I know 195/65 R15 is the Prius standard size for the 15" rims on my 2017

How much money are you saving by doing the switch? It may cost more to install and ship than anything else

 

You've theoretically reduced the tire radius by 6.5 mm (~1/4"). You'll need to rev higher to maintain any particular speed. Your odometer will be off. And less ground clearance.



I'd stick with stock size, just opens a can of worms.

 

It's weird: in OP's lists of threads he's started, there's three near-identical threads showing, to this one, and none of them have responses. And this thread, with responses, is not showing.

 

"this site is migrating to a server this week", safe to assuming this stuff is going to happen for the next half a year

 

I just received mine for a 2005 Prius, so good chance you'll get yours soon.

Posted via the PriusChat mobile app.

 

Your speedometer and odometer will regiter a couple % faster/higher and check the tire load rating to make certain that they will not be stressed.

JeffD

 

You're not alone, it's been hard to avoid double posting for close to 2 months now. I "reported" my post above, and tideland will likely sort it out.

BTW, going fine this morning, maybe out of the woods...

 

Test post.

 

going down a size means your going to lose another mile per hour. ie my speedometer is fast by 2 mph, when compared to my GPS on a flat straight drive across the valley floor. Measured over a 20 mile stretch of highway. My speedometer reads 70 mph, but GPS states that I'm only traveling at 68 mph. If I was to put 185/65r15 on the car, my actual speed will be 67 mph.

I've gone online and found if I move to a 205/65r15, I should be able to narrow the gap to 69.2 mph actual.

Tire Size Comparison

 

Forgetting about the very minor mpg savings and speedometer let's talk safety. The 4th gen Prius weighs about 3050lb and it's riding on tiny little tires that can barely support itself. You can barely turn the corner sharply without the tires squealing in protest. Imo it's simply not safe and the vehicle needs more tire to support it's weight. This is why people go up to a 205, because a wider tire makes the car more stable and has more grip.
Simply put the stock 15" tires, and probably in general a 15" tire, simply isn't sufficient for the weight of the car. The car has the same mpg ratings with the 17" wheels from what I found so what's the point in going to a less stable tire?

 

Two things about tire load. first when buying new tires check the load rating of the tire (its on the tire sidewall) and make sure that the new tires have the same or greater rating than the OE tires. If your tire squeal on turns, your air pressure is too low.

JeffD

 

Again the tires squeal even when properly inflated, or 2-3psi higher because that's where I run them, because it's not enough tire for the vehicle and they break traction very easily. Even easier after I upgraded the suspension, but even stock it was not hard at all when taking any corner slightly aggressive. They simply can't handle any type of sporty driving..
The first thing to do when buying any car, not just new tires is to ignore the psi recommendation in the door jamb from the car manufacturers and look at the max psi on the tire.

 

Our stock tires are 215/45R17, and through winter we use 195/65R15 snow tires. Stay close to Toyota recommended inflation. Not hearing noises on turns. Mpg better with 15” snows.