- David Hort
Tyres aren’t just black and round
“Tyres aren’t just black and round pieces of rubber".
It’s an obvious message that was repeated time after time at a recent experience event, organised by Continental Tyres.
While it may be a crashingly obvious observation, it’s what the majority of motorists think. To the untrained eye tyres are one of the most uninspiring features on a new car. Alloys can be exciting but UK motorists tend to overlook the rubber in which they’re shod.
That’s something that Continental – one of the leading premium tyre makers– hoped to change at the event at MIRA’s famed and highly secretive testing facility in Warwickshire, amid concerns that legal tyre tread depths are insufficient in terms of safety in wet weather.
The lifecycle of a tyre
Continental spends £100 million every year on research and development of new tyres so while the shape remains the same, the tread, composition and performance requirements are constantly changing – much more than you’d think.
Tyres aren’t just fitted to new cars, they’re tailored to suit that particular model at launch, as each tyre manufacturer battles for their piece of original equipment (OE) to be selected from the 200 tyre manufacturers in the UK alone.
That means a rigorous period of research, development and testing to get to the point where a car-maker will select a particular brand; the manufacturer can either accept the product or offer some suggestions on how it can be approved again.
The new Range Rover Evoque’s tyres took four years to be developed and produced from start to finish. As we’ll see, bringing a new tyre to market can be painstaking stuff.
Stages of development
1. OE Requirement – This usually starts with a concept car which will come with certain criteria for the tyre maker to fulfil, namely size, vehicle type and load/speed indices.
A reference tyre is picked by the vehicle manufacturer (normally a successful tyre of old) and the tyre manufacturer aims to improve on the standards set by that reference point.
Numerous applications are made to the car manufacturer with design evolution taking place until a successful tyre is picked. The whole process can take three to four years.
2. Mould design – Computer technology will predict how the tyre will perform based on the requirements set out by the car manufacturer. A tyre and mould will be created at the end of this development process.
3. Tyre construction – From that point initial tyres are built from a range of materials and components, including steel belts and nylon, before a tread pattern is etched out.
More than 30 different components are used in a premium tyre. As well as Kevlar there’s natural and synthetic rubber, mineral oil, silica and sulfur.
4. Compound choice – Different compounds are used in tyre construction and it is essentially the only part of the tyre manufacturing process which remains secret. Tread patterns, for example, can be copied by other manufacturers.
60,000 compound samples are submitted each year at Continental.
5. Building the tyre – Prototypes are built and then tested internally to ensure they meet the required standards set by the tyre manufacturer itself.
Moulds aren’t finalised at this point and each prototype is made individually. Because tyres are checked, faults could still be flagged up and an incorrect mould is expensive.
6. Indoor objective testing – Once the prototypes have been built, they undergo intensive testing indoors covering aspects like rolling resistance, endurance and high speed capability.
The tyres will not be tested on the car but using computers under controlled testing conditions. That’s because the cars may not have been built.
7. Noise and vibration tests – The tyres are put through a number of tests to make sure that vibrations and noise is optimised for the manufacturer.
The tests don’t look to eradicate noise and vibrations completely but ensure that feedback through noise and vibration is suitable for the car.
8. Outdoor objective testing – Tests of the tyres are moved outdoors where computers and machines will again test the tyres in controlled conditions. Tests include wet cornering, dry braking and aquaplane analysis.
Manufacturers will often be on hand during these tests to ensure the tyre meets the requirements of their new car.
9. Basic handling optimisation – A driver from the tyre manufacturer will then test the car and tyres together, assessing its handling and performance through a range of different criteria including balance, handling and comfort.
They will then report back with areas for the tyre to improve upon.
This process can be repeated again and again until the correct standards are fulfilled. These criteria will also depend on the philosophy of the manufacturer – so, a tyre tuned for Porsche will be dramatically different to a Jaguar-tuned tyre because Porsche places more emphasis on performance than Jaguar, which is tuned towards a combination of performance and comfort.
10. Joint tests – The car manufacturer will then perform its own tests with the subjective driver from the tyre maker. Again, if any improvements are required, they’ll be suggested by either manufacturer.
11. Approval – The vehicle manufacturer will then perform its own tests and if criteria and requirements are met, the tyre will be approved.
Even at this late stage, tyres can be refused approval and more changes requested by the vehicle manufacturer.
12. Production – If a tyre is approved it will go into production - up to three or four years after the whole process started.