Almost 2,400,000 Prius have been sold in the United States since 2005. Many of these vehicles have 195 / 96 R15 tires that will require replacement at some point. I owned a 2010 Prius with Michelin 195 / 96 R15 Energy Saver tires, and when I sold the Prius, the tread wear was in line with the 65,000-mile limited warranty. They may be great tires, but they may not provide the best low rolling resistance for optimum mpg. My 2010 Prius only got 40 mpg – I’m unsure if it was the Michelin Energy Savers installed or the software upgrade for the inverter overheating problem the Gen 4 Prius’ encountered. Michelin has discontinued the Michelin 195 / 96 R15 Energy Saver tires, but most other Energy Savers sizes are still available. I could find any information on why Michelin discontinued the size of the Energy Saver. One complaint on Michelin’s website reported that the 195 / 96 R15 Energy Saver tires were chunking, which might have been why Michelin discontinued this size (is it possible that only one size would experience a fail?). Another possibility is that the tire did not have sufficient low rolling resistance to allow the Prius to achieve 54 mpg. I contacted Michelin support to find out if they would manufacture that size energy saver in the future. The support agent gave me no information about why Michelin discontinued this size or if Michelin would manufacture this size in the future. As a Michelin tire fan, I installed Michelin Defenders ($155) on the 2021 Prius Prime. After installing the Defenders, I took a 187-mile trip at an average speed of 68 miles per hour, and the Prius mileage was 40.9 mpg. On a prior 252-mile with the Dunlops, the Prius averaged 51.6 mpg. Another trip for 442 miles averaged 53.7 average mpg. (See attached energy consumption screen photos.) The 40.9 mpg is a drop of almost 20% in fuel efficiency with the Michelin Defenders. So, I returned to Discount Tire, and they agreed to switch the tires to another tire under their customer satisfaction (“We aren’t happy unless you’re happy”) program. For the 2021 Prius Prime with 195 / 65 R15 tires, the OEM factory tires are the Bridgestone Ecopia EV 422 plus (Firestone), Dunlop Enasave 01 A/s (a poorly rated / underperforming tire), and Toyo Nanoenergy A 41. I’ve never heard of Toyo, and the Dunlops only lasted 28,000 miles, so without Michelin Energy Savers, I chose the Bridgestone Ecopia OEM tires ($169), thinking that Toyota knew they would hit the mark for low rolling resistance and the 54 mpg. My 2021 Prius Prime came with the Dunlop Enasave tires. These tires enabled the Prius to achieve 54 mpg regularly. Unfortunately, these tires required replacement at 27,000 miles. Without much of a choice of energy-saving tires, I chose the Bridgestone Ecopia (Firestone) as a replacement. The tire has a 70,000-mile guarantee, but many owners report far lower miles from these tires. The Bridgestone Ecopia tires have a 90-day return policy if there are any immediate problems. The warranty is reasonable, with a percentage of wear correlated to the percentage warranty allowance (50% wear = 50% replacement discount). To have a comfort zone with these tires and protect my investment, I am relying on the Bridgestone warranty/guarantee if the tires have a shortened lifespan. The Bridgestone (Firestone) warranty/guarantee is a little tricky – one of the requirements is to keep the tires aligned. The only way to prove that you have kept the tires aligned is to perform regular, documented alignment checks, ranging from $90 to $100. One owner complained that Bridgestone denied the warranty adjustment because he had no alignment performed every 6 months. The Bridgestone/Firestone warranty manual has a Maintenance Record chart to record the mileage, date, and retailer for inspection, rotation, balance, and alignment. I am assuming that Bridgestone requires the documented maintenance records for the warranty. On the Maintenance Record, the Recommended Inflation Pressure includes a line for the months of the year, which may indicate that you are to have the inflation pressure measured monthly. Discount Tire assured me that if I rotated tires every 5,000 miles and kept the tires at recommended pressure, I would get good mileage out of the Bridgestone Ecopia. If you buy the Ecopia tires and intend to keep the Prius for a long time, the best bet is to buy a lifetime alignment for the vehicle, which costs about $200. Buying the lifetime alignment from a Firestone Dealer/Service Center keeps the information in-house since Firestone owns Bridgestone tires.