2018 Prius Four Touring 17" uneven tire wear

2018 Prius Four Touring, purchased used 22k miles. Bridgestone Ecopia Plus 215/45 X 17.

This question is for owners with the 17" tires. I understand there aren't very many Prius owners that purchased this upgrade, as it defeats the whole MPG ethic.

Car can drive at 80mph, tires very well balanced.

All four tires show "feathering", both inside and outside edges. Rears are bad enough that they make a rapid "drumming" sound between 54-65 mph, but no wheel hop, or balance issues. I've tried increasing psi to 45/43 f/r, then 40/38f/r, finally back to the suggested 33/32 f/r. (as expected, MPG increased dramatically with increased PSI, with minor comfort decrease).

Tires have plenty of tread left, and the "feathering" can't be seen, but can be felt on the surface.

Discount Tire inspected them, saying the uneven wear/drumming will only get worse. Reversing the direction of the tires wouldn't change anything.

QUESTION: What possibly caused the uneven wear? Underinflation? Frequent rapid cornering? Records show tires were (supposedly) rotated approx. every 5k miles.

Wondering if this tire just isn't a good fit for this car? Is 33/32 f/r psi too low for even wear? I'd be very happy to keep them at 45/43, as MPG increases dramatically (3-5mpg), and comfort isn't seriously impacted, but the noise is deafening at times..

 

alanclarkeau: Good advice. I'll be taking the car to an independent Toyota/Lexus shop for an alignment tomorrow. I won't put new tires on w/o making certain about the alignment.

I also figured hard cornering could be the cause. ALL FOUR tires are feathered, tires were rotated every 5-6k miles.

I was a new driver during the advent of radial tires, in the early 70s. Early radial tires could possibly have belts separate if the direction was changed. This is no longer the case. In fact on some cars, tire rotation in an "X" pattern is recommended for even tread wear.

 

Non-directional tires. I've changed PSI, all the way up to 45psi (51psi is the limit on the sidewall), MPG increased, but noise got worse. I honestly thought a few hundred miles with higher PSI might shave off some ot the offending surface.
Thanks for your experience about reversing the direction and the noise getting worse.
Hopefully I'll find the alignment is out, so at least I have an answer.

 

Dealer says alignment was out, but probably not enough to feather the tires. I'll get the numbers next Tuesday.
They DID find a bent rim, RR, on the inside. When they installed the new tire, it wouldn't seal properly, so it will be replaced under the CPO warranty.
New tires are smooth, no "drumming" sound. I've got the bent rim temporarily until next Tues...it isn't leaking enough air to be a problem, no major trips planned.

 

...which is why tires need to be rotated...

 

I'm 65, owned lots of different cars, tires. I've rotated criss-cross, front/back, or simply ignored the rotation. Every time I ignored tire rotation, especially on FWD cars, I've had to replace tires because of uneven, NOISY tire wear.
We do a lot of sustained highway miles, and the slightest bit of road noise gets really annoying, and with uneven wear, sustained high speed driving really chews up the tread.
Rotating tires keeps all the tires happy, wear evenly, and they last longer. FWD cars chew up front tires more than RWD cars.
I prefer to replace all 4 at once, maybe because I'm OCD????