Over the last few years Pirelli have upped their game when it comes to suppling top quality radial tires for classic cars. Their range has recently expanded to include some important tires for people who want their classic Porsche to drive at it’s best and at the same time look the way it would have done when it was first produced. Most of these relevant Porsche tires have now been homologated by Porsche themselves and now qualify to have the N4 designation.
The 914, 912 and early 911 have a choice of tires. Pirelli Still make the 165HR15 Cinturato using the CA67 tread pattern that came out in the early ‘50s and carried on through to the ‘80s. For the early look they are perfect, and the perfect radial tire for a 356 as well. However Pirelli in conjunction with Porsche have N4 homologated a new 165VR15 Cinturato CN36 N4, which has the CN36 tread pattern, of 1968, that was strongly associated with Porsche from the end of the ‘60s through the ‘70s.
In the Autumn of 1967 Porsche increased the rim width of their early 911 wheels from 4.5” to 5.5” Fuch wheels, and continued to fit 165HR15 Pirelli Cinturato (among other brands) until September 1968, when they moved onto the new low profile tires 185/70VR15 on 6” wide rims. It was at this point that Pirelli introduced their new low profile tire range Cinturato CN36 and the early 911 fitted 185/70VR15 PIRELLI CINTURATO CN36. This tire went into production again in January 2015 and then attained the N4 Classic Porsche homologation in May 2016.
It wasn’t what they fitted originally, however, if you have fitted wider wheels on your classic 356C, 912 or 914 then Porsche also recommend fitting the 185/70WR15 CN36 N4 and they are also the correct tire for your early 924.
In 1972 Porsche started to fit wider rear wheels on their 911 Carrera and the classic 911 RS models which fitted the extra wide 215/60WR15 Cinturato CN36 N4 which was reintroduced by Pirelli to their range of classic Porsche tires at the same time that the 185/70WR15 CN36 attained it’s N4 Porsche homologation. Throughout the ‘70s this fitment became common option on 911 cars, and became standard with the SC 911 Models from 1977 until August 1986 where the front tire became a 195/65R15. At this point Pirelli’s P6000 range of tires would be more suitable, and the true historic range of tyres becomes less relevant.
There is one other introduction from Pirelli that is an exciting move forward for people that want their vintage Porsche to handle and look the way they should; Pirelli have now reintroduced 2 sizes from the famous Cinturato P7 range of tyres. Pirelli’s P7 range introduced seriously low profile tires, in the ‘70s; for car manufacturers like Porsche and of course famously the widest tyre on any production car at the time, the 345/35VR15 Cinturato P7 for the time honoured Lamborghini super chic Countach. There is hope that in the future that tire will be reintroduced along with a 285/45VR15 because they are both extra wide rear tire options for racing and Rally early 911’s with extra wide (up to 14”) rear wheels. However for now Pirelli just make the 205/50YR15 & 225/50YR15 Cinturato P7 tires that were original equipment on Some of the sports models of the mid ‘70s period such as the 3.0 Turbo, 930, 3.0 Carrera and they were offered as an option to early 911’s on 7” and 8” rims.
It is the miss conception of so many classic car owners, including many early Porsche owners, that putting more modern tire designs on their vintage 911, 912, 356, 924 or 930 will improve them. This is not the case, which is why Porsche are recommending these genuine period tires for their cars.
Classic cars handle at their best fitted with a tire that is developed to flatter the attributes that a particular car has to offer. Heavy modern cars have adverse camber, caster and clever power steering. The combination of these features means that modern cars are equipped to be complimented by modern square shouldered tire carcass designs, with tire widths that are suited to these heavier cars. They go together like cheese and crackers. An early Porsche 911 is suited to a thinner tire, combined with it’s rounded shoulders which maintains the progressive handling that keeps these light weight rear wheel drive cars so enjoyable to drive.
The question of whether these current Cinturato tires are exactly the same as the original tires is often raised. It is not legally possible to make a tire that is exactly the same as it was in the ‘70s because some of the materials and chemicals used to build these vintage tires are no longer allowed. Effectually you use the road surface to scrub your tire into a fine powder and put that powdered rubber into our rivers, and the fish just don’t like it. We have the ability to make greener rubber compounds that work better than they did in the ‘70s, without effecting our environment so badly, and so we should.
Today’s production of Porsche homologated N4 Classic tires are made with bang up to date compounds, developed to give maximum grip from a small foot print. This modern compound is presented to the road on a period carcass, designed with rounded shoulders developed in period to compliment lightweight rear wheel drive sports cars, like a vintage Porsche 911, so they don’t let go suddenly as the car rolls, using modern quality control systems so that every tire is just as brilliant as the last one.
Oh yes, and look cool!