Pirelli: racing yesterday, rallying today with techniques for tomorrow
As the astonishing publicity generated by their wall calendars fades into memories of 1974, Pirelli Ltd. in Britain have become one of the staunchest sporting supporters of all. Rally championships, a series of sporting forums and an accurate avalanche of publicity to exploit the company’s considerable competition success, all are designed to ensure others are aware that Dunlop and Goodyear are far from the only sporting tyre firms.
Ironically our research Nras conducted as the news came through of Ferrari’s Formula one intention to use Michelin. Just 20 years ago Pirelli were celebrating a year when Juan Manuel Fangio had won the World Championship driving a Maserati 250F. Although it might seem logical for Ferrari and Michelin to join forces in a Renault-Michelin-style F1 effort, there is a conscious Pirelli bias at present toward rallying. In the Milan skyscraper that acts as HQ to Pirelli today (raised on the site where the firm’s first building sprawled from its foundation in 1872) the feeling is that rallying Fiats, Opels, Toyotas and Fiats provide the best link between competition and normal road users,
Our purpose in talking to company representatives in Britain recently was to discover a little about the latest Pirellis, which hide under a bewildering number of designations. We wanted to know what the P3 and P6 and Plus One tyres did for the motorist, and the company. Originally we had thought that the P7 was a well-known quantity, but since that combination covers everything from a squat slick to tall Safari special rubber, even that required further elucidation.
Unlike Dunlop and Goodyear I can recall little being written about the Pirelli company in our pages, so a few general words should be useful. Pirelli is a business with strong family links, the grandfather of the present chairman founding the business 105 years ago. They quickly built up to about 40 employees, all able to pursue the applications of rubber through the aid of a 27-h.p. steam engine.
Today Pirelli employ 70,000 people, only 28,000 of them in Italy. The link between Dunlop and Pirelli is referred to at the Italian end as a union, rather than a merger. This is because all but the British Pirelli company retain a majority of Pirelli shares. In the United Kingdom, where 5,000 are employed mainly in Carlisle and Burton-on-Trent, Dunlop own 51% of Pirelli shares.
At the time Dunlop and Pirelli joined together, there was obvious direct competition between the companies, some of which has been eliminated. An example is Wellington boots on the Pirelli side, but they are still pretty diverse in their activities. Today 40% of all Pirelli business is tyres; 40% cables. The rest varies from those airport arrival and departure boards, newsprint and slippers.
As those with city interests will know, the Dunlop-Pirelli combine has encountered some pretty stiff losses on the Italian side since the union in 97:. In the last two years things have got considerably better: certainly on the car tyre front there has been exciting development with good commercial implications.
As a range of tyres the Pirellis tend to be somewhat confusing as the newer lower profile designs mingle with established names. Such names as the Cinturato (CF67), the immortal “Cint” that served the enthusiast of the nineteen-fifties and sixties.
Pirelli production consists of 93% radial ply tyres. It was in 1951 that the Cinturato started the company off on the radial road. At first there were few cars that were suitable to this tyre design: ideally the suspension needed to be drawn up with the Cinturato in mind. lAncias and Alfa Romeos were among the first to benefit: as their road-holding properties became known, a few more sporting manufacturers followed suit.
In 1959 the textile fabric Cinturato came to Britain, and it has remained in production at the Burton-on-Trent factory ever since. Even now, when that distinguished tread pattern might be regarded as a thing of the past, Leyland retain their affection for the “Cint”. The MG sports cars often come with these tyres, and Morgan use a few as well. The Rover 2000 was the first car in the United Kingdom to be specifically drawn around the advantages offered by the Cinturato.
In 1951 Pirelli had been the second company into mass production of the radial-ply tyre, albeit a textile radial. That French first company Michelin who have an even stronger grip on many areas of the tyre business today than even the considerable influence they previously exerted, set a pattern that could not be ignored: namely the steel-braced radial-ply tyre. High mileage coupled to good manners were traits that just could not be ignored; it is significant that most modern tyre makers have had to follow that Michelin lead in the end.
Pirelli’s steel-braced tyre for the enthusiast came into gradual use through fitment to some small volume specials such as the fuel injection Ford Capri RS 2600, which had adopted the CN36 SM (for Super Metallic: it had been a fabric-based plain CN36) by the early 1970s.
Ford, Opel and many others showed a preference for the SM Pirelli and it gradually spread from the enthusiast saloons (many of the FAVO Escorts rested on such covers) to the same kind of widespread acceptance enjoyed by the Cinturato. Ironically the new, live axle, Rover 3500 is a typical mass production example of the effectiveness of the CN36 SM.
The CN36 is very much with us today. Ford use it on the RS Escorts; Opel (Commodore and Kadett GT/E), Alfa Romeo (2-litre Alfettas), Lancia (mid-engined Monte Carlo and top level Beta saloons) but the real prestige lies in the success of the Pirelli-Veith organisation in West Germany. The CN36 SM is specified for Porsche 9245 and is offered for the non-turbo Porsche t is. Every German car maker takes CN36 on at least one member of its line, though in VW’s case the company actually only list the fuel injected Audi 80 GTE and the five-cylinder 100.
In fact the fabulous 100-b.h.p. Golf GTI came on CN36 SM when I tested it in this country. I remember it particularly because the CN36 SM can be quite a handful in the wet on a live axle, front engine layout. On the FWD Golf the Pirelli was magnificent on some of the nastiest greasy conditions of 1977, and proved capable of maintaining extremely high speeds with a marvellous feeling of stability. This applied particularly to braking and cornering characteristics: ito b.h.p. applied through the front wheels sharply is bound to provoke some wheelspin when accelerating hard.
Other CN36 SM fitments include SAAB (again good on the EMS, a FWD 118 horsepower device) and the 3-litre TVRs.
The latest conventional tyre design, this time using a. steel and nylon construction that has much in common with Pirelli’s current competition covers, is the P3. The British company were offered the straight steel-belted CN54 design as an interim between fabric radials and the steel and nylon system offered today, but they declined, preferring to prepare the British factories for either textile (Burton-on-Trent) or steel and nylon-based covers, the latter emerging from the moulds at Carlisle. The CN54 cover did arrive in Britain, but only to replace similar covers already fitted to the Fiat 127.
Thus the next major step in Britain was the adoption of the P3. This extraordinarily versatile tyre has the steel and nylon construction and has been produced in Britain since the Spring of 1974. It is far from the low profile, squat covers that are now corning in from Italy, but they all owe something to that popular (on the Continent) competition tyre range designated P7. Meanwhile, suffice it to say that the P3 is a very widely accepted tyre that competes in much the same area of the market as the Michelin ZX series, the real mass production part of the market; though you will also find them on Fiat’s X1-9 two-seater.
The new generation of ultra-low profile l’irellis tend to be marketed under the collective Plus One term. A little confusing as the only real example of the Plus One philosophy is actually called the P6 on the sidewalls of the Fiat 132 2000. On this model Fiat (UK) Ltd. have asked for all cars to come in with P6s, which make an inordinate contribution to the handling of this previously rather insipid design.
The Plus One part of their marketing must be derived from the idea of using a one inch bigger wheel in conjunction with a tyre that loses an inch in overall height (profile) to bring the rolling radius back to the same as would be offered by a conventional 80%, and over, aspect ratio radial. From a Pirelli viewpoint the Plus One is a rival to the Michelin TRX. There are major differences though. The TRX uses an odd wheel diameter, so calling for special wheels. Generally the Pirelli merely uses the next wheel size up: if the car has 12 in. rims (like Fiesta or some Escorts) then you would go onto 1310. diameter, and so on. There are the obvious differences in construction (pure steel bracing for Michelin, or the usual Pirelli nylon and steel) and profile.
I have driven the Granada S with TRX and the Fiat 132 on P6/Plus One. The Granada experience was but 40 odd miles (at speeds indicated up to 130 m.p.h.) while the Fiat was driven for hundreds of public road miles. The Michelin produces terrific cornering power without fuss: I did not unstick the Granada S.
The Fiat could be driven in most enthusiastic style, relying on the progressive breakaway of the Pirellis to produce some most enjoyable motoring from a car that I had previously regarded as a rather solid model of the “understeer is safest” school. In other words the Pirelli feels more conventional and ought to be slightly cheaper. At present the Plus One P6 is installed only as original equipment (more announcements are expected) but the Plus One idea will eventually spread so that the enthusiast can convert his car to the system. Based on the remarks made to me about the sporting looks and character of the tyre, I would expect the Ford RS Escorts to have Plus One tyres shortly. Perhaps as an option? Once the new Escorts have them, then a lot more could be interested: those with secondhand Mexitos, and so on.
The story of the P7 range is inextricably bound with competition. The sports department at Pirelli consists of 30 men, headed by Mario Mezzanote (the English translation of his surname leads to the nickname, “Mr. Midnight”) and assisted by Gianni Gariboldi. They have access to the 70,000 sq. metres of roads that comprise l’irelli’s remarkable Vizzola test track, but the real prove pneuntatica takes place in rallying. Pirelli have a fine record in the World Rally Championship: in all but one of the years since 1972 they have provided the rubber for the victorious team, the exception being 1973 with Renault-Alpine on Michelin. The remarkable Lancia Stratos has accounted for a hat trick of these WCR titles; it was on one of these fabulous hybrids that Pirelli launched the P7 in public.
The occasion was the 1976 Monte Carlo Rally Sandro Munari took his third win, but on the new tyres, which had contributed so much in a year noted for the one-pattern rule. Equally significant to the British teams was Walter Rohrl driving an Opel Kadett GT/E on the same covers, who snatched the touring car prize from a Dunlop-shod Roger Clark. So the squat new Pirellis really made a double impact.
In fact the P7 had its first taste of competion with Raphael Pinto, then driving a Fiat 125 Snyder Rallye within a Sicilian event. It took 18 months to develop the first drawings into the cover used on the Monte, but subsequently the P7 coding has been applied to tyres that cope with everything from smooth dry tarmac to flexible block 135/100 VR P7 that put the Lancia Stratos “up on stilts” for this year’s Safari Rally. The narrow P7s were used solely for forging through mud, a 175/80 P7 being reserved as cover for the majority of the Safari: normally the P7 carries a 205 mm. width and 60% low profile.
Despite the painstaking use of technology Pirelli still reckon the Safari as the one classic they have yet to win in the rallying calendar. P7s have also been produced for straightforward rain conditions (extremely effective on the World Championship Fiats last year), an intermediate wet, and a straightforward slick. At one stage the Stratos was involved in Group 5 racing, showing a very promising turn of speed, so it is obvious that Pirelli can make a good racing cover still (the Lancia engine was not in the Turbo Porsche league). The intriguing question is whether Ferrari ever tried Pirelli while testing Michelins and Goodyear for F1 in 1978. Since Ferrari has chosen Michelin it seems unlikely that we will ever know… but if Pirelli did join the F1 fight how long could Dunlop resist the challenge? Presumably Pirelli would only be really interested in an Italian team (though both Toyota and Opel are happy in the rallying World to use Pirelli) and that means a very tough competition even to get onto the car that represents the pride of a nation.
The story of the P7 goes beyond competion though. The Porsche Turbo comes on a road version of the tyre which company people say “little changed from the competition version. Ride quality and quietness are good in the rally tyres and remain as outstanding properties of the tyres fitted on these high performance cars”.
The Porsche 928, Lamborghini Countach and Urraco, all have now fitted the P7 as the standard equipment. In the Countach’s case the low profile is taken down to an amazing 35% easily mistaken for a formula racing cover. As ever the surprise is Ferrari, neither company giving a press reason for the omission, though Ferrari himself has always spoken most warmly of Michelin efforts, on and off the track. The writer can vouch for the fact that the Pirelli P7 (assesed on a rallying Stratos or the two road-going Porsches) does provide an extraordinary degree of civilised road manners with high grip predictable handling. One would expect high road noise and a certain amount of wandering over white lines and other ridges on such wide covers, but Porsche and Pirelli engineers really do seem to have found the answers: comments from fortunate readers would be appreciated.
I have not attempted to explore the technical nuances of the Pirelli tyre range in this artie but I hope that what we have been able provide shows why Pirelli is such a common name on every-day production cars and in competition. – J.W.