Triumph TR4
Triumph TR4 Tyres
Original equipment tyres for a TR4 and TR4 A were 590-15 Crossply tires. However for modern roads fitting your TR4 and TR4A with radial tyres is arguably more suitable and today the majority of people do tend to fit radial tyres to their TR4.
Radial TR4 Tires
Longstone Tyres recommend fitting the 165HR15 Michelin XAS as the best tire for a TR4 and TR4 A. In 1968 tyre manufacturers developed wider more modern low profile tires, Triumph continued to fit 165HR15 Michelin XAS to a TR6 because these sports cars handle better on a thin progressive tyres. Another extremely good option for these cars would be the 165HR15 PIRELLI CINTURATO ™ CA67 as these are genuine period tyres developed in the 50's and are an exceptional sports car tyre perfectly suited to cars like the TR4 and TR4A and of course they look fantastic.
Often with the TR4, TR4A and other cars of this period people want to fit wider tyres. Longstone don't encourage this unless you do other upgrades to counteract the derogatory effect that the wider tyres will have on the handling of your TR4 or TR4A. However if you want a wider tyre, then the best option would be the 185/70WR15 PIRELLI CINTURATO ™ CN36 shown in this picture of a TR6. Because the CN36 is a period tyre with a carcase designed for non power steering cars like Triumph TR4, they are designed to handle in a progressive manner, which will suit your car better than a modern tyre that is developed to compliment a totally different car design.
History of the Triumph TR4
Built between 1961-1965 the Triumph TR4 was a two seater sports car with iconic Michelotti styling, with 40,253 being made. A well renowned car, the TR4 and TR4A had a number of successes racing on American soil (three TR4As coming 1st, 2nd & 3rd in the 1966 Sebring 12 hour race) as well as rallying around Europe. Both models used an increased bore 2138cc engine, the main difference between the TR4 and TR4A is that the TR4A was built on a new chassis and had a more complex rear suspension with the aim of providing a more comfortable ride.