Today’s topic is often one of the most overlooked aspects of vehicle maintenance, that of checking the tire pressure. This can be one of the most critical while at the same time one of the easiest tasks for the average motorist to perform. How often do we check the pressure in our tires? Monthly, weekly, or simply when we notice one of the tires looks less round than the others? Thinking about this a little more the tires are the only items in contact with the surface of the road at any time on our vehicle so it makes more than a little sense to make sure these items are tip top. Having written the former section of this post earlier today, I invoked what some might called tempting fate. I say this as I arrived at work this morning, I noticed a strange sound as I drove down the ramp to the first parking level. It sounded something like “fwap-fwap-fwap”. Onomatopoeia-esque to be sure. But no matter what your automotive diagnostic prowess might be, on a very basic level anyone knows that sound portends nothing good. The good thing for me is that “that” sound didn’t manifest itself until I was at work, and safely in the garage. Imagine the shenanigans that could have transpired had it happened on the interstate or boulevard with rush-hour traffic. The danger is two fold with a flat tire and expensive wheels. First the tire is flat, but now a quarter of your vehicle is directly pushing that one wheel into the pavement. It won’t be long if you continue driving that you will need to replace both the wheel and tire. And when it comes to performance vehicles that costly repair can exceed $1,800 per occurrence. Thankfully my tire/wheel combo is much further South than that. Thankfully.
This is what brings a frowny face to my, uh face. The sort of annoying thing about this situation is that I checked the pressure on all four tires the previous evening, and found this particular tire to be 1Lb. light, and so I topped it off. Got up this morning, and noticed that all the tires were round or un-flat. These are 19″ low profile tires, and run at higher pressures than your standard height sidewall radials. Volkswagen recommends these tires are best kept at 39psi.
So the question is how and when to check your tire pressure. First things first, it’s best to check the pressure when the tires are cold to get a true reading. If you take readings after you’ve driven for any distance the tires warm up and as a result the pressure increases in the tires. Best to take readings before you drive the vehicle for the first time that day, and recording those readings. Let’s call this first reading the “cold tire pressure” or CTP. If you find that the pressure is below the recommended level, just make a note of how much air is needed then find a service station with an air pump and top it off. Now, I know what your next question is going to be, “If you drive any distance the tires will expand and give me a false reading”. True, but if you’ve recorded the CTP before you drove to the service station then you already know how much you need to add to each tire. For example if your CTP reading was 30psi and your vehicle manufacturer recommends 32psi, then you know you know to add 2 pounds of air. You then drive to the service station, and re-take the pressure reading it now reads 38psi. What do you do? Add 2psi to your latest reading of 38, and check it again to see that it reads 40psi. Makes sense?
Now, what to use to take those readings? The worst thing to use, in my opinion, is the gauge at the service station as you have no idea how reliable it is or when it was last calibrated. Slightly less worse is the pen style “stick” meter. It’s difficult to read and not as accurate. Still, better in a pinch to have the pen style stick meter than nothing at all, and every motorist should include a basic tire pressure gauge in their kit. Better is digital gauge or high quality analog meter with pressure release valve. Try and avoid any of those one piece pen shaped digital meters. The gauge should be composed of the gauge housing and length of hose to ensure you can clearly read the dial face without having to double over the tire. Take a couple readings from each tire to make sure you get an accurate reading. While you checking the pressure you should also get in the habit of checking for any abrasions, punctures, bulges or other anomaly that could be indicative of more serious issues. This simple inspection can save you much more than you can count later when you’re under power and at speed. I’ve luckily only had two blowouts at speed, and they were not the fun-n-lively experience I thought they might have been.
The Golf R ended up being towed to a dealership close to my home, and the tow company was very accommodating while transporting my R. They delivered it without incident, and the VW dealer quickly patched the tire, saving me an additional $250. I spoke with the mechanic as they were checking the tire off the car, and they found that the tire had something embedded in the tread in the first third of the width towards the body. I was unable to see anything when I inspected the tire after the Tire Pressure Sensor (TPS) system warning light lit up my dash only a week after driving the Golf R home from the dealer. Beyond that initial warning, and checking the pressure weekly nothing changed until week 4, and at the end of the morning commute the item was finally dislodged letting all the air out, and me with a blog post to write. A picture of the actual puncture location is shown below for your own personal edification.