy little tools are sold in truck stops. They may take a little more time during your pre-trip inspection, but trust me, when the DOT officer pulls out his tire pressure gauge, you don’t have to cross your fingers.
Find your groove
The tread depth gauge is another easy-to-use device. Simply push the plunger all the way down, which extends the probe. Then place the end of the probe, which looks like a screwdriver, into the bottom of the tread groove. Push down until the black plastic piece is flat on the tire. Then lift the gauge and read the depth from the indicator. The higher the number, the more tread depth the tire has. The gauge reads in both millimeters and 32nds. Steer tires must be at least 4/32nds deep; all other tires 2/32nds. Be sure to check the tire depth in the center groove and at outer grooves in several places on each tire.
Tire problems are one of the major things found at roadside inspections. Be prepared for the next time you are directed into a weigh station inspection area.
And the tire thumper? Some drivers just carry one for self-protection. I’ll leave that up to you!