A science lesson in tyre design proved fascinating for editor DAVID HOOPER when he travelled to Portugal’s Algarve to test some new products from German manufacturer Continental.
WHEN was the last time you gave any consideration to the little circles of rubber which are the only point of contact between you and the road? Can you even remember when you last checked your tyres pressures?
Often overlooked, ignored, and taken for granted, your tyres are as vital a component to your vehicle as the engine itself – and in many ways – even more so.
Few people, however, have any comprehension of the technology and engineering that goes into creating those rubber circles, the crucial effect they have on the vehicle’s behaviour and the difference a tyre can make to the car’s handling, performance and fuel consumption.
All of these things and more were graphically demonstrated during a tyre testing session in southern Portugal’s beautiful Algarve region, home to the spectacular Autodromo do Algarve race circuit, near Portimao.
The event was staged by premium German tyre manufacturer Continental to introduce its two new tyres, the ContiEcoContact5 and the ContiSportContact5.
You may have seen the latest TV ads, and the company’s slogan, “when braking counts – you can count on us”. It’s a claim that isn’t made lightly, and one which has teams of engineers and scientists working relentlessly to uphold, and after the press conference held to launch these two products, I felt like I was back at school and had just had my brain scrambled by an advanced physics lesson.
To say that a modern car tyre is black circle of rubber with a tread pattern on it, is like saying that the space shuttle is a big glider which can also go into space. The technology behind them both is phenomenal.
The construction of the tyre involves several different areas – the grip zone, or the edge of the tyre, load zone or the base, the flexing zone or sidewall and the rigid zone, or belt, which attaches to the wheel rim.
Different types of polymers, rubber compounds, silicas and fillers are used to make a tyre which has to be resistant to cuts and tears, and the sidewalls have to be tough enough to withstand rubbing along roadside kerbs. Even the lettering on the sidewalls have aerodynamic implications.
Different sections of tyres are made from different compounds of rubber – the central part of the tread, for example, is made from a different type of rubber compound to that used on the shoulders of the tyres, or the sidewalls, and all these different sections are assembled in the final stages of production and baked together.
Continental Tyres has a massive production facility in Portugal which makes so many tyres that incredibly, it is now Portugal’s third largest exporter.
As carmakers put increasingly great demands on tyre manufacturers in the quest to drive down fuel consumption and C02 emissions, tyre companies face massive challenges in producing tyres which perform well.
Handling is heavily related to grip, while low rolling resistance is the opposite. These contradictory objectives create what is known as a Target Conflict – grip, versus low rolling resistance, without compromising safety. Continental’s engineers found the solution in new materials and compounds and the use of chemical engineering, working at a molecular level.
Numerous prestige and mass market manufacturers fit Continental tyres as original equipment on their vehicles, and we will soon see these new tyres rolled out on the cars we buy from our dealers.
Continental’s first proper eco tyre is called the ContiEcoContact5, is ultra light weight and designed specifically to provide low rolling resistance, which in turn provides better fuel economy and reduced C02 emissions.
It uses a harder rubber compound to achieve these characteristics, which in turn creates challenges in the areas of grip and stopping distances, yet Continental has achieved 120% improvement in rolling resistance over its predecessor, the ContiEcoContact3, a 110% improvement in wet braking, 112% improvement in wear and a 107% improvement in handling.
The other newcomer is the ContiSportContact5, a high performance tyre which is also being introduced for the first time into the SUV sector, and will be recognisable by “SUV” markings on the sidewall of the tyre.
The ContiSportContact5 will be fitted as original equipment by several manufacturers. The brief was to create a tyre with low rolling resistance and excellent wet and dry grip. To help the engineers achieve this, a compound called adaptive Black Chilli was developed.
The tyre combines rigid tread ribs and flexible blocks in the middle of the tyre to create flexible tread. To improve cornering performance, wider shoulder tread blocks were developed to improve the tyre’s footprint, or contact patch, when cornering hard.
This new tyre fits into the range just below the existing ContiSportContact 5P which is fitted to high performance sports cars.
We were also given an insight into the development of tyres for electric cars. These will need different properties to standard tyres. They will need to have low rolling resistance, but instead of being engineered for quietness, tyres for electric cars may have much higher noise limits to compensate for the lack of engine noise so they can be heard by other road users.
Speeds will also be limited to 100 or 120kph to preserve battery life, as higher speeds use more battery power.
The proof of all this technology and effort, however, was found on the test track, where we were presented with a selection of cars, from the tiny 500 Abarth, through to a Jaguar XF and the latest Audi A7, all fitted with the new ContiSportContact5 tyre. Other cars available for testing were a Mini Cooper, BMW 1 Series, the larger 5 Series, the VW Golf R and an Audi TT RS.
The undulating Portimao race circuit is superb, as anyone who watches the World Touring Cars or Superbikes will know. With lots of tight, low speed corners and fast sweeping bends, it’s a thrilling circuit to drive. It is also a demanding test for car, driver – and tyres. The ContiSportContact5 seemed to stand up to sustained abuse from drivers of mixed abilities very well, and at the end of the session, during which several high-speed laps were completed, the now hot tyres showed few signs of wear. The shoulders were still intact, and I was impressed that they didn’t appear to “go off” and lose grip on any of the cars I tested and after several “hot” laps. They consistently provided excellent levels of grip through corners and stopped well under heavy braking pressure, severe enough to activate the hazard lights on some cars which thought they were about to crash and automatically flash their hazard lights to warn following drivers.
But how would they fare on a wet track? That, we would find out later, after we had done another test designed to determine which of the three tyres was the most economical on identical VW Golfs.
The three tyres were the EcoContact5, the new tyre, the EcoContact3, its predecessor, and a developmental prototype tyre.
For this test, we had to drive the same route on public roads three times. GPS tracking technology and sat nav plotted the car’s progress, and each driver had to follow a graph with three lines on it, keeping the car as closely as possible on the centre line. It wasn’t easy, especially when you throw in hills, corners and the odd cyclist.
The fuel used was measured precisely on each lap of the course, and perhaps surprisingly, it was the prototype tyre which proved to be the most economical, being the one best optimised for the road. The new ContiEcoContact5 was second best, and the older EcoContact3 was the least economical.
However, as the next test was to prove, although the prototype tyre, with its harder rubber compounds provided the best fuel economy of the three, it also provided the lowest grip and longest braking distances on a wet surface.
Piloting 1 Series BMWs around a World Championship kart track, moistened by sprinklers (Bernie Ecclestone’s dream for Formula One) soon showed up the prototype tyre’s lack of grip on a wet surface in all departments – lateral cornering grip, traction and braking performance.
Getting into an identical car shod with the old ContiEcoContact3 tyre, and there was a marked improvement in the car’s handling, but the new tyre on the third car I drove, demonstrated a massive leap forward in grip levels in all departments, resulting in the shortest stopping distance and the fastest lap time on the wet track, almost five seconds a lap quicker than the prototype tyre could achieve.
While Continental tyres are not the cheapest on the market, the old adage “you get what you pay for” is certainly true. The people at Conti are clearly passionate about what they do and are rightly proud of their products.
Next time you need to change your tyres, try to think of it as an investment, rather than an inconvenient expense. After all, your tyres are the only things that keep you in contact with the road, and make sure you avoid contact with other motorists and the scenery.