Need to still replace all 4 tires at once?

Maybe download the owners manual in pdf format (Toyota Tech Info website is one source), and search it with relevant terms. I doubt it matters, but clueless.

You’d be doing this to economize somehow? I’d just rotate regularly, replace all at same time.

 

If your rotating the tires every 5K miles, per OEM manual, all four should wear out at about the same time - unless you have brake and/or suspension issues.
As far as replacing tires goes, replacing them in pairs per axle is fine if moneys is tight. Just beware that the semi-bald ones aren't going to grip as well as the new. The rear end may swing out, if you replace the front with new - even in an AWD. I don't think Toyota's AWD specs. are as tight as some other cars, but you may get traction control issues, if the wheel spins are too far out of wack.

Hope this helps....

 

They could also be asking in case one tire gets damaged. If a tire gets shredded at 60% lifespan, it's a lot easier to stomach replacing two* than replacing all four.


I suspect replacing in pairs is fine, but I don't have proof of that. Sorry.



*and then keeping the other good tire as a backup

 

One thing: when tire shops replacing just two, with a front wheel drive, they always want to put the new ones on the rear. How they're ever going to catch up (in wear) with the front is one conumdrum I've never heard answered.

I've thought about it, and my conclusion: "just never do that, replace all four".

Beside which, driving around well-worn tires in front, and near-new ones in the back, would play havoc with my OCD.

 

That's the theory, and I find it close to practice, but I also write down tread depths every time I rotate, and it doesn't take long to see the wear rates spreading out in practice.

I'm also driving little enough that the recommended six-year replacement interval is as likely to be the replacement reason as treadwear (at least for the long-treadwear tires I like to buy). And it's always a wildcard which tire gets taken out by a road hazard, and messes up any tidy scheme you have in mind.

And for all the hoopla about matching pairs or sets, I've twice had road-hazardized tires just singly replaced, and got no complaints from the car about wheel speed mismatches. I've been lucky enough for this to happen when the other three aren't very worn, so the difference from adding a new one is within tolerance. I also was not sternly warned away from this course at either tire place; they looked at the overall tread depths and said "probably be fine".

I'm thinking I may leave behind the whole replace-in-sets mindset and start just replacing my most-treadworn single tire every 18 months or so (at least if the same tire is still being sold). That'll satisfy the six-year age requirement with a less-lumpy cash flow, and help ensure that whenever a road hazard necessitates replacing any one tire, the treadwear difference won't be too extreme.

 

As Mendel said, check the manual. The Prius's AWD system is not the same as a Subaru that's a mechanical system that delivers the same power to the front and rear.

 

In my experience, the driver's side tires goes down slightly faster than the passenger side - especially if you subscribe to the front back rotation schedule. Probably due to my fat asset, in the driver's seat
I rotate my tires, clockwise around the car. That seems to give me more even wear across all 4 tires.
If you do get an irreparable tire, I'd recommend putting the new one on the rear axle and see what it does. It may intermittently and for no reason, set-off the traction control sensors (you would see this on U-turns or tight turns). You can use an empty parking lot to test - do both left & right tight turns to test. If it does give you an issue, the car can be more easily controlled in that position as opposed to the front axle. If it does give you issues, you'll need to replace both tires on that axle. Save the half worn one for a spare. The other option is to 'shave' the new tire down to the same thread depth of the other 3. The cost would be about the same as getting the additional new tire, so I would opt. to get two new for an axle.

Hope this helps......

 

The skid ECU also has an extra-sensitive sensor test mode, described in the repair manual for use after changing a sensor or hub. In that mode you drive slowly around a spacious parking lot following a particular routine, and if it buzzes the right way at the end of the routine, everything passed. It can catch problems that might not otherwise be caught under just normal driving.

If replacing one damaged tire, the chance of any trouble is highest if the other tires are substantially worn at the time. If they are closer to new, there's less likely to be any issue.

If I can get on and stick with a new practice of changing one most-worn tire every 18 months or so, I'm thinking there'll be little chance of an issue with a road hazard forcing a replacement off-schedule. We'll see how it goes.

 

You should be fine replacing pairs only since the eAWD system isn't interconnected like in a traditional AWD or even 4WD. But I wouldn't rotate tires though.