The morning is going fine when in comes a customer clutching the latest issue of a magazine’s tire test. He lays the magazine down on your counter and says, “The experts here say that this tire is the best, so I want a set on my car.”
Why not just give them what they want? Because, according to Bob Strange, a tire and vehicle test engineer who’s done testing for manufacturers around the world, your customer might be badly disappointed. Even though the customer told you specifically which tire they wanted, if they are less than what he hoped for he’s likely to blame you. You’re supposed to be the professional, right? And besides, none of the magazine guys will be around to yell at.
The biggest problem with any testing, especially the limited testing done by most magazines, is over extrapolation. How many sets of each tire were tested? Was the sample size reasonable? Are the test tires the same as the tires available to the customers? Tire construction changes constantly, even within the same SKU; tires of the same brand and line but with different SKUs may differ significantly.
It’s also difficult to extrapolate data across different aspect ratios and sizes. Four-rib tread patterns of smaller sizes may have considerably different characteristics than the same brand/line tires with five-rib patterns. Different sizes and aspect ratios don’t have the same flex points and their on-track characteristics often differ appreciably. The magazine’s test may have been set up and run properly, but the rankings among a group of P235/50R18 tires may be significantly different than those of the same tire in P205/60R16.
Predictions of treadwear are particularly troublesome. According to Strange, it is unrealistic to expect a magazine to do credible wear testing. Proper wear testing is so time consuming and expensive that only manufacturers or government-sponsored tests have any chance of getting it right. Magazines that attempt to predict tread life by measuring the treadwear during their tests and projecting that wear rate out are offering little more than guesses.
Subjective evaluations of handling, beyond broad generalities, are always open to question. How many drivers were involved in the test and what are their credentials? Different people like different things, even experienced test drivers. Also, subjective handling assessments based on tight, low-speed turns may be very different than those derived from high-speed sweepers, especially in the wet. For most customers, these subjective rankings will never have any real significance because they are unlikely to ever push their vehicles hard enough to approach the handling limits of their tires.
What many drivers refer to as “handling” is actually steering response and published tire tests often do a poor job of measuring it. An important factor in steering response is self-centering: the return of the steering wheel to the straight-ahead position.
Strange noted that the increasing popularity of electric power steering (because of its fuel economy benefits) has brought with it complaints of a lack of self-centering and wandering during highway driving. Much of the “feel” of electric power steering is artificial and this is becoming more of an issue when replacing OE tires because the steering has been programmed for a specific tire. A customer may end up replacing OE tires with significantly less responsive replacements and be unhappy with the result.
Lane change testing is frequently included in tire tests as a measure of maneuverability and safety. The significance of lane change testing is rapidly diminishing as more vehicles are equipped with electronic stability control (ESC). ESC monitors a driver’s steering input, selectively applies the brakes, and modulates engine power to maintain control. ESC can help drivers maintain control during emergency maneuvers or reduce speed to prevent running off the outside of a curve.
Introduced in 1995, the technology has been required on an increasing percentage of new cars each year. Beginning with the 2012 model year, all passenger vehicles have ESC. Although the capability of the tires is undoubtedly still important to how rapidly a particular vehicle can make a lane change, ESC has made the ability to safely execute the maneuver a non-issue for most drivers.
The road surface is another important variable in tire test results. Concrete is generally more abrasive than asphalt, and coastal areas that use shells in concrete or asphalt are even more abrasive. The abrasiveness of the test track can significantly impact tire wear and handling, especially wet traction.
If the testing was done on a track regularly used by one of the manufacturers included in the test, don’t be surprised if its tires excel there. It may be difficult to judge how a particular test site helped or hurt particular tires in a specific test, but it can account for some of the variability between tests conducted at different locations.
Understand Parameters
Information gathered from manufacturers’ new tire introductions can also be misleading. The manufacturer is understandably going to do everything it can to showcase the strengths of their new tire, especially against “competition.” There is no guarantee that the tire your customer buys will be exactly the same tire used at the introduction.
The tracks or test courses used for the introduction are also important factors. If the tires are great on high-speed sweepers but only average on tight turns, guess what the course layout is going to be like. What cars were used? An AWD vehicle can compensate for problems a typical front-drive sedan would struggle with.
What did they test for? Perhaps more importantly, what didn’t they test for; does the omission of a street portion of the test mean that the tires ride poorly or are noisy? How many competing tires were tested and how many drivers were involved? What tires were they? Were the drivers experienced test drivers or amateurs?
Even objective measures of handling (skid-pad figures, lap times, slalom speeds, etc.) aren’t perfect. The cars used in the test and the tire sizes are important variables. Cars all vary in how much camber compensation is built into the suspension; flatter tires require less camber correction and will test better than rounder tires on cars with limited camber compensation.
Stopping distances can be measured to the inch, but are the differences significant and repeatable? ESC systems are calibrated for levels of performance based on the OE tires and can prevent tires with higher limits from reaching their maximum potential. Similarly, anti-lock braking systems (ABS) have programmed rates of build-up and release which may not be compatible with a particular replacement tire.
Overall, when looking at test results, if a tire from a major manufacturer is way off the mark there is probably a problem with the test results. Major manufacturers regularly test against each other and are unlikely to put out something that is seriously subpar. On the other hand, a grouping of results that are close together likely indicates tires that are essentially equivalent in the real world.
Use to Your Advantage
None of this means that you should be afraid of magazine or online tire tests or the customers who read them. Customers armed with these tire tests present a great opportunity for a dealer to get into a customer’s head because they are interested in facts. But remember, unless you have a long history with a customer, the magazine or website almost certainly has more credibility than you do.
Rather than attack the test (or accept it as the gospel), look at what the test didn’t say. Use the test as an opportunity for you to establish your credibility.
A dealer should always know what kind of car the customer drove in and what tires are on it. Ask the customer, “Are you happy with the car now?” and “What do you want to change”?
Ride, vibration, noise, handling, treadwear and cost are all factors. Their relative importance to a particular customer will vary depending on how they drive and what the customer wants their car to do – and at what price. Consider what the customer says they want or need and how that stacks up against the test results. If the winner of a test had mediocre marks for noise and your customer thinks their current tires are too noisy, you probably ought to suggest something different.
“There is no one ‘best’ tire,” says Strange. “The critical question is whether a tire is suitable for the customer’s car and use.”
