Radial Tuned Suspension

24. December 2015 10:56 by Rare Spares in Rare Spares  //  Tags: , , , , , , ,   //   Comments (0)

Ask an Australian car lover who invented RTS (Radial Tuned Suspension) and the answer will be Holden. However, ask an American car lover who invented it and they would likely say Pontiac. In truth, the facts are a little hazy.

In America, Radial Tuned Suspension started in the mid-70s when radial tyres were becoming more of a standard feature on GM cars, and Pontiac tuned the spring rates and shock valving to better match the type of tyres going onto their new cars.

In Australia, the first cars to get RTS were the Holden HZ Kingswood SL, Premier, Wagon and GTS. The HZ hit our roads on October 1977, so from that perspective, the victory goes to our friends on the other side of the Pacific. RTS, according to Holden was “an important new design which integrates all suspension components into one finely tuned system.”

Assistant Chief Engineer Peter Hanenberger from GM Germany headed up the RTS program in Australia and explained RTS was designed to “reduce vehicle roll when cornering, improve straight ahead stability and improve vehicle handling and load carrying ability on all types of road surfaces.”

Effectively it was designed to match all the suspension components because Holden was also moving from bias ply tyres to steel belted radial tyres. Changes included wider wheel rims, revised body mountings as well as the chassis. Front and rear stabiliser bars helped control lean, the four coil springs were deeper, front suspension control arms were redesigned and moved, control arm bushings were reengineered and new, larger diameter shock absorbers were carefully tuned to match the RTS system. All this was designed to create Holden’s claim of “exceptional road holding”.

RTS was so important to Holden, it ran an advertising campaign. It showed a Kingswood SL against a BMW in an evasive manoeuvre display to demonstrate how well it compared against one of the best handling European sedans. A Holden Premier was then pitted against a Mercedes Benz on a bumpy and undulating road, which showed our home grown hero had just as good a ”smooth, flat ride” as its more prestigious and expensive competition.

With the Europeans easily dispatched, the advertisement then turned to Holden’s domestic nemesis. (No prizes for guessing who that might be!) This involved a typical highway exit situation where the RTS equipped Kingswood easily out manoeuvred the competition around a tight bend in wet conditions, showing how predictable the Kingswood SL corners as compared with the other car. That other car, without RTS, was of course unable to follow the Holden at the same speed.

So there you have it. RTS was designed as “a system, through a sophisticated program of engineering research, designed for Australian conditions, so as to enjoy confident, relaxed driving, mile after mile.” Of course, RTS may have been cutting edge at the time, but suspension systems have certainly moved on and will continue to evolve. It’s certainly interesting to see the progress that’s been made over the last four decades of automobile development, that’s for sure.