New tires = worse MPG?

[JamusMcFamus]

Vehicle: 2017 Miata, 6spd, 87,000miles.

Scenario: My daily commute is 35 miles, one way, 90% freeway. Mostly 60-65 mph. I recently (~6 mo) replaced the tires on it, with the same Michelin PS4 All Seasons that it had before. The previous ones had about 38,000 miles on them. The onboard MPG computer, with the old tires, showed an average of 37-38mpg. Since I installed the new tires (nothing else has changed), it's dropped to 33.5mpg. I never bothered to do the actual math, purely went off of the computer. Regardless of its accuracy, that seems like a significant drop. What would cause this, higher rolling resistance?

 

[Joe1]

Perhaps more tread on new tires makes a larger diameter and corresponds to less miles on the odometer.

Is the PSI tire inflation the same?

 

[fantastic]

Better tread=more rolling resistance...? I blame the "Spiky Nubs" sticking up.

 

[JamusMcFamus]

Perhaps more tread on new tires makes a larger diameter and corresponds to less miles on the odometer.

Is the PSI tire inflation the same?

I also considered this. And yes, same PSI.

 

[Patman]

Even though you replaced them with the same tires, the newer ones would be softer since old rubber hardens up. So that’s another factor to consider

 

[racer12306]

Even though you replaced them with the same tires, the newer ones would be softer since old rubber hardens up. So that’s another factor to consider

Or are they heavier, such as a design revision.

 

[dubber09]

That's my general observation as well - changing to new tires equals worse mpg. I think it's to do with greater rolling resistance due to 'softer' tire with more tread. If distance travelled is calculated based on tire revolutions then that will play its role as well.

 

[kschachn]

A few previous threads which may be of help:

Thread 'Lower MPG with new tires'

May 29, 2018

I installed General Altimax RT43 tires on my Accord back in January. I've put on 3000 miles since then and while they ride nice, I've lost about 2 MPG in fuel economy since the day of installation.

I consistently drive the same roads, maintain proper PSI, hand-calculate MPG and fill up at the same Mobil and Shell stations as always. Maybe winter fuel had a small part but we're on summer blend now.

Shouldn't the tires be broken in by now? Anybody else notice an MPG loss with new tires?

• mclasser
• Replies: 16
• Forum: Tires & Wheels

T

Thread 'What gas mileage difference + or - have you seen after installing new tires?'

Aug 15, 2020

I was wondering what if any fuel mileage difference you have seen after installing new tires? What to look for when buying new tires for better fuel mileage? TIA

• tenderloin
• Replies: 10
• Forum: Tires & Wheels

T

Thread 'tires and gas mileage'

Apr 3, 2004

has anybody seen gas mileage drop with the installation of new tires? last fall i replaced the oem's with a set of continental contiextreme contacts, and i'd say my average is down between 1~2 mpg. even compared to similar times last winter (old tires) it's down a bit. these are high performance all season tires. the grip is fabulous.

tia

• tweeker43
• Replies: 22
• Forum: Tires & Wheels

W

Thread 'Overall Diameter versus revolutions per mile'

Dec 3, 2010

I've been TireRack tire shopping. Recently, the tire I was leaning toward(Firestone Destination AT) has fallen to number 2, behind the Kumho Road Venture SAT KL61.

This alone is certainly not enough to change my mind, but what I find a little baffling is that the Specs for the FS tire say the overall diameter is larger than the Kumho, but the Kumho states less revolutions per mile.

It is this way in both the tire sizes I am considering.
The Firestone 28.9 diameter LT235/75/15 turns 723 RPmile
The Kumho 28.6 diameter LT235/75/15 turns 706 RPmile
------
The Firestone 29.5" diameter...

• wrcsixeight
• Replies: 13
• Forum: Tires & Wheels

M

Thread 'mpg down with Coopers'

Aug 1, 2023

Recently switched my 16 Odyssey from Hankook Kinergy GT to Cooper Endeavour Plus. The Hankook were 70k tires but after 30 they were at 3/32 so local DT warrantied them and I switched to the Cooper. I know new tires will generally get a little worse mpg but what would you consider excessive. I feel like its a noticeable 2-3 mpg difference on similar trips based on the trip computer.

Maybe just an anomoly but I like the mpg of the Hankook but not if they wear out in half the time. It seems like these vans tend to be hard on tires but longest wearing tires I ever had were older Hankook 727's...

• mbaker
• Replies: 8
• Forum: Tires & Wheels

L

Thread 'Is traction and rolling resistance a trade off?'

Sep 24, 2015

I was reading about loss of fuel mileage with Michelin tires compared to the set they replaced. I faced this on my 2003 Silverado when I replaced the OEM Goodyear Wranglers. I lost at least one MPG, maybe up to 2. I have much more traction with the Michelins, and the increased safety outweighs the fuel mileage hit.

Although tread design and compound influences traction more than rolling resistance, the tire carcass is likely the main design feature affecting the tradeoff. It may be that a tire that has good traction has a bigger footprint that requires the tire to flex more eating up...

• ledslinger
• Replies: 9
• Forum: Tires & Wheels

 

[Propflux01]

I believe 90% of the lost MPG result from the cause in post #2. Replace with the same brand and model of tire, and I bet you get the same results as the first set. Bad at first, slowly getting better as the tire wears. This has been my experience with tires an MPG.

 

[ripcord]

I was going to mention it's winter time and gas mileage suffers in the cold, but then I checked and saw that you live in South Carolina where it never gets cold.

 

[JoelB]

I doubt the onboard calculator is sensitive enough to account for rolling resistance. I'd look elsewhere for issues.

 

[benjamming]

A few previous threads which may be of help:

Thread 'Lower MPG with new tires'

May 29, 2018

I installed General Altimax RT43 tires on my Accord back in January. I've put on 3000 miles since then and while they ride nice, I've lost about 2 MPG in fuel economy since the day of installation.

I consistently drive the same roads, maintain proper PSI, hand-calculate MPG and fill up at the same Mobil and Shell stations as always. Maybe winter fuel had a small part but we're on summer blend now.

Shouldn't the tires be broken in by now? Anybody else notice an MPG loss with new tires?

• mclasser
• Replies: 16
• Forum: Tires & Wheels

T

Thread 'What gas mileage difference + or - have you seen after installing new tires?'

Aug 15, 2020

I was wondering what if any fuel mileage difference you have seen after installing new tires? What to look for when buying new tires for better fuel mileage? TIA

• tenderloin
• Replies: 10
• Forum: Tires & Wheels

T

Thread 'tires and gas mileage'

Apr 3, 2004

has anybody seen gas mileage drop with the installation of new tires? last fall i replaced the oem's with a set of continental contiextreme contacts, and i'd say my average is down between 1~2 mpg. even compared to similar times last winter (old tires) it's down a bit. these are high performance all season tires. the grip is fabulous.

tia

• tweeker43
• Replies: 22
• Forum: Tires & Wheels

W

Thread 'Overall Diameter versus revolutions per mile'

Dec 3, 2010

I've been TireRack tire shopping. Recently, the tire I was leaning toward(Firestone Destination AT) has fallen to number 2, behind the Kumho Road Venture SAT KL61.

This alone is certainly not enough to change my mind, but what I find a little baffling is that the Specs for the FS tire say the overall diameter is larger than the Kumho, but the Kumho states less revolutions per mile.

It is this way in both the tire sizes I am considering.
The Firestone 28.9 diameter LT235/75/15 turns 723 RPmile
The Kumho 28.6 diameter LT235/75/15 turns 706 RPmile
------
The Firestone 29.5" diameter...

• wrcsixeight
• Replies: 13
• Forum: Tires & Wheels

M

Thread 'mpg down with Coopers'

Aug 1, 2023

Recently switched my 16 Odyssey from Hankook Kinergy GT to Cooper Endeavour Plus. The Hankook were 70k tires but after 30 they were at 3/32 so local DT warrantied them and I switched to the Cooper. I know new tires will generally get a little worse mpg but what would you consider excessive. I feel like its a noticeable 2-3 mpg difference on similar trips based on the trip computer.

Maybe just an anomoly but I like the mpg of the Hankook but not if they wear out in half the time. It seems like these vans tend to be hard on tires but longest wearing tires I ever had were older Hankook 727's...

• mbaker
• Replies: 8
• Forum: Tires & Wheels

L

Thread 'Is traction and rolling resistance a trade off?'

Sep 24, 2015

I was reading about loss of fuel mileage with Michelin tires compared to the set they replaced. I faced this on my 2003 Silverado when I replaced the OEM Goodyear Wranglers. I lost at least one MPG, maybe up to 2. I have much more traction with the Michelins, and the increased safety outweighs the fuel mileage hit.

Although tread design and compound influences traction more than rolling resistance, the tire carcass is likely the main design feature affecting the tradeoff. It may be that a tire that has good traction has a bigger footprint that requires the tire to flex more eating up...

• ledslinger
• Replies: 9
• Forum: Tires & Wheels

Per CapriRacer in that 4th link, "All other things being equal, new tires will consume more fuel than worn out tires. This is due to the additional mass in the tread area for new tires." I don't want to be taking the quote out of context, so be sure to read that thread too.

 

[TheOilWizard]

I understand tires can cause slight deviations in fuel economy, but I'm skeptical it's the reason for 3-4mpg difference as you're reporting. I'm open to being educated on the subject if I'm mistaken here.

 

[kschachn]

I understand tires can cause slight deviations in fuel economy, but I'm skeptical it's the reason for 3-4mpg difference as you're reporting. I'm open to being educated on the subject if I'm mistaken here.

Yup. There are essentially zero controls on the myriad of variables in everyday driving. All of which (or a combination of several) can be significant.

 

[ripcord]

With 87,000 miles it might be time for some sparkplugs

 

[zzyzzx]

It's also a lot colder now than it was 6 months ago...

 

[walterjay]

MIL replaced her tires with an economy tire and took a consistent 3 mpg hit with her Camry. They were Tiger Paws.

 

[CharBaby]

All of the above!

 

[NormanBuntz]

Smaller sample size for the computer to measure? Let it run awhile.

 

[Patman]

I understand tires can cause slight deviations in fuel economy, but I'm skeptical it's the reason for 3-4mpg difference as you're reporting. I'm open to being educated on the subject if I'm mistaken here.

I’m a bit skeptical about that too. I just got new tires for my Civic the end of November and my fuel economy is still the same as it was last year in the cold weather (in the cold weather it averages 44-45 and in the warm weather 49-50)