The styling of the body of the TR6 was done by Karmann of Germany. Triumph Motor Cars had a limited budget for the development of the TR6, and while the TR6 looked drastically different from the previous body style of the TR4/TR4A/TR250/TR5 cars, the same chassis, engines, running gear, doors, windscreen and much of the body tub were taken directly from the TR250/TR5 models. The new removable hardtop for the TR6 was designed in-house by Triumph, and was available as an option.[5]

Construction of the TR6 was traditional body-on-frame with four-wheel independent suspension, front disc brakes and rear drum brakes.

All TR6s were powered by Triumph's 2.5-litre straight-6 engine.

The TR6 featured a four-speed manual transmission. An electrically switched overdrivemade by Laycock de Normanville was available as an option. On early cars the "A-type" model overdrive was used and was able to be activated on second, third, and fourth gears and provided a 22% gear ratio reduction. Later TR6s had a "J-type" model overdrive able to be activated only on third and fourth gears but with a 28% gear ratio reduction.