Mileage drop with new tires

Glad it all worked out in the end. Are you running the A29 version or the A41 for the Toyos?

 

A29: 89S 300AB (17lbs): https://www.tirerack.com/tires/Spec.jsp?tireMake=Toyo&tireModel=NanoEnergy+A29

A41: 91S 300BB (16lbs): https://www.tirerack.com/tires/Spec.jsp?tireMake=Toyo&tireModel=NanoEnergy+A41

The 2020 PP XLE I had came with the A41. Perhaps the increase in load index (despite the intriguing decrease in tire weight) was because of the addition of a fifth seat in the 2020 PP.

 

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The A41 has three ribs, that is what came on my 17. The A-29 has four ribs. I bought A-29's for my 10, and I can't seem to tell much difference as far as performance or noise. I guess that four ribs would give better traction and is less tire on the road for better mileage.

 

After further review... that's not correct. A-29's came on the 17, which do have four ribs. I ordered A-29's for my 10 since I liked them, but they sent me A-41's which have the three ribs. The order specifically says A-29 but I guess I was at the mercy of Walmart.

 

Yes the ultimate answer to everything is 42. Sometimes I let it go down to 40 but never below 40 for any vehicle I drive.
Tires on a Prius are very specific to say the least. And I suspect PP may even be worse.
Ecopias made in Japan are different than made other places so be careful.

I have had good results with some Yokohama, Ecopia, and Pirellis. Very tire model specific. Seems the rear wheels of a front wheel drive vehicle have different results with tires. But the front will kill your MPG every time with the wrong tire.

I actually put a pair of cheap Goodrich on my Honda Hybrid rear wheels and the MPG went up. Then I said ok lets do the front! Not the mamma. Dropped 10-12 MPG.

 

42 mph was the top EV speed for the Classic Prius.

42 miles is the available EV range for RAV4 Prime.

 

Get married at 42.

Tiger says that's the one.

 

There are so many tire threads I’m just grabbing this one to post on. Aside from a drop in MPG I am also suddenly experiencing an unusual situation that I did not see anyone else report while I was doing thread research on my tire replacement. Coincidence or related….?

I have a 2019 Prime and just yesterday logged 68,000 miles. I previously had the Toyo NanoEnergy A29’s on and changed them the other week at roughly 67,500 to Yokohama Avid Ascend GT’s. Toyo’s were the usual 195 65R 15 (A29) and Yokohama’s are 205 60R 15. According to tire calculators, the per-mile rotation went from 808 to 817 with the tire size change. Not a huge difference but a difference that adds up quickly with my personal higher monthly miles average.

The Yokohama’s ride nice to be sure and seem very quiet by comparison to Toyo NE, but of course, some of that sensation is just going to a new tire from very well worn old ones. My MPG in both Hybrid mode and all electric has taken a much bigger hit than I was expecting, even after roughly 500+ miles of break in on the new ones. I went from a hybrid run (65 miles each way on weekends – both Sat and Sun) of average 58+ mpg, down to an average 51/52+. All electric weekday to work, I went from having (average) full charge 33/34 down to 14+ (sometimes 15+) remaining by the time I got to work, which is 18 miles driveway to driveway, now down to under 10 miles remaining. This was immediate from the moment I had the new tires put on.

The WIERD part: I have now also immediately noticed, when I unplug my car in the morning, that my electric miles bank has gone from the very consistent average of 33+, sometimes 34+, down to 30+. And this morning I only had 28+ in the bank when I unplugged it. I live in California where the temperatures are very moderate and my car is always parked in my garage at night. Is this just a coincidence and something else has suddenly happened? Or can driving on these different size tires have caused an issue in the system would anyone know?

As far as the tires go, after a week and change I just cannot live with this tradeoff. And since I live in a mild climate with very little rain, and my drive patterns are consistently mostly in a straight line, I am going back to the Toyo’s. I phoned America’s Tire in Gilroy, CA and the General Manager Doug could not have been nicer to me over the phone. He patiently listened to my experiences, while even seemed genuinely interested actually, and said they would be most happy to reorder and get me into the tires I prefer. He did say this is their policy but since I have never done this before I am extremely pleasantly surprised. I do need to pay the labor but I am fine with that because I am very OCD and these new performance numbers are ruining my concentration…

Hope this helps someone else who also might have been on the fence about going away from LRR and standard tire size/weight. Give it deep thought….. And if anyone can offer any thoughts about my coincidental traction battery anomaly please offer your knowledge or perspective.

 

I’d stick with 195/65R15 too.

 

@High Mileage - Thank you for the comment and I see your point. That helps my mind as I have been worried something more catastrophic was triggered. Not that it should have but I am a George Costanza when it comes to worrying. I told the America's Tire guy that if I was going to be seen driving a Prius then you can bet I at least want the best MPG it can offer me. He laughed pretty hard at that one. But the truth is I love my Prius Prime and don't care what anyone on the road thinks. And I want her running back at factory specs.

Now the next thing I will be curious about is rechecking my speedometer. With the tire change I started testing with a GPS app on my phone to see what the mental adjustment was going to need to be. At 73mpg the GPS says I'm doing 67/68. But I have long wondered how accurate the speedo was but I had never thought to check it against a GPS. I will for sure do that once I get the Toyo's back on.

 

The new Toyo NE tires are back on as of today. Just driving the 32 miles from America's Tire to my work, I was already back to 58.4 mpg in Hybrid mode. I am hopeful to see my personal averages (my usual miles driven between Hybrid and all Electric) back up in the mid 90's per tank again...

 

I'm glad you said that because I want to show my own calculations, which seem to disagree, but I might be wrong.

First, I want to express my appreciation for this community. I've read numerous articles on this subject elsewhere and nothing comes close to the real world experiences you-all share.

Like the OP, I was shocked when my replacement Defender T+H caused my mileage to immediately drop from 53 to 45 on my 2021 AWD XLE. (The car came with Toyo A41.) And when I went googling, everything about decreased mileage seemed to say any rolling resistance effect should be 2-3%. So I suspect all that coverage is about ordinary cars, not something as sensitive and efficient as my Prius experience.

Anyway here are my calculations. It looks to me like there's not a downside to doing it. And if I can sell these fairly-new Defenders (9k miles on them so far) that further improves it. Am I missing something?

p.s. First, though, I'm going to try increasing the pressure to 39/35. I'll report back on that.

 

did the defenders come on the car?

 

Sorry for not being clear. The car's original tires (OEM) are the Toyo A41. I replaced them at 60k with Defenders.

I'll edit the post for clarity if I can.

 

Interim update: I overinflated the Defenders by 4#, bringing them from 36/35 to 40/39, and in the first 175 miles I'm getting around 52 instead of the 45 they've gotten till now.