I have been reading priuschat for a month. I just bought a 2018 Aqua with 155,000 km. It came with 185/60R15 tires. I had it lifted about 1.5 inch. I drove about 2000 km. Mostly on asphalt. But 400 km on dirt and stone (kind of like gravel, but natural assortment so 2 or 3 inch diameter or bigger are mixed in.) Mostly unmaintained. I bought some tires. Used but pretty good condition. Front: 255/65R15 32 psi. Rear: 195/65R15 30 psi. Got an alignment. Drives very nice. Very minor rubbing when turn right when parking. Normal driving no rubbing. Speedometer was over by 8%. Now over by 1.5%. Odometer was under by 1.5%. Now over by 8%. I am using a GPS speedometer app to compare the speed and fistance. GPS 191 km. Trip meter 206.5 corrected by 8% = 191 km. Asphalt 2 lane highway. Rolling hills. Half the trip East and the other half West on the same highway. Fuel used (92 octane) 6.44 liters. 30 km/l = 70 mpg. Trip meter showed 26.3 kml avg. Drove in D all the way. Didn't need to use the brake to slow on any downhill dips. I tried to stay close to 80 kmh. (+/-5). The reduced engine speed was much quieter.
2018 Aqua Front: 205/65R15 Rear: 195/65R15 The Aqua has 15 x 5.5 rims, so a 205 width tire will fit. The Prius C has 15 x 5 rims, thus can't use a 205 width. A 195/70R15 is about the same diameter as the 205/65. The 16 inch rims on the Prius C is 16 x 6, so 205 width fits. If you want wider tires, don't forget about tire chains. The 205/65 tires rub just slightly when turned completely right or left Just drove about 100 km on some dirt/rocky roads. No rubbing handles nice, feels better.
Stand corrected; Both Toyo and Yokohama say 205 width on 5" width rims "The 205/70R15 Yokohama AVID TOURING-S has a diameter of 26.4", a width of 8.2", mounts on a 15" rim and has 787 revolutions per mile. It weighs 22.4 lbs, has a max load of 1499 lbs, a maximum air pressure of 51 psi, a tread depth of 10/32" and should be used on a rim width of 5-7".
