How much of a mpg loss would I get from changing stockies on the 09 is250 awd to some 19's?

 

somewhere in the neighbourhood of 0 mpg. the difference would be negligible.

 

There would be some impact. It would depend on the wheel/tire combination, will determine the impact.

People who had 18"s going to 19"s notice an impact, therefore going from 17" to 19"s would be larger.

 

We're not talking huge differences here. the only differences would likely occur from acceleration and the inertia of the wheel itself. I was under the impression that it's the tires that have more of an impact than the the rims.

 

It depends on many factors. Most of the time, when you up-size rims, you add more weight. I say most because of manufacturers like Volk have super lightweight models available. It also depends on the tire you choose, sticky sports or race tires will create more friction (grip) thus make the engine work harder than ones that dont. Also there is a big differnece in weight between tire manufacturers.

 

Yes, not huge. I was just doing the math/theory wise. MPG, maybe a 1-2 mpg hit according to some users but it depends on other factors which we seem to be all to be aware of.

To a car, you won't feel a difference unless one is in tune with the car. Now if you do this to a bicycle and use your feet, you will feel it!

 

So I guess the answer is.... it depends.

If you get heavy wheels with wider tires, you could expect some drop in mileage, albeit a small one. Lighter wheels with an all season tire (less grippy than a summer one) would probably yield you the same mpg's you're getting now?

 

You might want to do some reading on the term "Unsprung weight" google can be your friend.

 

not enough to worry about.

 

I laugh a bit at some of these responses. True it's probably not much, maybe 1 or 2 if you're going with the same quality wheels/tires when you upgrade. But for most of the guys that peruse these forums when asking the question "should I get bigger wheels" the answer is always a resounding YES. So when one asks "will there be a noticeable mileage difference if I go up to 19's?" The answer will be-OF COURSE NOT! Because a "noticeable mileage difference" might in fact be a negative to having bigger wheels! The answer-bling trumps all :P I personally don't go any bigger than 18's merely because of the reduction in ride comfort and the ridiculous expense of 19's and larger.

 

^
To add on top, the advantages of having bigger wheels such as less tire deflection, sticks on the road better etc... does overcome the negative such as the neglectable mpg hit.

Even thou my vehicle has stock 18's, I'm still sticking with 18' because I don't want to go 19' - making sure enough tire wall is there for the potholes, if you get what I mean.

 

i dont feel a difference on my mpg after i upgraded to 19

 

feeling and knowing is 2 different things. There is alot of variables to MPG, such as how you drive, weather, road conditions, traffic, car maintenance, just to name a few. Unless you have a controlled condition for testing, you cant assume there is no difference.
Having more weight, especially unspung weight like wheels, tires, suspension components, hurts all aspects of performace like acceleration, braking, handling, and of course MPG.
Benifits? bling bling factor and maybe better road feel.

 

Somewhere I read that the stock 18's are somewhere around 28lbs each. As long as you shoot for rims within a couple pounds it shouldn't be that noticeable.

 

Cant really tell because some 19s are heavier than another.
You still probably loose couple miles to a gallon.