17s killed my mileage
#1
17s killed my mileage
My first tank on new Xb auto was right at 30. I put on 205/40-17 Potenzas on 17X7 Motegi Rojas and mileage dropped to consistent 24 to 26. I run the pressures at 35. This winter dropped to 22mpg and tires looked low so I upped the pressure to 45! that sent the mileage back up to mid 20s but still no 30s. Its warm here in Omaha now and last tank with 35 psi in tires was 25.6. My Xb is stock save for the rims and tires. I drive 80% city stop and go and I am easy on the throttle. I hate the look of the stock rims and pie tin wheel covers but 4 mpg is a big sacrifice. Any one else have a similar exp? Thanks.
#4
Bigger wheels and tires create a heavier mass compared to stock.
So the engine does have to work harder to get the car moving which
would affect MPG, especially in stop and go traffic. Winter gas is
known for crappy mileage. I lost over 5 MPG during winter. Now
it's back up to normal.
So the engine does have to work harder to get the car moving which
would affect MPG, especially in stop and go traffic. Winter gas is
known for crappy mileage. I lost over 5 MPG during winter. Now
it's back up to normal.
#5
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Re: 17s killed my mileage
Originally Posted by fpcopo
My first tank on new Xb auto was right at 30. I put on 205/40-17 Potenzas on 17X7 Motegi Rojas and mileage dropped to consistent 24 to 26. I run the pressures at 35. This winter dropped to 22mpg and tires looked low so I upped the pressure to 45! that sent the mileage back up to mid 20s but still no 30s. Its warm here in Omaha now and last tank with 35 psi in tires was 25.6. My Xb is stock save for the rims and tires. I drive 80% city stop and go and I am easy on the throttle. I hate the look of the stock rims and pie tin wheel covers but 4 mpg is a big sacrifice. Any one else have a similar exp? Thanks.
#6
I have noticed just a slight change in mileage with my 18s, but when I bought them I made sure they were close in weight...the factory wheel/tire is approx. 40lb (I used my bathroom scale.)...my 18s are 42lb. The biggest thing I did notice was the way the wider tires track the road...kind of annoying at times, the the trade off on appearance is worth any small change in mileage to me.
#7
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Weight is only part of the equation.
Rotational inertia = mass x radius^2
So even if you have the exact same weight wheels, larger diameter wheels (they move the majority of the weight outwards, as almost all of the weigt is in the outer rim) will ALWAYS have worse mileage, power, and braking.
The only improvements you will see, performance wise, is the ability of adding larger brakes. Traction and handling issues can be resolved with higher quality tires (with stiffer sidewalls of the ame heigt) and wider wheels to accommodate the tires. That is, unless the new wheels are light enough to offset the change in radius (which means they have to be AT LEAST lighter than stock). Aesthetics are a different issue, however.
Rotational inertia = mass x radius^2
So even if you have the exact same weight wheels, larger diameter wheels (they move the majority of the weight outwards, as almost all of the weigt is in the outer rim) will ALWAYS have worse mileage, power, and braking.
The only improvements you will see, performance wise, is the ability of adding larger brakes. Traction and handling issues can be resolved with higher quality tires (with stiffer sidewalls of the ame heigt) and wider wheels to accommodate the tires. That is, unless the new wheels are light enough to offset the change in radius (which means they have to be AT LEAST lighter than stock). Aesthetics are a different issue, however.
#8
^^^ hes right, rolling resistance can be a bite in the ****. You may also want to try cleaning your MAF seonsor. I didnt notice a big loss with my summer wheels which were 215/45R17s. What little i did loose, i make up for in looks with a nice set of 17s.
#9
Re: 17s killed my mileage
Originally Posted by fpcopo
I drive 80% city stop and go and I am easy on the throttle.
You could try changing your driving habits. Maybe you'll get better mileage with heavier acceleration to get up to speed? Or a power mod or two- intake, header, etc.
#12
ive calculated my mileage with and without the 17's on my car. The 17's threw off my odometer by 1/10th. Basically for every 1.0 mile, my car calculates .9 miles on the odometer. My major drop in gas mileage can pretty much even out if i add in all those little .1 miles that are lost. Before wheels/tires i was gettint 300-320 a tank After wheels and tires im getting 260-280 a tank.
take .1x280=28
280+28=308
Putting me back on track for my old average with stock tires.
take .1x280=28
280+28=308
Putting me back on track for my old average with stock tires.
#13
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Originally Posted by MadMike550
I really like the ride quality on the stock 15's
#15
i had 15" allows for a while , no change in milage, im a VERY conservative driver though, i switched last year to 17" x 7" and i would swear they almost felt lighter then my 15's , either way i avagerage between 32-38mpg depending on whether i drive around town or back and forth to la.
#16
Originally Posted by bB2NER
Originally Posted by MadMike550
I really like the ride quality on the stock 15's
ahh..but the ride quality with the stock 15's...hmmm I guess vanity has a price
#17
yeah since changing up to 17" with the 35 profile its been a big change , have to be carefull of pot holes , the ride does get a lot rougher but i got more control and much better stopping response too. new wheel lugs are cheap and i hear their really easy to install ( oh yeah 18's are a hella pricey when they get busted my bf has VW 18s and had to replace a busted wheel and tired cost him $ 750.00 )
#19
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If you swap out the stock tires with 195/60/15 tires, there are plent of high performance uptipbs available that will get rid of the squishy balloon feeling. The stock ride quality has more to do with crappy tires than the larger sidewall. Those tires were NOT designed for performance. Besides the import scene, no professional racing cars use rubber band tires. Just look at F1. Their huge sidewalls make our stock 65 series look like low profile tires!
It's best to compare apples to apples, and comparing OEM wheels and tires to wider aftermarket wheels with sport tires is not a fair comparison.
It's best to compare apples to apples, and comparing OEM wheels and tires to wider aftermarket wheels with sport tires is not a fair comparison.