1. All-season tires have better wet-road grip than summer tires. In which season will an “all-season” tire offer better wet-road traction than a comparable “summer” tire? Answer: None. To Southern Californians the seasons are Flood, Fire, Earthquake and Mud Slide: They think an “all-season” tire must be fire-resistant and good in mud. Meanwhile, to those in L.A. (Lower Alabama), the seasons are Summer, Deer, Duck and Turkey. They are appalled that “all-season” tires are not camouflaged. Here’s the truth: An all-season tire trades wet-road traction (among other things) for enhanced mobility in snow and in sub-freezing temperatures. Designing a tire is an exercise in compromises: Improving a certain tire performance, almost always means diminishing another–or several others. (Some more accurately use the term “three-season” when referring to summer tires.) To make things even more complex, switch categories (or even brands) and the results may change: An ultra-high-performance all-season tire may offer better wet grip than a high-performance summer tire or, especially, a grand-touring summer tire. 2. Plenty of tread means plenty of remaining tire life. Humans and tires are similar: Both can reach the end of their lives without having gone far or done much work. Just as a human who has never left his home state or his mother’s house can be ready for the grave, an old tire can be ready for the recycler even if it has deep tread. Some auto manufacturers recommend replacing tires every five or six years, regardless of tread depth. A tire that’s been on a car seven or eight years is much like a 65-year-old human: No matter how fit and healthy he looks, he shouldn’t play rugby against 19-year-olds, as a sharp impact or an aggressive maneuver could have unhappy results. If it’s 105 degrees outside, a simple stroll can be deadly to both out-of-shape older people and poorly maintained old tires. Here’s how you can tell how old your tire is: On its sidewall of find the letters “DOT.” Following that will be a sequence of numbers, which may be in three or four separate windows. The last four numbers tell when the tire was made: “3106” means the tire was built during the 31st week of 2006. While you’re on your knees, check for hairline cracks in the sidewall: That’s a strong indication the tire needs replacing. Deteriorating rubber is a big a problem for rarely driven vehicles, such as motor homes, collector cars, exotic cars, vehicles owned by senior citizens, and vans operated by charitable organizations. (A request: If you have older neighbors, check their tires for proper air pressure and signs of aging. And don’t let them play rugby.) 3. A tire will burst if the “max press” number on the sidewall is exceeded. A new quality tire will not burst even if the “max press” is exceeded by a very large amount. (I could tell you but then I’d have to talk to lawyers.) All bets are off if the tire has been damaged or it’s fitted on a cheap or damaged wheel. Coupled with the “max load” number, which is found near to “max press” on the sidewall, you can know the maximum load-carrying ability of a tire. Know this: It’s air pressure that allows the tire to carry a load. At one pound per square inch (psi) of air pressure a tire can support no weight. To increase its load-carrying capacity, air pressure must be increased. (Imagine a plastic soft-drink bottle: With the top off, it’s easily crushed, but new and unopened it can support a grown man.) However, at some pressure, adding more air to the tire will not provide increased weight-carrying capacity: That’s what the “max load/max pressure” means. 4. The “max press” on the sidewall is the proper inflation pressure for your tires. Fewer believe this than the previous item, but the misconception is widespread in the law enforcement community. The proper inflation pressures for tires are determined by the automaker (in concert with, but not by, the tire maker). The government now requires new cars to have that recommended pressure on a placard located on the driver’s doorjamb. On older cars this placard was often on the doorjamb, but depending on the car company, could be on the trunk lid, glovebox door, console lid, or fuel door. If you can’t find the recommended pressure placard, look in your owner’s manual or call your carmaker’s customer service department. Inflating the tire above the car manufacturer’s recommendation may make it more susceptible to damage from potholes and will reduce ride comfort. However, it will likely increase race-track-style at-the-limit performance. (I suspect this is why highway patrolmen run high tire pressures.) Back in the day when I raced showroom-stock cars, the rules required everyday tires rather than the made-for-racing specials now allowed. We always set the pressure far above the vehicle maker’s recommendation. When I ran front-wheel drive cars, I often used extremely high pressure in the rear tires: I was trying to reduce rear grip so the car would turn better in the middle of the corner. 5. Budget-brand tires are as good as big-name brands since they’re built by the same company. As with most products, rarely do you get more than what you pay for. It’s easy to see how this misconception developed. Each tire company has a premium brand upon which it focuses its research, development and testing. In addition, almost all produce other brands. Many build tires for others–such as auto-parts stores–to sell under the store’s brand. As you progress down this list, development and testing quickly drop to no more than legal requirements. The R&D from the premium brand often–but not always–trickles down into the budget brands. So maybe the difference is so small, you can’t tell difference. Or maybe not. News source: AutoMedia