Icncrease MPG with taller tire

It's not that simple. Larger diameter does not equal higher milage. If it did, all those SUVs on the 25-in hoops would be getting a zillion MPG. Also, there isn't a known way to recalibrate the MFD for a different diameter tire. (Although Prius is sold with different wheel options in Japan and Europe so it might be buried somewhere in the service menus, but we just haven't found it.)

 

The Prius is desigigned to tell you you are going a little faster than you really are so putting on taller tires might actually make the speedometer more accurate while the Odometer will be a little slower.

 

Got to be careful about trying this though. The rear wheel well might not be able to properly fit though. The larger tires could rub the rear wheel well when making turns.

 

<div class='quotetop'>QUOTE(benighted @ Apr 4 2006, 09:01 PM) [snapback]235151[/snapback]</div>

Wow, this is like setting my alarm clock five minutes ahead so I won't be late in the morning. Problem is, I always know I've set it ahead, so it never really works.

How much faster does the Prius speedometer say you're going than your actual speed?

 

<div class='quotetop'>QUOTE(benighted @ Apr 5 2006, 03:01 AM) [snapback]235151[/snapback]</div>

There must be something wrong with mine. When I check it with a WAAS enabled GPS on a straight road (GPS accuracy +/- .05 mph) my 2006 seems to be exactly correct within rounding to the nearest whole mph number (that is, 45 mph rather than 44.5 through 45.4).

OEM tires at 40/38.

If you want to play with tire size changes, a good calculator showing mph variation from standard is at http://www.miata.net/garage/tirecalc.html . Note that normally putting on larger wheels is done with a lower profile tire so that the effect on your speedometer and odometer accuracy is little to none.

- Tom

 

<div class='quotetop'>QUOTE(etyler88 @ Apr 4 2006, 09:33 PM) [snapback]235039[/snapback]</div>

You're not the only one looking at it - a number from the TDI crowd have done likewise. One went from the OEM 205-55-16 to 205-60-16, and I'm looking at taller tires as well.

 

<div class='quotetop'>QUOTE(etyler88 @ Apr 5 2006, 11:33 AM) [snapback]235039[/snapback]</div>

Do you know how a final gear ratio is selected?
And, do you know why does Toyota set it 4.113 for Prius?

No, the spedometer can't be adjusted.

Ken@Japan

 

<div class='quotetop'>QUOTE(Red Ginger @ Apr 5 2006, 02:43 AM) [snapback]235180[/snapback]</div>

mine runs about 3 to 4% over actual speed

 

<div class='quotetop'>QUOTE(benighted @ Apr 5 2006, 03:01 AM) [snapback]235151[/snapback]</div>

:huh: Huh??? The Prius is desigigned to tell you you are going a little faster than you really are ..
Umm what is that again?

Lets see the speedo reads 45mph, per the stalker radar clock the cars doing 45mph. So the radar gun is telling the user your going faster than you are..?.. :blink: :wacko:

I put the taller tires on my 04 what a mistake, it now tells me in getting worse mpg's ....


Sounds like someone needs thier speedo recalibrated..

I know most cars can be off by 2-5 mph slower or faster but this can be fixed by recalibration not sure if the prius can be done though..

 

<div class='quotetop'>QUOTE(etyler88 @ Apr 6 2006, 04:22 AM) [snapback]235407[/snapback]</div>

So...
What kind of technology are you talking about in your theory?

Ken@Japan

 

<div class='quotetop'>QUOTE(priusguy04 @ Apr 5 2006, 07:16 PM) [snapback]235626[/snapback]</div>

<div class='quotetop'>QUOTE(ken1784 @ Apr 5 2006, 12:14 PM) [snapback]235402[/snapback]</div>

 

IF the SPEEDO is off so will the ODO be off, so doing MPG with paper and pen will not be accurate.

Only way I know would be to drive exact course that you already know, and calculate MPG based on that when filling up.

 

<div class='quotetop'>QUOTE(BVISAILMAN @ Apr 10 2006, 12:43 PM) [snapback]237648[/snapback]</div>

Not necissarily.
Can manufacturers can make the ODO accurate while inflating the MPH on the SPEEDO.

 

I might be wrong, but dosen't it take more horsepower to turn bigger wheels? Accelerations might be slower, the indicated speed would be slower, and the indicated MPG would be less.

Kaos1