bigger wheels = less fuel economy?

If I go from 16" wheels to 18" wheels, will I notice a difference in
fuel economy?

"The Devil's Advocate©" > wrote in message
...
> If I go from 16" wheels to 18" wheels, will I notice a difference in fuel
> economy?

Depends on the weight and also on if you correctly plus-size the tires or
not.

If you dont change the overall diameter of the tire/wheel combo, which you
shoudnt unless you also change the speedo gearing, and the weight of the
wheel/tire combos are the same, you should see no noticeable difference.

"The Devil's Advocate©" > wrote in message
...
> If I go from 16" wheels to 18" wheels, will I notice a difference in
> fuel economy?

>>"The Devil's Advocate©" > wrote in message
...
>> If I go from 16" wheels to 18" wheels, will I notice a difference in
>> fuel economy?

>If you dont change the overall diameter of the tire/wheel combo, which
you
shoudnt unless you also change the speedo gearing, and the weight of the
wheel/tire combos are the same, you should see no noticeable difference.
********
Unless you go wider then you'll get more rolling resistance & will loose
mileage - unless you go larger diameter & the car has enough torque to not
lug at whatever speed you're checking mileage at, in which case you *could*
get better mileage...
~ Paul
aka "Tha Driver"

Giggle Cream - it makes dessert *funny*!

If you keep the tire outer diameter the same, and wheel diameter goes up, and
everything else (width, mass, inertia of the tire/wheel assembly) remains the
same, you might make a case that your MPG would increase very slightly, albeit
immeasurably so. That change would result in the sidewall height decreasing,
resulting in less sidewall flex. And less flex is less energy dissipated in
the tire, i.e. less power wasted. Thats my guess anyway.

That's really a stretch here bringing tire flex into it. Look, your mileage
will essentially be the same if the outside diameter of the tire doesn't
change. Even if the diameter does change a little the mileage might appear
to change based on calculating it from your odometer but if your tire
(outside diameter again) is a different size than what came on the car you
won't be measuring actual miles - maybe more with smaller tires (outside
diameter) or less with larger tires (outside diameter). If your new tires
are wider there will be a greater contact area and more rolling resistance
which might reduce mileage a timy bit but this along with the weight of the
new wheels and tires compared to the original weights will only make a tiny
and probably imperceptible difference.

If you want to get into some big abstract theoritical quantum physics
analysis like how much the railroad track flexes when the fly lands on it or
how much the ocean level rises when you **** in it that's fine, but the
bottom line here is pay attention to the outside diameter of your tires
before making a change.




"DriveSpy" > wrote in message
...
> If you keep the tire outer diameter the same, and wheel diameter goes up,
> and
> everything else (width, mass, inertia of the tire/wheel assembly) remains
> the
> same, you might make a case that your MPG would increase very slightly,
> albeit
> immeasurably so. That change would result in the sidewall height
> decreasing,
> resulting in less sidewall flex. And less flex is less energy dissipated
> in
> the tire, i.e. less power wasted. Thats my guess anyway.

In rec.autos.makers.vw.watercooled, DriveSpy wrote:

>If you keep the tire outer diameter the same, and wheel diameter goes up, and
>everything else (width, mass, inertia of the tire/wheel assembly) remains the
>same, you might make a case that your MPG would increase very slightly, albeit
>immeasurably so. That change would result in the sidewall height decreasing,
>resulting in less sidewall flex. And less flex is less energy dissipated in
>the tire, i.e. less power wasted. Thats my guess anyway.

I like your analysis.

In article >,
Biz > wrote:
>If you dont change the overall diameter of the tire/wheel combo, which you
>shoudnt unless you also change the speedo gearing, and the weight of the
>wheel/tire combos are the same, you should see no noticeable difference.

Although if you choose tires with higher rolling resistance, you may lose
fuel economy from that. E.g. if your OEM wheels have something like OEM
Michelin Energy MXV4+ tires, you might find that most other replacement
tires (on OEM wheels or other wheels) have higher rolling resistance and
lower fuel economy.
--
------------------------------------------------------------------------
Timothy J. Lee
Unsolicited bulk or commercial email is not welcome.
No warranty of any kind is provided with this message.

That damn fly on the railroad track question is gonna bug me all night.

"Tom Levigne" > wrote in message
news
> That's really a stretch here bringing tire flex into it. Look, your
> mileage will essentially be the same if the outside diameter of the tire
> doesn't change. Even if the diameter does change a little the mileage
> might appear to change based on calculating it from your odometer but if
> your tire (outside diameter again) is a different size than what came on
> the car you won't be measuring actual miles - maybe more with smaller
> tires (outside diameter) or less with larger tires (outside diameter). If
> your new tires are wider there will be a greater contact area and more
> rolling resistance which might reduce mileage a timy bit but this along
> with the weight of the new wheels and tires compared to the original
> weights will only make a tiny and probably imperceptible difference.
>
> If you want to get into some big abstract theoritical quantum physics
> analysis like how much the railroad track flexes when the fly lands on it
> or how much the ocean level rises when you **** in it that's fine, but the
> bottom line here is pay attention to the outside diameter of your tires
> before making a change.
>
>
>
>
> "DriveSpy" > wrote in message
> ...
>> If you keep the tire outer diameter the same, and wheel diameter goes up,
>> and
>> everything else (width, mass, inertia of the tire/wheel assembly) remains
>> the
>> same, you might make a case that your MPG would increase very slightly,
>> albeit
>> immeasurably so. That change would result in the sidewall height
>> decreasing,
>> resulting in less sidewall flex. And less flex is less energy dissipated
>> in
>> the tire, i.e. less power wasted. Thats my guess anyway.
>
>