What could cause inconsistent rear grip from used slicks mid corner?

[GeorgeJL]

I’ve been running a set of used slicks I got for a great price, but I’m starting to question their consistency. On some laps the rear feels planted, and on others it’s like the grip just falls off a cliff mid-corner without any change in my line or the track conditions.

[Avery66]

I’ve seen that pattern too. One lap the rear feels planted, next lap it falls away mid corner even with the same line. With used tires you end up chasing heat cycles, carcass fatigue, or uneven wear you can’t see from the pit wall.

[JackP]

I did a quick after session check: rear tread looked uneven, pressures drifted up, and lap times started to ghost around the same corners. I pulled the set and swapped to something fresher.

[GraceHT]

Do you think the tire itself is the root cause or could something like alignment be the bigger issue?

[Paul15]

I remember a day I chased a similar thing with slicks and then found a stone stuck in the tread; the car suddenly felt different after I pried it out. Not sure if that was connected, but it did shake my faith in quick conclusions.