Ralph M said:
When radials first came i Renault fitted them to I think it was the Renault 8 these were rear engine'd rear wheel drive
and the rear tires wore out first, people then fitted cheaper cross ply's the driver getting better front end grip drove faster than
the rears could handle and the car would swap ends sometimes disastrously, the car got a reputation for evil handling
but it was more to do with cheap skate drivers fitting a bad mix of tires.
This part is true. But it also had some part to do with "Trailing Throttle Over-steer" (TTOS) when the driver lets off the gas in a corner while on the brakes and the rear engine weight trys to keep up speed and swaps ends. Porsche 911's are prone to this as were VW Bugs and Van/Wagons. Porsche was one of the first manufactures that solved this problem, well about 80% of it, by staggering tire sizes front to rear. By adding 20mm or (MUCH) more in tire width in the rear made the rear have more bite in TTOS conditions. I can use TTOS in cornering a high performance frontwheel drive car at will by snapping off the throttle in a corner causing the front wheels to slow down and the rear starts to come around then countersteer and nail the gas to do a drift around the corner.
On a car/truck/UTE I would never put radials in the front and same sized Bias plys in the rear. Its really not a good idea to put radials in front and Bias in the rear period!!!
But I have tried like 205/70 SR 15 in front and 255/60 B
15 in the rear and they seemed to have the same amount of grip in the rain. Understanding stagger and plus sizing helps.
I say it again, Its really not a good idea to put radials in front and Bias in the rear period!!!