I am new to this forum, and I did try to search other threads before posting this one. My Prius 2010 (III) mileage dropped by at least 5 mpg after a tire change. I am not sure what is going wrong. I read many articale but no one gives a concrete clue. Here are some details specific to my situation: I was getting 45-47mpg with my driving conditions. I got my 35k miles service done, and dealer suggested a tire change. Tires were worn, so yes it was a time to change. I went to Costco and got Bridgestone Ecopia 422. Then for a week I saw a drop and attributed to wheel alignment not being done after the tire change. Then I went to Firestone center and got the wheel alignment done too. Still no change in mpg. It is always 40-42. It has run approx 400 miles now (both freeways and local). I took my car to the same known routes (friend's place 40 miles to-fro), and I know that doing so generally used to increase my mpg on display panel and it would bring it from 45 to 47/48. But now 45 is no where to be seen. I am stuck at 40-42 range. Here are few more variables: 1. N2 air at costco whereas earlier I never got N2 in my tires. But I heard it should increase the mpg if at all. 2. Costco guys set the air pressure at 32/34 as recommended. I drove for a week in that and then increased it to 40 psi thinking that it might have some impact, but no go. Currently I am at 40psi (checked again today), but still hitting 41.8mpg. 3. My dealer did not reset the tire-rotation reminder at 35k service. So this reminder still comes. Not sure if on-baord chip thinks that this is bad, and mpg calculation is getting adjusted due to that. 4. When I am on cruise control, the mpg indicator bar used to be at 50mpg, but now I see that it is one notch down (i.e. at 45mpg). And then it increases a notch sometimes and comes back (so may be 47.5). But earlier it used to just get at 50mpg and be there on the same route. I feel frustrated knowing that Bridgstone tires are suppose to increase my mpg, and I was so looking forward to it. Can someone in this forum please help. I have high hopes that I will get some solution. I read some tires/mpg thread and it seems 44psi on bridgestone gives max mpg. I can try that, but I used to get 47mpg with 35 psi (dealer set) itself. What might be going wrong. If you can point me to other threads where something like this might have been discussed, it would be of great help too. Thanks a lot for reading and responding. I am
I had yokohama tires fitted from factory but they worn out at 35k needing replacement. Yes, I searched this site today only. But did not see any case similar to mine. Rather I am more frustrated as I read people getting 60s-70s in mpgs. I will be happy to get back my 47-48 mpg figure!
It usually takes 1-2000 miles for tires to break in and give max mileage. Your old tires were very broken in, so its not a fair comparison. The nitrogen has little to no advantage over regular air (which is mainly nitrogen) and shouldn't hurt. You can reset the maintenance reminder yourself, but it doesn't make any difference in mileage. How's the weather been since you got the new tires? Colder temps can make a big impact on mileage.
Don't get discouraged by the hyper-milers who go to some rather extreme lengths to get those kinds of numbers. They might be something to strive for as you learn some of the techniques, but unless you have similar routes, traffic patterns, etc., those kinds of numbers are difficult to get and maintain. And some of them spend a lot time finding a route to give those numbers just so they can post them. I don't quite understand why people say worn-in tires get significantly better mileage. Unfortunately, we took a long trip shortly after buying our Prius, so I wasn't able to see if the mileage increased over the same routes as the tires wore. I suppose there is some benefit, but I find it hard to believe that would make you go from 47-48 to 40-42 without something else changing, like ambient temperatures, and that doesn't seem likely in San Mateo. If you read all the tire threads, you'll see that people have very different experiences with the same brand/model tires. I've read where people go from Yokohama to Bridgestone, Michelin, Goodyear, etc., or vice versa and have totally opposite results. I've also read about people who experimented with air pressure and saw no discernable benefit high or low. I also don't understand the wheel alignment thing, but I'm new to Prius and have never had to have the wheels aligned on any car I've owned just because I got new tires, or even new wheels for that matter.
Many people report a small increase in mileage after the first couple thousand miles. Not enough to be OP's whole issue, but add in lower temps (which makes a bigger difference on shorter trips and city driving) and winter gas and a 5MPG drop isn't out of the question.
What pressure did you run the old Yokohama's at? What model were they specifically, if you recall? There's a fair number of variables at play since the change, not the least being the time you had the new tires at 32/34, before raising them. And the spec is 33/35 (rear/front) I believe. The alignment was likely not needed, if you haven't hit a curb or similar. Hopefully hasn't messed things up. Does the car feel/steer the same since the alignment? Do you have a document, showing the alignment, any adjustments? How worned were the Yoko's? It's not a big difference, but going from down-to-the-wear-bar tires to brand new, in the same size, there's a slight increase in the outside diameter of the tire, which will make the car think you're travelling not as far. It can amount to 1.5% reduction in O.D.. Also, weather, traffic might be factors. All in all, I suspect you're going to end up slightly lower in mpg, because the EP422's are not equal to the Yoko's. But not by much. See how it goes after a tank or two with the higher pressures?
Maybe the search function here is broken. A LOT of users seem to be saying this lately. There should have been a lot of hits, depending on what you searched for.
Tire pressure IMO hurting MPG ,,,,, 42 front 40 rèar , you will notice better MPG ,,, also If you are in winter temp area , would advise grill blocking
