terrible advice.

Holy cow - how are you guys getting 3,000-4,000 miles out of bike tires? That's approaching motorcycle tire life! You must weigh 120 lbs. and ride on linoleum I've never gotten more than 1500 miles out of tires and that was on some Michelin carbons that I was careful to switch front/back every 300 miles or so.

Assuming they haven't met a premature demise through big cuts, I replace mine when they're squared off enough to adversely affect cornering. That's typically long before threads start to show.

Mostly using them until the cords show (2/3 of their life can remain when they square of) and running longer lasting tires.

I was getting ~4500 miles at 180+ pounds from Continental Gatorskins and GP4000s.

At 137 I had tread left on my last GP4000SII at 6466 miles, but cut cords on road debris before getting to the center of that tootsie pop.

The current one has 3302 rear miles after 8578 in front.

Given how compliant rubber is I expect your cornering problems are coming from the placebo effect.

You'll never convince me I can somehow "will" squared off tires to handle as well in adverse conditions like wet, gritty, oily turns.

I buy ~$25 training tires (currently liking the Forte AMR+) and ride them until the rear tire is looking very square. This takes about 4k miles. Then I replace both tires because I'm vain and want matching tires. Also $50 is not a lot for 4k miles, I can afford it.

I bought a set of Conti GP4000s a few years ago. I couldn't detect a significant handling difference and I had two ride ending cuts within 3k miles. I promptly went back to the cheaper/tougher tires.