The Triumph TR4 was introduced in 1961 and succeeded the TR2 and TR3. It was based on the chassis and drivetrain of the previous TR sports cars, but with a modern Michelotti styled body. 40,253 cars were built during production years. The TR4 proved very successful and continued the rugged, "hairy-chested" image that the previous TRs had enjoyed.
The new TR4 body style did away with the classical cutaway door design of the previous TRs to allow for wind-down (roll-up) windows (in place of less convenient side-curtains), and the angular rear allowed a boot (trunk) with considerable capacity for a sports car.
In 1965, the TR4A with IRS (Independent Rear Suspension) superseded the TR4. Apart from the rear suspension, which used trailing arms and a differential bolted to the redesigned chassis frame and a number of small styling changes and refinements, the two models appear nearly identical.