Triumph TR4A was built between 1965 and 1968 by the Triumph Motor Company in the United Kingdom.
The TR4A was an evolution of the TR4, updated with a new chassis. It was hoped the new, but more complex independent rear suspension would address the buying publics' desire for more comfortable riding sports cars. This version has an "IRS" badge on the rear. It's estimated 75% of TR4A were built with IRS.
But, Triumph was again hedging their bets. In response to dealer requests, approximately 25% of TR4A were produced with a solid rear axle (also called a live axle), similar to the earlier TR4. This might also have been a nod to the popularity of the cars as production racers, since the solid axle design was much more easily and less expensively prepared for competition work.
The new suspension did eventually prove itself with the buying public and in racing, with three TR4A IRS posting a team win and finishing 1st, 2nd and 3rd in class at the Sebring 12 Hour race of 1966.
In 1965, the TR4A IRS sold in the United Kingdom for approximately £968, with wire wheels being another £36, overdrive £51, heater £13 and seat belts £4 each.
Buyers Guide Triumph TR4, TR4A & TR5 featured in Practical Classics February 2003 – available from our sister site Bookbase. Click here to view.