Early Handling Problems and Solutions

The rear-bias was always a problem to 911's handling. Any tail-heavy cars have a tendency to oversteer. If such oversteer is not adequately suppressed, lost of control may occur. Although there were some racing car being more tail-heavy and more powerful yet had fabulous handling, say, the 1000 hp 917 Can-Am race car which carried near 70% weight at the rear, the production 911 lacked their racing-spec aerodynamic aid as well as racing tyres - the original 911 rode on 165 tyres with 4.5 in rims only !

To solve the problem, the suspension setup, that is, toe-in, camber, castor etc, should be accurately tuned to optimise the handling ability. However, in production line, such strict tolerances were found to be impossible to be implemented. Therefore the following corrective actions were taken :

1. The earliest makeshift solution was to add weight to the front end. Two 11 kg cast iron weights were added to the bumper of those 911s with unsatisfactory handling found, officially called "bumper reinforcement" because it was nothing to proud of. In fact many drivers of these 911 even didn't know about it !

2. Later, facility was added to adjust the upper location of the MacPherson strut, making it possible to adjust both castor and camber to the very close tolerances. As a result, "bumper reinforcement" was dropped.

3. In 1969, wheelbase was extended by 2.3 inches by moving the rear axle rearward. At nearly the same time, wider tyres were adopted, wheel rims widened to 5.5 in and then 6 in. These changes effectively improved its handling a lot.

4. In the following years, tyres were continuously widened, from 165 of the original car to 205 front and 245 rear of the 993. Turbo 993 even adopted 225 and 285 tyres. (note that rear tyres were wider than front) Lost of rear end became very difficult as a result.

5. Aerodynamic also improved. In 1972, "Duck tail" rear spoiler was introduced in the 911 RS 2.7. It reduced the rear aerodynamic lift by as much as 75%, thus greatly improved high speed stability. One year later, an even bigger "whale tail" rear spoiler appeared in the RS 3.0, then spreaded to all other production 911s in later years, completely eliminated rear lift

In its 34 years' history, Porsche progressively reduced the oversteer manner and eventually built mild understeer into the 911. The car became better controlled, easier to drive quickly but some found less fun than the earlier 911s. However, compare with 996, any 911s still had far more oversteer as well as the fun of challenge.

Porsche Classic Models

Porsche Classic Models

The History of Porsche Cars through its generational changes. A must have ebook for any Porsche fanatic, this ebook is a reference book for Porsche enthusiasts. Discover all there is to know about the greatest Porsches ever made. All models are fully described and illustrated providing a definitive production history plus an accurate guide to original specs and equipment.

Get My Free Ebook


  • lauri
    What is the solution to the 2005 porsche 911's handling?
    17 days ago

Post a comment