At the beginning of 1977 there was great expectation caused by the 6-wheeled Tyrrell P34 and there were rumors of new models that included Ferrari.
On Thursday, March 10, 1977, Niki Lauda had a test scheduled with the Ferrari 312T2 at the Fiorano circuit and those present were asked not to take photos. Lauda would go out to tour with the Ferrari "six wheels" which he codenamed 312 "T6", although not officially. Strictly speaking it was not a six-wheeled car like the Tyrrell or the March, but rather a car with four wheels and six tires, that is, a car with dual rear tires on the single rear axle.
It was even suggested that the Ferrari could present a differential between the tires on each side in such a way that the inner one rotated at a lower speed than the outer one when going through the curves. It would certainly be an advantageous item but obviously complicated, and with dual wheels on its rear axle, exceeded the minimum regulatory width There were even those who went further by saying that they would probably replace the transverse box with a longitudinal one, something totally meaningless since it implied a profound reform, it would be a totally new car and not a modified T2, which it clearly was.

Further tests were carried out in Nardo by Lauda, but the results were not encouraging:
• High resistance to movement due to their considerable diameter and width.
• Important radial deformations at high speeds such that the effective contact patch with the asphalt suffered a great reduction and therefore the driving capacity also decreased.
• Excessive lateral deformation of the tires when cornering due to the flexibility of the rubber and the work of the suspensions. At the time it was estimated that, even with the most developed suspensions of the time, in high-speed corners the contact patch was reduced to 30 or 35%.

The last two drawbacks were the ones that most concerned the designer Mauro Forghieri at the time, and in an effort to deal with them he resorted to "splitting" the rear tires on the same wheel. In this way, the use of two tires with a reduced section and much smaller diameter than the conventional ones allowed not only to transmit the 500 CV to the ground but also offered, prima facie, several advantages.
The tests continued this time with Carlos Reutemann, second Ferrari driver, on March 21 at Fiorano, who noticed rear suspension problems just after the tests began. After 12 laps, he skidded and hit a guard rail. In the first instance, Ferrari blamed a driver error, but later the design problem and breakage of the rear suspension was confirmed.

The tests continued with Lauda at the wheel, but the Austrian never managed to equal the records achieved with the T2. It was becoming clear that the rear suspension design was not bearing fruit and the "T6" began to be relegated in the tests to continue with the development of the T2. Finally in May Ferrari announced that it was leaving the project aside.

The Chronicle