Hey Scotty! I have a 2016 Toyota Highlander 39,000 mi and recently installed a new full set of Michelin tires. My old tires were mis-matched - brand wise and 1 of them leaked so I was driving on "low air" quite often. 33-36 psi in these. BUT I was getting 23 MPG with the old tires and am now getting 19.5 with the new. These new tires are inflated to 42psi. Driving in ECO mode for both. Both sets recommended size/brands for the highlander.
What could cause these new properly inflated tires to lower my mileage. The change happened the day I installed the new tires. No massive temperature changes here in Fla either.
Thanks!
What is the recommended tyre pressure from the OEM? Was your previous set bald/down to the tyre wear indicators?
https://www.tirerack.com/tires/tiretech/techpage.jsp?techid=177
New tire pressure (42 psi recommended by Michelin). Old tires : 1 was bald, 1 was odd ball new tire prev owner had replaced both @34psi. The other 2 (rear) had slow leaks, 1 worse than the other, so can't ever say what their PSI was. Mostly waaay lower than recommended.
Michelin recommends 42psi? Is that what you read on the outer sidewall of the tyre?
A cursory google search reveals the recommended tyre pressure from Toyota for the stock tyre size of a 2016 Highlander is - 35psi https://tirepressure.com/toyota-highlander-tire-pressure#2016
Oh & regarding your worse gas mileage, yes, it’s normal to experience a little worse gas mileage compared to your previous, almost bald set of tyres. Have a read of both the links I provided.
Happy new year!
Interesting info on rolling resistance. Good to know.
1) different tread pattern and rubber composition can change performance properties of the tire, making the engine work a little harder
2) even though they might have the same size numbers as your old tires, there will be small differences in diameter and tread depth, which could make a percent or two difference in your mileage.
3) You mileage might APPEAR to change, but the calibration between the computer and the tire size is never perfect. Your speedo and odo readings have a margin of error. You can demonstrate this by using the GPS in your phone.
Why increased tire pressure in new tires?
I understand that you did not ask this question, but since it is very important, I write couple of sentences here:
The tire pressure you need for your car can be found on the driver side door jamb. Stick to that. The one that you find in the tires is the maximum pressure that you can have and it is dangerous since it results in loose of handing and possible blow up the tires.
Thanks everyone. The tire store where I purchased the Michelin defender LTXs put 42-43 psi in them. I thought it was high as well ( my TPMS was telling me the psi) so I looked on the sidewall to verify and it was what the tire recommended, so I'm good with that. I was just kind of expecting better mileage due to the old ones being balder/lower on air.
I'm just going to have to deal with it. I love driving on new tires especially after having to fill one with air every 3 or 4 days.
Thanks again!