When asked about the last time you thought about your tires, your answer probably falls into one of three categories, regarding how much it cost to replace them the last time, the last time you had a flat tire, or if you happened to notice that one of your tires was low. Considering that your tires are your only contact with the road, it only makes sense that we really should be paying more attention to them!
Your Family’s Safety is Riding on Your Tires
Please forgive us for the pun, but your family’s safety, not to mention the safety of other drivers, pedestrians, cyclists, and animals, is literally riding on your tires. Think about it. The only thing that allows your car to accelerate, brake, and turn, is the fact that you have a small patch of rubber, about the same area of four size ten sneakers, planted at four corners of your vehicle. Considering that the average car weighs something on the order of 3,000 pounds, more or less, that’s a lot riding on your tires!
According to the US NHTSA (National Highway Traffic Safety Administration), an average of 1 in 11, or 9%, of all accidents are related to tire problems, such as blowouts, tread separation, and poor traction. Tire safety is generally related to three factors…
Tire Pressure – Each vehicle and tire combination has a specific pressure to which the tires should be inflated, 30 psi (pounds per square inch) or 210 kPa (kilopascal), for example. At that pressure, your tires strike the right balance between ride comfort, fuel economy, and traction. Traction, when cornering and braking, is severely reduced when your tires are underinflated. Additionally, underinflation is the leading cause of tire blowouts, and the sudden loss of traction can easily lead to loss of vehicle control.
Tire Tread Depth – It might seem counterintuitive that lower tread depth could mean poor traction. After all, race cars run on slick tires with almost no tread, putting more rubber in contact with the track! On the other hand, let’s not forget that the race track is a clean and controlled surface, designed to run slick tires. For the rest of us, tread depth becomes critical whenever there is rain, dirt, or sand on the road.
The tread pattern digs through loose surfaces and squishes out water, so the tread blocks can grip something solid. Depending on prevalent conditions where you live, most technicians recommend changing tires by the time they’ve worn to 2/32” or 1.5 mm tread depth. In rain, dirt, or snow, we recommend at least 5/32” or 4 mm tread depth. Losing traction in these cases could lead to a loss of vehicle control.
Tire Condition – One important factor, aside from tread depth, which is a measure of wear, is the age and condition of the tire itself, because tires typically only have a lifespan of only five to seven years. Even if you don’t drive your car that much, the rubber and other components of the tire degrade over time, including dry rot and cracking, even that spare tire that’s been hiding out in the trunk since 1992. When considering the condition of your tires, look for unusual bulging or lumps, as well as for excessive cracking. Tires in poor condition could suffer from catastrophic tire blowout or tread separation, and a loss of vehicle control.
Tire Maintenance Saves Money
As we’ve seen, tires are of critical safety concern, but they’re also directly related to the running costs of your vehicle. Of course, you have to buy tires, and they’re a wear item, which means that you’ll have to buy them again, but they also directly affect your fuel economy, which determines how much you spend refueling every week. Imagine a 2005 Toyota RAV4, which typically delivers up to 30 mpg on the highway, with tires set to 26 psi. Tire maintenance essentially breaks down into three areas…
Tire Pressure – While we touched on how tire pressure affects your car’s safety, it also affects your car’s fuel economy and how long your tires last. Again, each car and tire pressure has been specified to deliver the best balance of traction, comfort, and fuel economy. Increasing tire pressure would make the tires more rigid, reducing the amount of rolling resistance, and increasing fuel economy. Conversely, reducing tire pressure would make the tires softer, increasing rolling resistance and decreasing fuel economy. Aside from affecting fuel economy, however, tire pressure also affects tire wear.
If tires on our theoretical RAV4 are supposed to run at 26 psi, this is supposed to deliver the best wear characteristics. Tires on the RAV4, depending on maintenance, driver habit, and tire type, may last as long as 30,000 miles wearing out evenly across the surface of the tread. Underinflated tires, aside from exhibiting reduced traction, will also wear out the shoulders more, while overinflated tires may deliver better fuel economy, but wear out the center of the tread more. In either case, you may end up spending more or less on fuel, but definitely more in tires, since they’ll wear out faster.
Wheel Alignment – It is good practice to have a wheel alignment performed when you get a new set of tires, or if the car is pulling to one side, or even if you hit a pothole or curb. The suspension components, in a well-aligned car, angle the tires to just the right degree, to keep the vehicle tracking straight, as well as to aim the wheels properly in a turn. On the other hand, a poorly-aligned vehicle may pull to one side or the other or squeal or scrub when going around a corner, both of which result in abnormal and excessive tire wear, which means you’ll have to replace your tires sooner than normal.
Tire Rotation – The tires mounted on the front and rear of your car serve different purposes, and therefore wear slightly differently. Front tires tend to wear the shoulders slightly more, since they are used to steer the car, while rear tires tend to wear more evenly across the tread, since they are generally just trailing behind. To even out this wear, regular tire rotations should be performed every 5,000 miles.
All in all, a good set of tires, well-maintained and properly adjusted, can last a long time, save you money on gas, and prevent accidents. Be sure to ask your mechanic about the state of your tires!