Changing tire size from 15 to 16 or 17

15 inch wheels can have the tallest tires. 17 inch wheels obviously trade 2 inches of rubber for 2 inches of aluminum. This will aid handling at an expense in ride quality. Since aluminum wheels are heavier than rubber tires, there is also a loss of MPG.

 

The 16 and 17 rims must be installed with smaller diameter (read thinner) tires so you don't change the overall gearing of the drive train.

You could try 185x70 15 inch tires but they would only raise the car about .2 of an inch.

I would stick with the stock size. Perhaps Goodyear Comfort Tread tires would give you a softer ride.

 

well, since the gy integritys really suck, you could go with 205/60r15 LRR tires if you don't want to buy new wheels (lightweight wheels are expensive). the wider and slightly taller 205's will give you: more accurate speedo reading, much better traction, and if you buy good tires like Michelin, a quieter ride, with little or no loss of mpg. I had 205's on my '04 and they were better in every way than the 185's.
if you must go with bigger wheels, 16" enkei rpf1 are like 13.7#-- pretty light. with LRR tires you might not take a hit on mpg. if you go with 17" or bigger wheels, you will definitely lose mpg, and will have better handling but with a rougher ride.
sites like tire rack give tire height in the specs, so you can see how tall the oe tire is vs. whatever tire you want to buy. I wouldn't want my replacement tire to be more than 1" taller than the junk integritys, or your speedo will be way off. definitely go with wider tires whatever you do cause unless you drive like a granny, the 185's just got no traction. aside from being noisy at highway speeds, I find they easily squeal on corners and in the rain they are just plain dangerous.

 

Yes 3 to 8 MPG. You will save more money than the tires cost

 

If you want to go to 16 inch wheels on a budget I suggest you buy a set of Prius touring wheels. This size is standard on all UK and European gen2 Prius. There must be many sets of these available from wrecks or people that have changed to aftermarket wheels. Fitting these with 205/55/16 tyres LRR tyres will not hurt your economy, and will greatly improve the handling and stability of your car.

John (Britprius)

 

I never see touring wheels for sale; Toyota stupidly didn't sell (or perhaps the dealership morons didn't order any) touring models in some areas. in fact I've seen no more than 3 touring models in the DC area. I suspect they were purchased elsewhere or special ordered.

 

It's true! When I bought my car in May, it had new nexen, non LRR tires. Made me sad it's hard to justify new tires when your car has new tires. Lol