Pirelli Cinturato

The Pirelli Cinturato is a Pirelli-developed car tyre that was the first example of a wrap-around radial tyre structure. It was used to good effect in motorsport, and most modern tyres are based upon the design. The five-times Formula One World Champion Juan Manuel Fangio called the Pirelli Cinturato "Extraordinary"[1] and raced on it many times in the remainder of his career.

History
A comparison between a standard tyre of the time and the Pirelli Cinturato

First developed in 1952 under the name Pirelli Cintura, taking the name Cinturato in 1963, the tyre was composed of two or three carcass plies of cords laid at an angle of 90 degrees to the beads, and a belt of several plies laid circumferentially under the tread. Without a belt, the 90-degree plies would produce a casing which would greatly increase its sectional height on inflation. The belt, being inextensible, prevented the casing increasing in height when inflated, and the inflated tyre maintained almost the same dimensions as in the mould in which it went through vulcanisation. The belt was kept under tension, and the tread retained its flatter profile even when the tyre was inflated.[2]

The Pirelli Cinturato may be compared to a wheel in which the rim is attached to the hub by means of fine spokes. The tread and belt are in effect the rim; the 90-degree or radial cord plies are the spokes; and the bead is the hub. The inextensible belt and the radial casing cords were the combined factors which gave the Cinturato tyre its special properties.[3] The different geometric arrangement of the Cinturato carcass resulted in greater deformation (bulging) in the area of the tyre section which is under load, as opposed to previous radial tyres of the period. This caused no disadvantage and did not result in greater tyre casing fatigue. Rather than having the dynamic wave form behind the road contact area, it instead formed on the side wall, increasing stability whilst also allowing the heat generated by cornering and braking to be easily dispersed.[4]

During the 1950s, 1960s and 1970s the Pirelli Cinturato was the original equipment tyre for many exotic Italian cars including Lamborghini, Lancia, Alfa Romeo, Maserati, Ferrari as well as for cars produced by other manufacturers worldwide, including MG, Rover Group, Volvo and Lotus Cars. Many other international car manufacturers such as Jaguar and Aston Martin that were still fitting crossply tyres as standard equipment fitted Pirelli Cinturato as their radial upgrade for customers that could afford it. By the end of 1968 Pirelli was exporting or directly manufacturing the Cinturato to or in as many as 137 countries worldwide.[5] In 2014, the Pirelli Cinturato P7 was developed, derived from F1 technology, which had permitted Valtteri Bottas to drive his F1 car at a maximum speed of 316 km/h in fog.[6]

The first Cinturato tread pattern was the CA67, still made today in the sizes 165HR14, 155HR15, 165HR15, 185VR15 & 185VR16. Immediately recognisable as it was fitted to so many desirable cars such as the 250 GT Ferrari and Maserati 3500GT. It was also the tread pattern that Jaguar fitted to its XK150, series 1 E type and MK2 Saloons (Jaguar never fitted Pirelli tyres as original equipment on any model XK, E type nor Mark 2 saloons, but were only offered as aftermarket replacements) and that Aston Martin fitted to their DB2, DB3, DB4, DB5 & DB6 if a customer specified they required radial tyres. The Cinturato CA67 is also famously the tyre that Roger Moore had fitted to his Volvo P1800 in the series The Saint.[7]

In 1964 Pirelli developed a new extra large high performance tyre with a 205 section and a new tread pattern that was designated CN72 HS (HS standing for High Speed). This new tyre again took the world of sportscars by storm and kept the Cinturato as the tyre of choice for sports cars such as Ferrari 330 GT 2+2, Iso Grifo, Lamborghini Miura and Maserati Ghibli. Once again Aston Martin also offered them as a radial alternative for their DBS.

Towards the end of 1968 the new tyre technology was low profile tyres. Pirelli were hot on the tail with their new CN36 which came out in 1969. The CN36 had a striking tread pattern and was a favourite for the likes of the Porsche 911, Ford Escort & Ford Cortina. 1971 would see Pirelli’s introduction of another high speed (HS) tyre with their CN12 Cinturato HS. These tyres were rated to be able to withstand the exceptional power of the Lamborghini Miura SV, and today their 205/70VR15 Pirelli Cinturato tyre holds a W speed rating (170 mph).

Cars which can use Pirelli Cinturato[8]
Tyre Size Cars
165HR14 CA67 Alfa Romeo Alfetta, Giulia & Spider; Audi 100; Austin Cambridge & A60 Countryman; BMW 1800 & 2000; Citroen GS; Lancia Flavia & Fulvia; Mazda 1800; MG MGB; MG Magnette; Morris Oxford; Peugeot 504; Porsche 924; Riley 4/68 & 4/72; Rover 2200TC; Wolsley 16/60
185/70VR14 CA67 Low profile alternative of 165HR14 and can be fitted to Alfa Romeo Alfetta, Giulia & Spider; Audi 100; Austin Cambridge & A60 Countryman; BMW 1800 & 2000; Citroen GS; Lancia Flavia & Fulvia; Mazda 1800; MG MGB; MG Magnette; Morris Oxford; Peugeot 504; Porsche 924; Riley 4/68 & 4/72; Rover 2200TC; Wolsley 16/60
155HR15 CA67 Alfa Romeo Giulietta and Giulia; Lancia Flavia and Appia; Lotus Elite; MG MGA; Peugeot 403 and 404; Triumph TR2 and TR3; Volkswagen Beetle
165HR15 CA67 Alfa Romeo Giulietta Giardinetta; Austin Healey; Daimler SP250 Sport; Fiat 2300S Coupe; Gilbern; Lancia Flavia; MG MGA; MG MGC; MG TF; MG TD; MG YB; MG Magnette; Morgan 4/4; Morgan +4; Morris Oxford Traveller; Peugeot 403; Peugeot 404; Porsche 356; Porsche 912; Porsche 914; Porsche 911 (pre-1968); Triumph TR4; Triumph TR5; Triumph TR6; TVR Vixen; TVR Tuscan V6; VW Beetle; VW 1600; VW k70; VW 411; VW Karmann Ghia; Volvo Amazon; Volvo P1800
185VR15 CA67 Aston Martin DB4, DB5 and DB6; Jaguar E-type series 1 & 2 and Jaguar Mk1, Mk2 & S-type saloons; Daimler V8 saloon; Ferrari 250 GT and 250 GTE; Mercedes 220D; BMW 2600 and 3200; Citroen ID and DS; Morgan +8; Rover P4 and P5; Jensen CV8
185/70VR15 CN36 Austin-Healey; MGC; Porsche 911; Porsche 924; Porsche 944; Triumph TR4; Triumph TR5; Triumph TR6; Volvo 1800ES
215/60VR15 CN36 Porsche 911; Porsche 924; Porsche 944;
185VR16 CA67 Aston Martin 2-Litre Sports, Aston Martin DB2, Aston Martin DB2/4, Aston Martin DB Mark III, Aston Martin DB4, Aston Martin DB4 GT Zagato; Jaguar XK120, XK140, XK150 and C-Type; BMW 2500 and 375; 1950s and early 60s Maserati and Ferrari; Bristol up to the 409 in 1967; AC Ace; Triumph Gloria and Renown; Riley RM and Pathfinder; Lea Francis up to 1954; Daimler DB18
205VR15 CN72 AC 428; Aston Martin DB6 MkII; Aston Martin DBS; Bentley Type 1 (1966-1973); Ferrari 330 GT 2+2; Ferrari 500 Superfast; Ferrari 365 and Ferrari 365 GT 2+2; Bizzarrini Iso; Rivolta and Grifo; Lamborghini 350GT; Lamborghini 400GT; Lamborghini Islero; Lamborghini Miura and Lamborghini Espada, Maserati 4200 Quattroporte; Maserati Mistral 68; Maserati Mexico; Maserati Ghibli; Maserati Sebring; Rolls Royce Silver Shadow (1963-1973)
205/70VR15 CN12 Aston Martin DB4; Aston Martin DB5; Aston Martin DB6; Aston Martin MKII; Citroën SM; Daimler Sovereign; Daimler Double-Six; Ferrari 250; Jaguar XJ6; Jaguar XJ12; Jaguar XJS; Jaguar E-Type V12; Jensen Interceptor; Morgan Plus 8

References
  1. "Juan Manuel Fangio Pirelli Cinturato advert". Pirelli. Retrieved 27 January 2014.
  2. Pattern of Progress, p. 2.
  3. Pattern of Progress, p. 3.
  4. Pattern of Progress, p. 6.
  5. "History of the Pirelli Cinturato". Pirelli. Retrieved 27 January 2014.
  6. "Pirelli Cinturatto P7". VanzariAnvelope.net. Retrieved 2014-11-19.
  7. "Roger Moore with The Saint's Volvo P1800". Volvo. Retrieved 12 June 2015.
  8. "Pirelli Cinturato Fitment Guide". Cinturato.net. Retrieved 28 September 2015.

Bibliography
  • Pirelli (1964), Pattern of Progress Pirelli Cinturato, H. Hacker Ltd.
  • Pirelli (March 1964), Fitment and pressure table for Cinturato car tyres, Mears Caldwell Hacker Ltd.
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