oh they are REALLY bad.
First I'm sure you have read about peoples experience with them. it seems every time some classic car spins out on the highway a cooper tire is involved.
personal experience: you don't know something is bad until you compare to something better.
I had Vipers on my car back in 2005 that came with the car. I had a blow out with these tires because they sat for so long since the late 1990s that the belts shifted and the tires fell apart. I had literally no experience with these tires maybe 200 miles and they were falling apart from the first day i tried to drive the car.
I took my car to a alignment shop and they had never seen tires so bad, on their recommendation they installed cooper tires.
ok so no big deal i have new tires lets drive the car. I noticed the car was harder to drive in maintaining control it felt squirly over 45mph. I chalked that up to not having really driven the car and other issues that took until 2009 to iron out on my car so i had these tires for 4 years at this point.
driving in the rain was BEYOND scary, almost no rear traction when wet the tires had maybe 5000 miles on them. i kept them and at the same time was doing research on a better tire.
over the years i had a couple of close calls with the coopers, loosing control on wet leaves in the fall and nearly hitting a guard rail. really Squirly handling in all conditions that resulted in me making a ton of changes and modification to the suspension thinking maybe my frame was out of wack.
i added a larger front sway, a rear addco sway(big improvement), i changed out the spring perch from oem to roller. changed from poly to oem rubber type bushings.
tried different castor and camber settings over the years as well.
6 more years on these tires went by,
then last summer 2015 i decided i really wanted some new tires the coopers were over the 5 year life of a tire i had just replaced my transmission in the car and i had installed a new high stall converter, what was happening was i was now doing burnouts all the time even when i didn't want to.
thus it was time i went to the tire place and after looking at the options the BFG was the best tire i could afford. off came the coppers and the BFGs went on.
IT WAS NIGHT AND DAY, the car felt planted for the first time, no funky handling i was doing like 95mph on the highway no problem, didn't feel like the car wanted to skid off the highway any more. no more burn out everytime i touched the peddle it was obvious the BFGs had a WAY WAY higher grip then the coopers ever had. for the first time i felt pretty safe driving the car more then ever before. when the road is damp i don't freak out any more really treating it like i was on a ice sheet with the coopers.
i can not speak for others but for me the difference was beyond a feeling this was a fully documented improvement. i cursed the day i let them put the coopers on my car in 2005.
