New Wheels MPG Dropped a lot!

[lilcrzytimmy]

Last week i got new wheels installed and saw a massive dropped in my MPG. My driving habits have not changed and all my maintenance are up to date. I know having bigger wheels will drop my mpg but not by 10mpg. Did anyone else have similar specs and saw this drop? Whats your results?

Before:
Wheel: 17" OEM Salamanca
Wheight ~23lb
Tire Size: 225 45 R17
Tire Brand: The OEM Continental. dunno which one
MPG: ~40mpg

After
Wheel: Neuspeed RSe14
Weight: ~21lb
Tire Size: 225 35 R19
Tire Brand: Michelin Pilot Sport AS3
MPG: 30MPG

I havent calibrated my speedometer yet but the difference isnt much, at least comparing to an app i used. probably about 1 to 2 percent decrease in mph.

 

[exedotbat]

I would have thought it would get better with less rotational mass.

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[frank5o]

Are you calculating your mpg, or going by the mfi?

 

[SFGiants]

I would attribute the loss in MPG less to the larger wheel and more to the far grippier tire you now have. Still, that decrease seems extremely drastic.

 

[tbombsgen6]

I would have thought it would get better with less rotational mass.

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overall weight of wheel/tire combo is probably the same, but its harder to rotate if radius is longer, which i would assume the new wheels/tire are....at least slightly. but i also agree that the culprit is most likely the tire change as I experienced similar issue switching tires. I had to experiment with pressure to find the right balance. New tires are at 42psi vs old oem at 38. think I could go even higher. But try increasing tire pressure slightly

 

[lilcrzytimmy]

Each tires is about 43 to 45 PSI. Max pressure is 50 psi. Will decreasing my tire pressure to ~40 psi do much? ill play around with it. i havent calculated the actual mpg yet but looking at where my fuel gauge is at, im suppose to have been able to drive about 400 miles with a quarter tank left but i have only driven 300 miles.

Perhap it could be the newer stickier tires. Ill see how i do in the second tank after a little wear and tear. I just wanted to see what others were getting if their newer wheels were lighter but bigger. This is my first time swapping out for newer wheels. cross my fingers.

Does anyone with the similar wheel specs and same tires have any results they can share?

 

[engineered2win]

Theres a significant difference in rolling resistance. The OE Conti's are LRR, while your brand new Pilot Sports are significantly more sticky(for a no season tire) and have higher rolling resistance. A new tire will have more rolling resistance than the same tire that's worn, because of tread block squirm. Albeit the pilot sports should have minimal block movement, it will still occur to some degree, which affects FE.

 

[Bino]

Each tires is about 43 to 45 PSI. Max pressure is 50 psi. Will decreasing my tire pressure to ~40 psi do much? ill play around with it. i havent calculated the actual mpg yet but looking at where my fuel gauge is at, im suppose to have been able to drive about 400 miles with a quarter tank left but i have only driven 300 miles.

Perhap it could be the newer stickier tires. Ill see how i do in the second tank after a little wear and tear. I just wanted to see what others were getting if their newer wheels were lighter but bigger. This is my first time swapping out for newer wheels. cross my fingers.

Does anyone with the similar wheel specs and same tires have any results they can share?

After the tires are scrubed in they should get even stickier. Most tires if not all come with a coating on them. When that wears off you get the full grip of the tires. So in fact it should get worst. 10mpg is way to much of a drop.

Are you sure your not pushing the car alittle harder now that you have some grip?

With my stock 225 17 Denvers I was getting around 30 Now with my 235 18 Detroits PSS I get around 26.

 

[SFGiants]

Each tires is about 43 to 45 PSI. Max pressure is 50 psi. Will decreasing my tire pressure to ~40 psi do much? ill play around with it. i havent calculated the actual mpg yet but looking at where my fuel gauge is at, im suppose to have been able to drive about 400 miles with a quarter tank left but i have only driven 300 miles.

Perhap it could be the newer stickier tires. Ill see how i do in the second tank after a little wear and tear. I just wanted to see what others were getting if their newer wheels were lighter but bigger. This is my first time swapping out for newer wheels. cross my fingers.

Does anyone with the similar wheel specs and same tires have any results they can share?

Decreasing your tire pressure will increase your grip, thereby decreasing your mileage. A lower PSI also makes your tires wear more quickly. If you're currently at 45 PSI, I suppose you could go higher. That's fairly high though.

I have 18" wheels, 225/40/18 Bridgestone summer tires, and I personally didn't notice very much of a mileage decrease (if any, to be honest). My wheels are significantly lighter than the OEM ones, however (about 7 lbs lighter per wheel). I also lowered my car about 1.5" which helps with mileage as well.

 

[maxtdi]

45psi? Um no... that's way too high. The stock PSI is 38.

That said, over how many miles was the "new" mpg calculated?

 

[lilcrzytimmy]

yeah, 45 is high, thats why i don't wanna add anymore pressure. especially in this hot hot weather of Southern California. The Mpg is calculated over ~300 miles.

Well i have yet to lower the car to close the wheel gaps and decrease some drag. i kind of want to rebalance the tires to see if it was done correctly. This morning i noticed a small vibration in the front driver wheel. if anything, it is what it is. ill learn to change driving habits to maximize my mpg. small price to pay for good looks. and i have to admit, these tires are fun. i have been holding back on pedal cause i wanted to see how much my mileage would change.

 

[maxtdi]

You shouldn't see that much of a drop still

 

[smrtypants44]

45psi? Um no... that's way too high. The stock PSI is 38.

That said, over how many miles was the "new" mpg calculated?

He should keep the pressure at 40psi+ to make up for the fact that 225/35 XL tires have a lower load rating than oem tires.

 

[Chris@Revo USA]

45psi? Um no... that's way too high. The stock PSI is 38.

The stock PSI is done as a compromise of many things, mostly noise and comfort. Also a stock 17 and an aftermarket 19 have very different pressure requirements.

Not that I am saying that 45psi is right, but just about every production tire in these sizes can safely be run at 45psi, what the tire manufacture says matters in this type of situation not the car manufacture.



That being said I have run my DWS at 35psi-45psi and it makes no difference in fuel economy but the ride goes to utter crap over 40, this is on 18s with KW V3s

 

[U-20T]

Like we said above the gripier the tire the less mpg, most likely the reason. My 255s on enkeis are at leasy 5-7lbs less a corner but the 255 on a trackable tire took about 5-7mpg out.

Highway before was 34ish mpg and now 29-30mpg on a loooong drive.
Around town before was 27-30mpg and now 24-25mpg is good.