I had a 2017 Prius that i was averaging around 4.2 l/100 (56 us mpg) when on the factory tires -ecopias. I was rear ended and it was totaled , so I ended up replacing with a 2017 prime. When I got the car a few weeks ago it had almost new Uniroyal tiger paw a/s tires on it. I had to do a long trip right after getting it of 2500km and could not get lower that around 5 /100km (47 us mpg) All of this is running highway around 117 kph or 72 mph' and it felt down on power especially on inclines. I checked the 12 volt battery after one morning and it was 12.1 volts so swapped in a new one but it made no change in mpg. Air filter was clean. I took off the Uniroyal tires and put on a set of Bridgestone ecopia 422 plus tires and right away my mileage is up to 4.1/4.2 l/100km or 56 us mpg. These mileage numbers are calculated from fill ups and subtracting the km driven on electric per tank so are very close to accurate . My electric range also went from 37/40 to 45/47 km on average. You can feel the difference in how it drives as it feels like it handles inclines better and the rpms are lower on the same inclines. I do on average 340 km every day with a full charge in the morning and one before heading home so it is a huge difference in fuel used plus the 10km driven on electric. I would suggest to anyone to avoid the tigerpaws Dale
With our first Prius, at one point I elected to cheap out on tires and mileage went down noticeably. Over the life of the tires, I calculated that I lost money on the deal by paying more for the extra gas than better tires would have cost in the beginning. Lesson learned.
