Prius MPG vs Tire Size

"Jeff Strickland" <crwlr.DeleteThis@verizon.net> wrote in message
news:efh7k.262$zE6.145@trnddc02...
> Mileage is more a function of the overall tire size than the size of the
> rims.
>
> A 225/55x15 and a 225/45x17 are within a quarter inch (appox) of being the
> same overall size. The affect on mileage is insignificant.

According to the Toyota website, these are the available wheel/tire sizes
for the 2008 models:

P185/65R15
P195/55R16

According to this website, the 15 inch wheel/tire combination is 1/10 of an
inch larger diameter than the P195/55R16.
http://www.miata.net/garage/tirecalc.html

The 16 inch tire (because it is wider) will theoretically have more rolling
resistance and be less efficient, but will have better handling and braking.
 >> Stay informed about: Prius MPG vs Tire Size 

On Jun 21, 7:36 pm, "FMB" <f... DeleteThis @sbcglobal.net> wrote:
> I see the Prius 4dr Touring Hatchback is available with 16" Standard and 17"
> & 18" available as Optional wheels/tires.  I'm guessing the larger the tire,
> the more comfortable the ride.  How bad a hit on the MPG does the car take
> when using 18" as opposed to 16" wheels/tires?
>
> FMB
> (North Mexico)

A smaller tire should be better, years ago I went up about 5 sizes on
a big 4x4 and lost maybe 20% milage, original tires on it were
undersized. But weight is a big factor, I would think toyota would
know exactly how much different
 >> Stay informed about: Prius MPG vs Tire Size 

On Jun 22, 9:57 am, Retired VIP <jackj.extradots.....RemoveThis@windstream.net>
wrote:
> On Sun, 22 Jun 2008 07:44:28 -0700 (PDT), ransley
>
> <Mark_Rans....RemoveThis@yahoo.com> wrote:
> >On Jun 21, 7:36 pm, "FMB" <f....RemoveThis@sbcglobal.net> wrote:
> >> I see the Prius 4dr Touring Hatchback is available with 16" Standard and 17"
> >> & 18" available as Optional wheels/tires.  I'm guessing the larger the tire,
> >> the more comfortable the ride.  How bad a hit on the MPG does the car take
> >> when using 18" as opposed to 16" wheels/tires?
>
> >> FMB
> >> (North Mexico)
>
> >A smaller tire should be better, years ago I went up about 5 sizes on
> >a big 4x4 and lost maybe 20% milage, original tires on it were
> >undersized. But weight is a big factor, I would think toyota would
> >know exactly how much different
>
> Did you recalibrating your speedometer/odometer?  Increasing the tire
> size will make the speedometer read slow and the odometer read shorter
> than the distance traveled.
>
> All other things being equal, larger diameter tires should result in
> reduced rolling resistance and give slightly better mileage.
>
> Jack

Larger tires have more rotational mass that takes more energy to get
moving and slow down, larger tires change the gearing both will loose
you mpg as you will never see the real large tires as an option as you
do on other makes, larger tires lost me alot of mpg, pickup, and
braking, best mpg would be a thin tire with hard compound.
 >> Stay informed about: Prius MPG vs Tire Size 

On Sun, 22 Jun 2008 07:44:28 -0700 (PDT), ransley
<Mark_Ransley.DeleteThis@yahoo.com> wrote:

>On Jun 21, 7:36 pm, "FMB" <f....DeleteThis@sbcglobal.net> wrote:
>> I see the Prius 4dr Touring Hatchback is available with 16" Standard and 17"
>> & 18" available as Optional wheels/tires.  I'm guessing the larger the tire,
>> the more comfortable the ride.  How bad a hit on the MPG does the car take
>> when using 18" as opposed to 16" wheels/tires?
>>
>> FMB
>> (North Mexico)
>
>A smaller tire should be better, years ago I went up about 5 sizes on
>a big 4x4 and lost maybe 20% milage, original tires on it were
>undersized. But weight is a big factor, I would think toyota would
>know exactly how much different

Did you recalibrating your speedometer/odometer? Increasing the tire
size will make the speedometer read slow and the odometer read shorter
than the distance traveled.

All other things being equal, larger diameter tires should result in
reduced rolling resistance and give slightly better mileage.

Jack
 >> Stay informed about: Prius MPG vs Tire Size 

"ransley" <Mark_Ransley.DeleteThis@yahoo.com> wrote in message
news:891336de-dccb-4be7-9ff4-a81bdabdbec9@j22g2000hsf.googlegroups.com...
On Jun 21, 7:36 pm, "FMB" <f....DeleteThis@sbcglobal.net> wrote:
> I see the Prius 4dr Touring Hatchback is available with 16" Standard and
> 17"
> & 18" available as Optional wheels/tires. I'm guessing the larger the
> tire,
> the more comfortable the ride. How bad a hit on the MPG does the car take
> when using 18" as opposed to 16" wheels/tires?
>
> FMB
> (North Mexico)

A smaller tire should be better, years ago I went up about 5 sizes on
a big 4x4 and lost maybe 20% milage, original tires on it were
undersized. But weight is a big factor, I would think toyota would
know exactly how much different


That's a huge jump in size, and you changed the overall diameter without
altering the gear set.

The available tire sizes for the Prius are the same overall diameter, and
this would make the only difference be the width of the tire, and the affect
this would have on the rolling resistance. I suggest the affect of a 185 and
a 195 would be insignificant, and the improvement to handling would offset
any negative affect that the rolling resistance might create.
 >> Stay informed about: Prius MPG vs Tire Size 

"Jeff Strickland" <crwlr RemoveThis @verizon.net> wrote in message
news:BKv7k.761$IL6.197@trnddc04...
> That's a huge jump in size, and you changed the overall diameter without
> altering the gear set.
>
> The available tire sizes for the Prius are the same overall diameter, and
> this would make the only difference be the width of the tire, and the
> affect this would have on the rolling resistance. I suggest the affect of
> a 185 and a 195 would be insignificant, and the improvement to handling
> would offset any negative affect that the rolling resistance might create.

Both the Prius models that have P185/65R15 (regular model) and P195/55R16
(touring model) have the same EPA mileage rating.
 >> Stay informed about: Prius MPG vs Tire Size 

"Mark A" <nobody DeleteThis @nowhere.com> wrote in message
news:Y%w7k.9029$AJ6.8739@bignews8.bellsouth.net...
> "Jeff Strickland" <crwlr DeleteThis @verizon.net> wrote in message
> news:BKv7k.761$IL6.197@trnddc04...
>> That's a huge jump in size, and you changed the overall diameter without
>> altering the gear set.
>>
>> The available tire sizes for the Prius are the same overall diameter, and
>> this would make the only difference be the width of the tire, and the
>> affect this would have on the rolling resistance. I suggest the affect of
>> a 185 and a 195 would be insignificant, and the improvement to handling
>> would offset any negative affect that the rolling resistance might
>> create.
>
> Both the Prius models that have P185/65R15 (regular model) and P195/55R16
> (touring model) have the same EPA mileage rating.
>
>

.... which confirms my suggestion that the difference would be insignificant.


Width in Millimeters 185 195
Aspect Ratio 65 55
Rim Size 15 16
Tire Diameter 24.469 24.445
Tire Circumference 76.870 76.796
Revs / Mile 824.249 825.045
Width in Inches 7.283 7.677
Sidewall Height 4.734 4.222


As you can see, the difference in Revs Per Mile is less than 1.
 >> Stay informed about: Prius MPG vs Tire Size 

"Jeff Strickland" <crwlr DeleteThis @verizon.net> wrote in message
news:1LB7k.5902$JL.3461@trnddc05...
>
> "Mark A" <nobody DeleteThis @nowhere.com> wrote in message
> news:Y%w7k.9029$AJ6.8739@bignews8.bellsouth.net...
>> "Jeff Strickland" <crwlr DeleteThis @verizon.net> wrote in message
>> news:BKv7k.761$IL6.197@trnddc04...
>>> That's a huge jump in size, and you changed the overall diameter without
>>> altering the gear set.
>>>
>>> The available tire sizes for the Prius are the same overall diameter,
>>> and this would make the only difference be the width of the tire, and
>>> the affect this would have on the rolling resistance. I suggest the
>>> affect of a 185 and a 195 would be insignificant, and the improvement to
>>> handling would offset any negative affect that the rolling resistance
>>> might create.
>>
>> Both the Prius models that have P185/65R15 (regular model) and P195/55R16
>> (touring model) have the same EPA mileage rating.
>>
>>
>
> ... which confirms my suggestion that the difference would be
> insignificant.
>
>
> Width in Millimeters 185 195
> Aspect Ratio 65 55
> Rim Size 15 16
> Tire Diameter 24.469 24.445
> Tire Circumference 76.870 76.796
> Revs / Mile 824.249 825.045
> Width in Inches 7.283 7.677
> Sidewall Height 4.734 4.222
>
>
> As you can see, the difference in Revs Per Mile is less than 1.

Thank you all for your input. I appreciate it.

FMB
(North Mexico)
 >> Stay informed about: Prius MPG vs Tire Size 

On Jun 22, 9:18 pm, "FMB" <f... DeleteThis @sbcglobal.net> wrote:

>
> > As you can see, the difference in Revs Per Mile is less than 1.
>
> Thank you all for your input. I appreciate it.
>
> FMB
> (North Mexico)

The use of low rolling resistance tires will make quite a bit
more difference than the small change in size.
IE: the goodyear integrity is a low rolling resistance tire..
That's why they use em on a lot of the new cars..
Helps them squeak through the gov regs on mpg..
The Corolla uses the same exact tires.. Same size too..
So when I get new tires, which happens to be soon o-clock,
I'm going to stick with low rolling resistance tires.
I really do think they make a difference. IE: my corolla
will coast a real long way vs some cars/tires..
I think the tires play a fairly large part in that.
I've heard a low resistance tire can have 20-30% more
drag than some other regular type tires.
Which in the real world may mean 2-3 mpg extra.
No matter what you run, the higher the pressure, the
lower the rolling resistance.
Although the integrity gets some pretty lukewarm reviews,
I might stick with em, just to keep the low resistance.
And, actually I haven't really had any particular trouble
with them. I'm clocking over 43k on the original set and
they are still going. They will cost me about $30 bucks
a tire more than a cheapy $60 special, but I hear the
cheapy tires can really jack the resistance up a bit.
I've read reviews at tires.com from some drivers that
actually noticed the difference in mpg and commented
on it.
 >> Stay informed about: Prius MPG vs Tire Size