Defective Stock Pirelli PZN?

Please read the complete post before jumping to conclusions and commenting on my driving skills and my intellect for comparing A/S to Summer tyres, thank you.

TL DR: Stock tyres slipped so much even normal driving set off ABS and TC. New tyres don't set off TC even at 60% throttle in 1st gear. Old tyres defective?


I ordered my '15 Mustang GT Premium MT (Premier + 3.55 rear diff + some bits of Performance Pack, the only dealer in my country allows just that one spec) in April 2015, delivered on 3 August 2015 and it came with 255/40 R19 Pirelli P Zero Nero All Seasons.

From the beginning, I felt there was something wrong with my car or the tyres but suppressed those thoughts. When I would get on the gas in 1st, 2nd, 3rd or even 4th gear the back end would slide out and I'd be fighting the traction control. I switched to Sport+ last year and had to fight it less and did the corrections myself rather than fighting that stupid computer that kicks in too late and too hard.

I've driven manual transmissions my whole life, driven 400,000+ km (~250k miles) but I never owned a V8 RWD (Corollas, Subies, etc.) so I chalked it up to my inexperience. Try to accelerate hard, nope, spinning my wheels. Roll on to the throttle gently, nope going sideways in 3rd gear above 4.5k rpm. Couldn't manage above 0.48g on the TrackApps no matter what I did. I thought I'm a horrible driver and left it at that. At least I have good spatial awareness and have never crashed into anyone, I thought.


I changed to Michelin Pilot Sport 4 three days ago (the PS4S is not available in this size my country and neither was the MPSS - but maybe that one was out of stock, the dealers here don't really know their jobs. The tyre change supervisor on the floor didn't know what TPMS is, so yeah) and Oh MY GOD.

I will take it gentle for the next 500 miles but I can feel the difference SO STRONGLY, I'm not comparing to how my tyres felt at the end of their life. I'm comparing to how I felt when the car was new. I gave it 30% throttle, 40% throttle, 60% throttle, no traction control light! I really felt the acceleration of the Mustang even at half-throttle. My tail-end doesn't break lose, ABS doesn't kick in under slightly harder than normal braking!

Note: It never goes below 20 deg. C (70 deg. F) in the winter here and goes above 46 deg. C (115 deg. F) in the summer sometimes and stays nearby for most of it.

Maybe I'm not a horrible driver after all, maybe it was the tyres?! Has anyone else experienced it? Alignment and balancing were done every year. Treadwear was normal and even. The rear ones were down to about 10% tread left (before it reached the Tread Wear Indicator) and the front ones had above 30-40%. The old tyres had 46,000 kilometres on them when replaced (29k miles)

Going from A/S to Summer or from Pirelli to Michelin (I think the PS4 are even a cheaper tyre than the stock PZN) should not make this big of a difference! Do you think I had a defective set of tyres? What is wrong in my reasoning here?

Thanks for reading.

The PZero Nero’s are nobody’s favorite tire. They have a reputation for sucking. I don’t think they were defective, just not a good tire for a muscle car. Your story isn’t all that surprising. It’s a pretty old design and tire tech is always changing and improving every year. I understand yours were not grippy from the start, but years of use and 30k miles make a bad tire a lot worse because every time you get a tire warm from driving and let it cool down (a heat cycle), the polymers in the rubber align and the tire gets a little bit harder. All tires do this, but a tire that starts out not so great can be terrible by the end of it’s life. Even moving from old hard MPSS tires to new MP4S tires was a dramatic change on my car because old MPSS tires had hardened up over the years.

Congrats on the new rubber, now you can enjoy the car so much more!

I agree they were quite bad from the beginning but near the end they got so bad that I could hold a silent drift around a turn for like 5-7 seconds with 1/3rd throttle! That's after rolling on it!

They're just bad tires man. I had the same problem before swapping. Do a 2nd gear stab...tail kicks out, 3rd gear roll-on tail kicks out. Eventually when I went and bought winter tires THOSE had better grip than the PZN. When I finally got summer tires, I could finally feel like I'm driving with confidence. Ford really snoozed on these because they do not belong on a car that makes 400HP+...or hell even 300HP+. So in conclusion, yes they're bad.