I currently have the OEM Bridgestone Ecopia EP422 and I think they are very loud. America's tire suggested the Michelin Defenders and said they were were quieter. Does anyone have any experience with the Defenders? I know the MPG are not as good as the Ecopias but I'll choose less noise over a few MGP any day.
Really pleased with these: https://www.tirerack.com/tires/tires.jsp?message=singleSize&tireMake=Yokohama&tireModel=AVID+Ascend+GT&cameFrom=selectOE&partnum=965HR5ASCGT I got them in May last year. The original Toyo Nanos only had 24,803 miles and were down to 5/32" of tread. Would have been OK for a while, but we were heading for the Colorado Rockies and it was going to be about a 6,000 mile trip and I wanted to be ready in case we got any snow up there. (We did, but not heavy.) I have put almost 20k miles on the GTs since then. Tread is down to 9/32" from the initial 12/32". Wet performance is exceptional. Noise is not an issue, but I have no idea how they compare to the Defenders. They are no louder than the Nanos and might be a little quieter. Hard to tell.
The Michelin X-Tour is sold at warehouse clubs like Costco and Sams and is the same as the defender, just a little cheaper. I have the X-Tour tires and find them wear well and be quieter than the original tires but never had Ecopias to compare. Unfortunately, I find road noise to be high my the gen 3 Prius no matter what. Just not enough sound deadening material. Sounds like the same for the gen 4.
On my 2020 Prius Prime Limited, I immediately removed the Toyo's and put Michelin Defenders on.... gas mileage is fine, noise is much less, ride is great.... but initially noticed the front end very susceptible to cross winds, car jumping around the lane, needing constant correction, so had the dealer check and adjust alignment (slightly), and brought pressures down to 36/35 (instead of closer to 38), and car is much better behaved now.... really love the tires.... and the car - so far.... also have a 2017 Chevy Volt with Michelin Primacy.... another great tire, but not available in the Prius 15" tire size......