His job is all about driving at the limit. In rain and snow, Arctic cold and roasting heat, in a Porsche or a Polo. Angelo Perez-Riemer is a tire tester at Continental, which means he is one of the experts responsible for making driving as safe as possible. He explains to VisionZeroWorld how tires are put through their paces, why he travels the world for his job and why common sense is an important part of the testing business.
Angelo Perez-Riemer, you test tires at Continental. What is it that appeals to you about your job? Aren’t you just driving around in circles – like a racing driver, but with no rivals, no podium and no Champagne at the end?
Actually, I’m allergic to Champagne, so… Seriously, though, it’s not enough for us as testers to put in a few fast laps. Our job is to stay calm and switched on while we’re driving at the limit, to ensure we don’t get distracted for a second from what we’re here to do. Tire testing is a fascinating branch of in-car testing. It gives us as testers the chance to drive an extremely wide range of vehicles. So I might be at the wheel of a VW Polo in the morning and a Porsche in the evening. That means understanding and internalizing the concepts behind both vehicles and being aware of what each customer group expects from the car. So essentially, we assess every tire based on of the philosophy behind the vehicle we’re driving.
Tires are one of the key elements of a car in terms of safety and a significant contributor to “Vision Zero” – the pursuit of a crash-free future. How exactly does a tire test unfold?
Before you start testing a tire, you need to establish what it has been conceived to do. A new tire for a specific carmaker has to reinforce the idea that manufacturer has for their car. For example, a Jaguar F-Type has a different driving profile to a BMW Z4. And that means the tires have to “tell the same story as the car”, as we like to say. Then there’s the development of tires aimed at a particular category – like the replacement market. Here, my team and I select vehicles that are representative of their class and test the tires on them over a period of time. Tires for the replacement market are not universal items, though; they’re tailored to local markets. Customers in Asia have different priorities to their counterparts in the USA. There are many factors involved here, such as the climatic conditions, road infrastructure and the way people tend to drive in the various countries.
And then it’s onto the test track…
Not just yet. First we talk with the tire development engineers and discuss the content of the upcoming tests, what exactly we need to be looking out for and how the tires should perform on the road. It’s important to know what type of construction and material compound have been used for that particular tire. For instance, is it a winter tire that needs to work at temperatures as low as minus 25 degrees Celsius? Then the tires are fitted to the cars and we get started on the first test, which might be wet-weather handling. This means heading out onto a test track with sprinkler systems to simulate the tire’s characteristics on a wet country road. We lap the track as fast as possible and check our times. At the same time, we’re assessing the tire’s handling properties, its traction, braking and cornering abilities, and simulating realistic driving situations. In an emergency, a normal driver won’t necessarily brake before a corner, but as the situation demands. That’s a complicated thing to replicate in figures, so it’s our job as testers to deliver realistic and credible results.
So a human driver can assess a tire more effectively than machine-based testing programs?
Yes and no. For example, technical equipment is excellent when it comes to measuring straightline braking distances, because in such cases the objective data tells a more accurate story than human perception. However, only a human driver can ultimately sense any loss of directional control through corners under braking or acceleration and judge how “safe” the car feels. Of course we collect a whole heap of data when we’re testing tires, and this is important for the objective assessment of a product. But interpretation – through our human senses – is just as crucial.
To give you another example: Although measured data may show little discernible tire noise, the human ear might register something disagreeable, in which case the two sets of findings have to be reconciled. Here, tire testers act as the ears of the customer further down the line.
What happens after the wet handling test?
Then we test the tire’s performance on other surfaces, such as snow and ice, dry asphalt and off-road. First up is a dry road, and we normally focus on mechanical comfort and noise to start with. Then we move on to straightline stability, and steering/cornering characteristics at the limit of grip on the high-speed oval. This is followed by several laps of the handling course; one of our aims here is to record closely comparable lap times. It’s important to be relaxed for this part of the test, because you have to be very aware of what the tires are doing as you head through a corner at high speed. If we’re running a test with a sports car, we drive it as if it were a race. Then we push things to the very edge – and beyond – to see how the product responds in the most extreme circumstances. Our task is to explore the “red zone” − even though ideally customers will never go there themselves. The full answer to the question “how good and safe is this particular tire?” is provided by the various datasets on the one hand and our interpretation of driving impressions behind the wheel on the other.
You’re celebrating 20 years as a tire tester in 2019. Have you seen a lot of changes in the industry in terms of technology since you started out in 1999 – when it comes to the cars but also the tires, of course? Have the tests themselves also evolved?
They sure have. The reach of testing programs is increasing all the time, and our markets are changing. Over the years I’ve learned a great deal about various countries on my travels. There is a whole world out there beyond our base here in northern Germany with entirely different scenarios that you need to have seen and experienced at the wheel if you’re going to form an accurate picture of the market as a whole. Proving grounds can at best replicate the most common, globally prevalent road conditions. But that picture is inevitably incomplete. So the secret lies in gathering the most important information as efficiently as possible. Here at the Contidrom, though, we can accurately reproduce things like noise conditions in China – using a special subjective noise test. So we can at least make valid predictions.
But if you could replicate the whole world at the Contidrom, your work wouldn’t take you as far afield as the Arctic Circle, the USA and even New Zealand...
That’s right, there are some things we just can’t simulate, the weather being one. As we speak, two of my colleagues are out in the Arctic Circle, testing our tires on ice and snow. Others are running programs in Spain. Sometimes it just makes more sense to send tire testers around the world than sit here waiting for the right test weather to arrive.
How much time do you spend in a car every day?
I’d say about four to five hours on average. Approximately 60 percent of our day-to-day work in subjective testing happens behind the wheel. We see ourselves as advisors to the development departments who deal primarily with analysis of the “whats” and “hows”. And then we take our place at the wheel. Our assessments effectively guide the subsequent development work, so the guys have to be able to rely on our judgment one-hundred percent.
Driver assistance systems now play a big part in improving vehicle safety, and some of these work using sensors in the tires or wheel arches. For instance, Porsche has introduced a “Wet Mode” on the new 911, where sensors detect spray whipped up from the road and adjust the car’s settings to the amount of water on the road. Continental is also developing an automatic aquaplaning warning system which recognizes a loss of grip at an early stage and alerts the driver. Are these kinds of systems incorporated into tire testing?
Driver safety systems play an important role for the end customers and make a big contribution to Vision Zero – which stands for a crash-free world. And yes, we’re working on developments like the highly innovative solutions for early aquaplaning detection that you just mentioned, which trigger an early warning. I was discussing the details yesterday with my colleagues at Automotive. But it’s important to distinguish between the active safety systems on the one hand and the physical limits on the other. When we push the boundaries in tire tests, it’s the physical limits of driving dynamics we’re exploring. All active safety systems work solely according to these limits. This means our job is firstly to continually push back these boundaries and thereby achieve a continuous improvement in passive safety – where all the laws of physics come into play. Secondly, in subjective tire testing we have to determine whether safe performance is assured when driving at the limit. If the end customer inadvertently approaches the limit, it is ultimately up to the tires to ensure maximum safety.
Do you enjoy driving at the limit? Or can it be a nerve-shredding experience?
It does get quite exciting when you’re on the ragged edge. You need to enjoy driving fast if you’re a tire tester – and be able to stay cool at the same time. We’re working against the stopwatch, and every hundredth of a second counts. You could say that the driving itself resembles a high-precision mechanical chronograph at work; we are trying to set identical times lap after lap and in changing conditions. This is the key to collecting workable data and usable impressions from behind the wheel. At the end of the day, it’s all about keeping the end customer safe.