Does the Model V really get 2 MPG less?

The only "official" numbers I've heard of are on a UK Prius spec sheet (provided by another member--I've included it below).

For combined fuel consumption, the 17" wheel car gets 2.5% lower mileage (70.6 vs. 72.4).

2.5% of the combined EPA MPG of 50 is 1 MPG.

Honestly (he leads with his chin here... ) 2.5 % is a rounding error. Lots of other minor things that can have more of an effect on consumption. It wasn't even a consideration in my decision to get a Prius V. I suspect I may be in the minority here, though...

 

You can probably line up 10 random drivers with different levels from this forum and run a 50 mile test and none of them will be within 1 mpg of each other. 1 mpg less in 1 year of 12,000 miles of driving doesn't amount to 5 gallons of gas

 

It's literally a rounding error. The calculations are done in L/100km and rounded to 0.1L. All other countries in Europe use only the metric figure, we've botched our metric conversion so convert that figure to miles per (imperial) gallon for advertising purposes.

When you're down at 3.9L/100km, 0.1L is a surprisingly large percentage.

We still measure distance travelled in miles, and all signage is in miles, yards, feet and miles per hour, but we buy petrol in litres. Neither unit advertised makes any intuitive sense.

 

2mpg is what ... maybe 4% ??
In statistics jargon that means "it's about the same"

But it's pretty much a given, if/when you put bigger tire/wheel arrangements on a car (or the opposite ... smaller) you will affect mpg accordingly.

 

This accepted fact had its origins in a page from the chief engineers notebook, shown at the Detroit Prius Connection event, which appeared to indicate lower MPG for the 17" versus 15" tires, based on Toyota's own testing.

 

I Have a Prius V looking foward to taking so pictures. Prius is new to me I average 54 to 55 miles to a gallon. I guess it would be easier if we posted enough numbers between 15 and 17 in tires. To get an average we can better understand. I am happy with 50mpg or more thats why I bought the car!

 

Just like with the GII Prius, it's a tradeoff between tire traction (a 17" tire has a larger contact patch) and mileage. With the GII you also got shorter braking distances with the larger (16") wheels due to the better traction and I suspect that also applies to the GIII with 17" wheels.
The 17" wheel/tire combo is probably also a bit heavier, so you might get a little rougher ride. Most people wouldn't notice. Enthusiasts do.

 

??? I don't understand.unless you're in a panic stop and your ABS isn't working the wheels should not lose traction in a stop.

However if you simply mean it stops from 60mph in say 170 feet rather than 180 feet due to better traction then I'm till not sure how that would significantly affect regen.

Since most people trying to get regen while braking never really push the tires to their limit, then only under hard brakeing would you see any difference in stopping distances. And how often does that happen?

 

I drove a package III vs. V Wednesday night just to see if I could tell the difference between the 15 vs. 17 tires. Of course there are other things that affect the ride, but the V had a noticably stiffer ride. I'm not a car enthusiast or anything. Tighter in the corners, a little sportier feeling than the III. I actually liked the smoother ride of the III...I am not going for a sportscar...but my husband voted for the V and I suppose I should let him have a say at something.

 

Well that's about all I figured made sense as far as traction and stopping distance. But I don't see how that is going to affect regen unless it's they way one drives all the time. We all know that anticipating a stop and doing it gradually with the brakes transfers energy to the battery and if yout do it anywhere close to less than panic stops then it really doesn't matter if I have 17" or 15" wheels. From the moment I decide to stop at a light and apply my brakes, I'll have the same stopping distance regardless of my wheels.

 

The better stopping distance was obtained by testers. They lay on the brakes full power, on a smooth test track. Here the contact patch size is everything, along with the tire compound. It's not a real world test, but a test just the same, with results they can print and brag about. Real world testing is much more difficult and requires more intelligence, something lacking in car magazines.

Regen has nothing to do with braking distance. It's for those of us who drive efficiently.

 

Yes, by the Toyota engineers. However, the questions you need to ask yourself are:

1) Will I notice the tighter steering in the V over the other packages and does it matter to me? 3.75 turns lock to lock vs. 2.75

2) Am I willing to put up with the stiffer feel of the low profile tires and the louder tire noise?

3) Come winter (for those of us up north) since the V comes with a Summer performance tire, will I be willing to put on snows if deemed necessary?

The answer for us was that we were willing to take the slight penalty in fuel mileage for better handling.

 

AND 17" tires are quite a bit more expensive than 15" tires. Especially considering the small number of fuel efficienct tires available.

 

That's funny, My wife liked the V and I thought the better value was the III. I appreciate the quiet ride and don't mind the slower steering. She has been driving a Honda Civic Hybrid, which (she thought) handles better than the III.

 

Forgot that one! Yes, much less of a selection in replacement tires and more expensive to boot...

 

I undertand now. You really didn't meant this comment to have anything to do with the thread, which is does the 17" tires cost you 2 mpg. I couldn't figure out the relationship

 

Actually there is a wide selection of tires in this size, some reasonably priced (although not as cheap as 15"). Not sure they are low rolling resistance, but many have a 400+ tread wear rating.