Balancing performance tires
Saying technology has changed over the last decade might be one of the greatest understatements that I’ve ever made. In 2005, tire pressure monitoring systems (TPMS) were primarily reserved for high-end luxury and sports cars. Anti-lock braking systems (ABS) and electronic stability control (ESC) were options. And people who thought the Blackberry was a smartphone were surprised when the first video was uploaded to a new video hosting service called YouTube.
Consumer expectations also have changed over the last 10 years. To most people, Yelp was something you did when you pinched your finger and the Internet was used for research and not for online reviews. If a customer had a problem with a retailer, he might complain about it to his friends or file an official complaint with the Better Business Bureau, but that was the extent of it. Today’s consumer is a highly connected smartphone addict who has, at his fingertips, someone else’s bad experience for every business documented for eternity. There is little room for mistakes in 2015. The tire industry is just like every other retail business in the sense that customer expectations are too often borderline unrealistic. Many of them still remember the days when tire companies advertised new tire prices that started at $19.99. Of course, that was for a P155/80R13, which only fit a handful of the cars at the time, but the perception was enough for consumers to believe that inexpensive tires were available.
According to data published by Modern Tire Dealer, the total number of replacement passenger tires shipped in 2005 was 205.8 million. Last year, that number was 206.6 million. However, in 2005, the total performance tire market was about 43 million tires; last year, it was just over 70 million. In other words, while the total number of replacement tires hasn’t changed much over the last decade, the percentage of high performance and ultra-high performance tires has increased dramatically. This explains why more and more people are driving “regular” cars with performance tires.
For consumers, this means the days of low cost replacement tires are rapidly coming to a close. The average overall price of a passenger tire has surpassed the $100 mark. For that kind of money, motorists expect a lot more, and they are less likely to overlook something like a vibration. Once they accept that performance tires are their best option, the hard work begins. Again, expectations are raised because they are anticipating a replacement tire that will perform at the same level as the original equipment fitment. The tire can’t do it alone.
From the balance perspective, it starts with the mounting process. The first step is to thoroughly clean the bead seat areas of the rim with a wire brush. Dirt, corrosion and foreign material trapped between the beads and the rim will not allow the tire to concentrically seat on the rim. Non-concentrically seated beads are an automatic source of imbalance that cannot be overcome by even the most technologically advanced balancing machines. I’m a big fan of paste-type bead lubricants because they seem to do the best job of allowing the beads to seat evenly while providing the best anti-corrosive properties down the road.
Another technique that has proven to be effective for concentrically seating the beads is to inflate the tire to the maximum pressure listed on the sidewall before completely deflating it. This gives the beads a chance to seat against the rim flanges and then relax before inflating the tire a second time to the recommended inflation pressure listed on the vehicle tire placard. It takes a little extra time, but studies have shown that this practice does improve uniformity and concentric bead seating. You can check to see if the beads are concentrically seated by measuring the distance between the rim flange edge and the molded ribs on the lower sidewall. According to industry recommendations, there cannot be more than 2/32 of an inch variation in that distance. Personally, I believe that any variation in the distance between the rim flange and the molded ribs is unacceptable, especially when mounting performance tires that will be installed on vehicles with more highly tuned suspension systems. It doesn’t always take a lot of imbalance for the driver to notice that something is wrong, so making sure the tire is centered on the rim must be the first step.
The next step is a combination of technology and training. Modern tire balancing machines have advanced diagnostic and runout measurement capabilities. They are capable of matching the high spot of the tire with the low spot of the rim to ensure the best uniformity of the rotating assembly. They can even make recommendations on where the tires should be installed on the vehicle for the best ride.
Again, the performance customer is expecting a lot more when it comes to ride and handling, so having the capability to match-mount tires is often necessary.
In the case of the economy car driver who is forced into a performance tire purchase, it might not be critical. But the true performance car driver of a performance automobile is unwilling to accept anything less than perfection. And for the SUV owner who spends upward of $200 per tire, even the slightest vibration is unacceptable, so taking the extra steps to ensure the balance is as good as possible is just good business.
But all the advanced balancing technology on the planet is worthless in the hands of a technician who is not trained to utilize the features on the machine. Too many retailers go out and spend tens of thousands of dollars on the latest and greatest balancers only to watch technicians set the machine to static because they don’t know how to use tape weights. And while the technology is there to make sure the larger SUV and light truck tires are as balanced as they can be, poorly trained and unmotivated employees continue to take the easy route resulting in costly comebacks and potentially bad reviews on the dreaded Internet. If I’m spending almost $1,000 on a set of performance tires, I expect a lot more than a basic static/dynamic balance.
Maybe the solution is to offer different levels of tire balancing. For customers who are primarily interested in saving money, the simple static and dynamic balance is the way to go (and possibly included in the price of the tire.)
On the other hand, the performance or SUV customer might see the value in paying a little more for advanced balancing technology.
Of course, that means the salesperson has to sell the value related to a match-mount, road-force, laser-guided tire balance. Premium tire balancing services can be marketed and sold in a way that makes it worth the investment to train technicians to effectively use all of the available technology to achieve the best possible balance.
The final step of performance tire balancing in a performance world is to invest in a set of pin-plate adaptors. It doesn’t make much sense to install the assembly on the balancer with the standard front cap and back cone when balancing performance tires, unless of course the technician is going to slap a weight on the back flange for a static balance.
If you are going to the trouble of utilizing all of the available technology, then it only makes sense that the tire is perfectly centered on the machine. And while the back cone front cap method is capable of achieving some level of precision, the pin plate method has been proven as the most accurate method for securing and centering the assembly.
Front caps vs. pin plates
In order to demonstrate the difference between front caps and pin plates, I conducted a brief test at a local community college. In the first test, I balanced a V-rated P255/45R18 V-rated performance tire on an alloy rim using the front cap and rear cone method. The machine that I used was capable of measuring road force, so I completed the necessary checks and measurements in order to determine how much was present. Tire road force was 74 pounds and assembly force was 68 pounds. After force matching, it could be improved to 66 pounds. When balancing the same assembly using the pin plate, the amount of tire road force improved to 54 pounds while the assembly improved to 57 pounds. After force matching, the road force would improve to 46 pounds.
It’s important to remember that nothing changed between the two balancing attempts. It was the same tire with the same settings and the only difference was the method for attaching it to the machine. In this instance, the pin plate would result in less weight being applied and a potentially better balance.
The second test involved a P275/55R20 that was installed on an SUV. Using the front cap, back cone attachment method, the tire road force was 25 pounds and the assembly road force was 26 pounds. After force matching, it would improve to 23 pounds. But the important thing to recognize is the runout measurements. Lateral runout was 0.029 inches on the inner flange and 0.024 inches on the outer. The radial runout was 0.018 inches on the inner flange and 0.015 inches on the outer. When the assembly was attached to the balancer using the pin plate, the differences in road force were minimal, 24 pounds for the tire and 23 for the assembly with an improvement to 22 pounds after force matching. But the runout measurements improved to 0.003 inches and 0.004 inches for lateral with 0.005 inches and 0.007 inches for radial runout.
These tests do not endorse road force or force matching. They are just intended to demonstrate the positive impact that pin plates have on balance and runout measurement. Performance tires and SUV tires with performance expectations will deliver a better ride after balancing simply because they are more uniformly secured to the machine.
This allows the technology in any balancer to be more accurate because the properties being measured are more precise.
A changing landscape
Clearly, the landscape of the replacement tire market is evolving to include more performance tires on vehicles that also are becoming more performance-oriented. And with tire prices for SUV drivers steadily climbing, customers who spend almost $1,000 for a set of four expect a higher level of vehicle performance. Balancing those tires can be accomplished a variety of different ways, but advanced balancers can achieve an unmatched level of uniformity if the features are fully utilized. In order for that to happen, technicians must be properly trained and have access to the proper equipment, like pin plates.
Customer expectations in a performance world are significantly higher. Since a growing number of them are more or less forced into a performance tire purchase, the margin of error when it comes to balance is as narrow as it has ever been in the history of the tire industry.
Performance tires are guaranteed to perform to some degree, but reaching their full potential depends on balancing practices that live up the definition. ■