Crazy oversteer / wheelspin with Michelin Pilot Super Sport
 

I bought the car new and after 1000Km I changed the tires to the supposedly much grippier Michelin Pilot Super Sport, 215/45-17, on stock wheels. The car is manual and not modified. Under braking the tires are amazing, but I break traction under light/medium throttle at very moderate speeds in a corner, so I get oversteer constantly. 3000RPM, 2nd gear, 40Km/h, if I gently accelerate out of a corner, the back slides out.

Do the MPSSs need to be warmed up before they'll grip on the road? I have them inflated to 37psi. I haven't tracked them so it's not like they were heat cycled. Baffled...

Drop those pressures, try 32-33PSI
Could be alignment too. But MPSS are not super sticky tires.

I think the max psi for this car is supposed to be 35

Recommended tire pressure is 35 psi, no reason to run any different pressure. Certainly lowering tire pressure will not improve tire grip.

How green are your tires? Check the DOT manufacture date for tire age (fresher is better but they will be greener to begin with) and how many miles on these tires?

Green tires are not very grippy no matter what make or model they are. Mould release needs to be scuffed off and the tread surface scuffed up. Heat cycling isn't a big factor with street rubber but it will make some difference especially with these ultra high performance tires.


One more thing is the factory alignment often isn't any good. Mine was out of spec from the factory and required camber bolts to reach correct spec. Subaru has a part number for camber bolts for the rear LCA so that tells you something. Probably an Impreza part number.

Put 2,000 miles on the new tires and then check back with us.

check your alignment. or maybe it's your driving style possibly, too abrupt with throttle and/or steering? just a guess...

PSS can't compete with r-compounds, but they are imo, one of the best street tires. i had them on my previous e92 and they were awesome.

Drop your tire pressure to whatever is recommend on the door sill and drive smoother.

Something is up. I have the same size MPSS's on stock rims and my back end would definitely not slip as much. Took about a week or two to wear them in a bit, but it was still a noticeable change right from the shop.

I've had my MPSS's for 10k+ miles and get the same thing fairly often. They break loose just as easily as the primacies did before they warm up. After warm up (e.g. after a 2+ hour drive), I will still get them to break loose extremely easily at a very specific corner at my destination (not in an intentional way). Breaking them in did not help as far as I can tell (in regards to the above). I, however, could tell a serious difference in grip in normal day-to-day driving vs. the primacies.

never broke loose even on my stock primacies...:sigh:
yeah like they said..probably to do with your driving style being too aggressive.

Lowering pressure will absolutely increase grip (to a point), but how far you can drop it will depend on many factors.

Yeah um no it absolutely does increase grip to a point, hence why I lower the pressure in my tires for drag racing. It really depends on the driving you do. That said running 2psi over the recommended pressure probably isn't helping you.

Are these corners 90* corners? lol

Camber bolts for the real eh? Do you have a p/n?

Something is definitely wrong here:

1) You shouldn't be getting oversteer "gently accelerating" out of a corner at 3000 RPM in 2nd gear on the street.

2) I would say be more smooth with your inputs, but if these issues only started once you switched to MPSS, it sounds more like mechanical/equipment problems. Or perhaps moisture/sand on the road surface.

3) Until you've figured out the issue, I'd recommend leaving TC on. While testing, keep an eye on the yellow TC light on your dash. If it starts blinking, you're getting wheelspin. It's a safer way of testing on the street without getting actual oversteer.

4) In any event, MPSS are stickier than stock Primacys/Turanzas, so if you suddenly have crazy wheelspin or oversteer issues after switching, something is off.