One of the discussions about handling in one of the F1 threads gave me flashbacks to a weird set of tires I had years ago on an Infiniti G20 (Nissan Primera for the Brits) back in 2002.
Up to that point I had had several different tires on the car: 195/60-14 Michelin XGT (stock tire), 205/50-15 Dunlop D40m2 (BBS wheels), some cheap Hankooks that replaced the Dunlops, and a set of Pirelli 190p snow tires on the stock wheels. None of them acted funny in any manner, and all performed as expected.
I needed a new set of tires, and since I was moving to less snowy climate, and I wanted to save some money, I decided to replace the snow tires on stock wheels with touring/performance tires. I don't remember the exact model, but it was a budget tire from Yokohama.
As soon as I left the shop, I noticed they had a peculiar behavior. At initial turn-in (imagine navigating a 90° turn along the access roads of a shopping center at 20 mph) nothing happened. I turned the wheel, and the car still went straight. In fact, I'm pretty sure I tried to correct this by turning the wheel even more. Then, after a delay (half second?) the car would turn. It was almost like there was understeer, but it wasn't technically understeer, as there was no skidding.
But that's just the front tires. The rear tires had basically the same behavior as the front tires: the front of the car is now starting to turn, but the rear tires are wanting to continue to go straight, in the direction the rear wheels had been pointing. Which meant it felt like oversteer. Then, after a half second (?) the rear tires would decide to align themselves with their wheels, and the feeling of oversteer would go away.
So initial understeer followed by oversteer, at 20 mph in a parking lot, all at levels well below the tires' friction circle. That behavior remained for the entire time I owned those tires.
I eventually had to adjust my driving style to the tires (it was probably the MCL36 thread that gave me flashbacks to these tires), but after 4 months of weird driving, I replaced them with a new set of Michelin XGTs, and everything was back to normal. No other car or minivan I've driven, before or since, had that peculiar behavior.
Whatever was going on with those tires, my hunch is that it had something to do with sidewall stiffness and slip angle, but I'm kinda shooting in the dark. Any ideas?