Noticeable decrease in MPG with new tires
- Thread starter jsm172
- Start date
gprabhu
Active member
What tire pressures are you following. I inflate tires to 36 psi cold, and get a good balance of comfort and economy.
When you change tires, shop will follow placard on door and reduce PSI to match placard (or get it wrong all together and set to 30 psi)...
They are around 38 psi, which is pretty high. I'm hoping its just a wear in period and it will get better.
hskrdu
Top Post Dawg
Many owners will report lower FE with new tires, if all/most other factors are similar. Of course, if you replace heavy, wide, sport tires with lighter, narrower, LRR tires, the new ones will probably show improved FE.
Newer tires, if all else is equal, are heavier- and that weight is at the corners. New tires are taller, which decreases the reported mileage (reducing calculated FE). Newer tires have more rolling resistance than older tires, often even compared to non LRR tires. "Old" tires, (especially ones that are well worn and about to be replaced) are often at their peak for higher observed FE. They are lighter, shorter, and have (generally) the lowest rolling resistance of their lifespan. This makes the swap to new tires more dramatic in observed FE.
A search will reveal lots more good info.
Newer tires, if all else is equal, are heavier- and that weight is at the corners. New tires are taller, which decreases the reported mileage (reducing calculated FE). Newer tires have more rolling resistance than older tires, often even compared to non LRR tires. "Old" tires, (especially ones that are well worn and about to be replaced) are often at their peak for higher observed FE. They are lighter, shorter, and have (generally) the lowest rolling resistance of their lifespan. This makes the swap to new tires more dramatic in observed FE.
A search will reveal lots more good info.
Last edited:
sunshine x
Member
Have the same tires and had same initial results.
I think (and told by my tire guy) that even tires need to "break in" a bit as mileage did come up again to close the same as OE tires.
Have +/- 33k miles on them and still ok but far from quiet in my opinion.
I think (and told by my tire guy) that even tires need to "break in" a bit as mileage did come up again to close the same as OE tires.
Have +/- 33k miles on them and still ok but far from quiet in my opinion.
bustNfuel
Veteran Member
It could be the difference in rolling resistance between tires that are worn out and hard (less tread rubber) and new tires with full, soft tread.
I just replaced my original Continental ContiPro Contacts, 235/45 R18, with identical tires, but have not driven through the first tank yet.
After a few tanks I'll have a good idea of any changes.
My local VW dealer had a set and they were competitively priced so I used my Goodwill $500 card towards them and a 4-wheel alignment. These are the smoothest riding tires I've had in a long time, and really quiet compared to my originals with over 55K miles.
I just replaced my original Continental ContiPro Contacts, 235/45 R18, with identical tires, but have not driven through the first tank yet.
After a few tanks I'll have a good idea of any changes.
My local VW dealer had a set and they were competitively priced so I used my Goodwill $500 card towards them and a 4-wheel alignment. These are the smoothest riding tires I've had in a long time, and really quiet compared to my originals with over 55K miles.
DaveTC
Well-known member
I had the same thing (indicated decrease in FE) with some Michelin tires when switching from the original Hanook tires. I attributed it to increased rolling resistance. In addition, the tires had a slightly greater diameter so that mileage would appear lower. I noticed this because the MPG would not be indicated until just before I got to a stop sign near my house in the morning and now it is not indicated for another 75 feet or so past the stop sign.
czeetah
Veteran Member
Get some Michelin Energy Saver tires.
You might slide around in corners from the hard rubber but oh well
You might slide around in corners from the hard rubber but oh well
hskrdu
Top Post Dawg
I replaced w/ same tires and no loss of MPG's. Just went on a 520 mile day trip from Syracuse, NY to Hershey, PA and ave 42 mpg's. Local MPG's still running mid 30's. Sadly, don't think we will see this kind of mileage again w/ the 1.8 gasser.
bustNfuel
Veteran Member
I have lost about 2 MPG per tank average since putting on the exact same tires.
Compare my previous Fuelly logs in the link in my signature. The new tires were put
on at 55,400 miles, on September 2nd.
Compare my previous Fuelly logs in the link in my signature. The new tires were put
on at 55,400 miles, on September 2nd.
Spike_africa
Veteran Member
Get some Michelin Energy Saver tires.
You might slide around in corners from the hard rubber but oh well
Yeah, traction isn't important when it comes to tires....