Toyota Ethical Question

I suspect that, under government regulations, Toyota has no discretion to put a different window sticker on a Prius V, even if it wanted to do so.

 

I was thinking a lot about this too and was wondering why despite that statement, the estimated fuel economy remained the same for all models. I wonder if it has anything to do with the LED headlights having less electrical consumption? Would 30% less electrical consumption there average things out on the whole? I don't know.

 

Not really. I'm pretty sure the mileage is close enough to fit within the margin of error the EPA allows. My experience with a IV is that I regularly exceed the EPA estimates, I would assume the V would just be closer, all other things being equal.

BTW, I don't buy the weight being the issue re: any delta in mileage. I suspect that the smaller overall diameter of the 17" option slightly increases engine RPM per given MPH, resulting in perhaps slightly less overall MPG. I haven't really noticed much if any difference in MPG when I carry a passenger, which would dwarf the few pounds extra the wheels might weigh.

 

Many people with Vs are posting MPGs significanly higher than the EPA estimates for the 2010 prius. I think the mileage you get will depend on how you drive the car moreso than which model you choose.

 

The real question is, which model did Toyota supply for EPA testing? Most pre-release mules seemed to either be IV or V models, so it may be that the published mileage is the worst one, and it just gets better as the car gets lighter.

EPA allows for some variation on a model line without requiring re-testing or re-statement.

 

I doubt that 17" wheels will make the mpg 2-4 mpg less?

Why would they? They present a tiny bit more frontal area, and a slightly bigger foot print,and maybe 3-4 lbs more per wheel/tire in weight.It certainly shouldn't add up to 5to 8% poorer mpg?

Lots of vehicles have bigger tire/wheel combos but the same EPA. If it was a truck with heavily lugged tires, yes,I could see a big mpg hit, but not on a car with car tires. Besides, the shorter sidewall should actually decrease rolling resistance a little since it flexes a bit less.Of course the wider footprint, and slightly increased frontal area and weight will more than negate that. Taller wheels tires should have less rr for other reasons-same reason 10" tires aren't as efficient as 15' tires.

Charlie
PS Buy the shorter tire/wheels(cheaper to replace the tires and slightly better mpg)

 

As far as I know, there is only 1 EPA MPG estimate done per car model, even though there are typically numerous options/packages available. An extreme example would be Porsche--for any given model, there are hundreds of option combinations, but they only have 1 EPA MPG estimate per model.

Sure, the 17" wheels--being heavier--will impact MPG. Likewise with the solar roof--should there be a separate MPG estimate for cars with solar roof? But as previously noted, it could be considered a rounding error in the EPA testing.

I'm sure all manufacturers--and not just Toyota--use the most advantageous configuration for the EPA tests.

 

And who has really proven the "hit" will be as large as some has stated by doing a direct hear to head comparison?

 

I wouldn't blame Toyota. In theory, just about any option could affect mileage, from heavier seats to a better stereo. Even the drag coefficient will change according to how dirty your car is. Testing is expensive, and it's not reasonable to expect a precise figure for each and every permutation. As they say, your mileage may vary. It's already better than just about anything else you can buy, and it will get better still as you learn to drive it.

 

Practically every car model comes with various rims and the like ... so it's not like they're doing anything anyone else isn't doing.

I am getting 2-4 mpg better than I did with my '08 Touring ... or so. I think I can do better than that though b/c I have been playing with PWR mode quite a bit

 

The reduction in mpg between 15 and 17 inch wheels is published on the UK tech spec:

w-w-w-toyotagb-press.co.uk

(I cant post URLs till Ive done 5 posts....!)


17 inch rims - combined = 70.6 mpg
15 inch rims - combined = 72.4 mpg

hope this helps

Lex

 

You do realize that if you drive an average of 10,000 miles a year and lets say you get 50 MPG, with the 15" wheels, you will burn 200 gallons of gas annually, and lets say that fuel costs $3.00 a gallon, your annual fuel expense is $600 for a full year's fuel consumption. Now, using those same parameters, lets say you drive that same 10,000 miles, but, instead of 50 MPG with the 15" wheels, you only get 47 MPG with the 17"s (the average between a 2-4 MPG loss). This results in a net savings of $38.30 (again, at $3.00 a gallon) for that entire year's driving with 17"s as opposed to 15"s.

Only you can decide if the 17" wheels and tires on the V are worth less than $39 a year in EXTRA in fuel expense! However, if you'll read the posts in this forum, it seems representitive to me that most of those reporting their milage with IIs, IIIs and IVs (all equipped with 15"s) are getting 53-58 MPG, and those with Vs (the only model equipped with 17"s) also seem to be getting that same mileage (53-58 MPG)!

I'm not convinced Toyota would want to alarm potential buyers over a relatively insignificant difference in both MPG and cost differences.

David (aka Blind Guy)

 

So that's a 2.5% difference--perhaps $15 - $20 per year in gas cost--sounds like a rounding error to me.

 

The only cars that have to be re-tested are ones with different powertrains. Chnage the engine, transmission, or the amount of wheels turning and you have to re-test. Equipment makes no difference to the EPA.

And you can blame the EPA for it though. It is their rules, not Toyota's. If you think about it, imagine the costs involved in testing each car based on the different options. Technically, ANYTHING you add to the vehicle will cause a weight difference ergo a fuel mileage decrease.

From the time I started in this business, I always tell customers that the number on the sticker is an estimate. There are so many factors involved besides what engine or wheels are on a car that will effect mileage. People here prove it everyday.

 

Going from 15" to 16" Touring wheels resulted in less mpgs for the GenII, so it is reasonable to believe that a jump from 15" to 17" for the V would also result in a slightly lower mpg.

 

Here's the more in depth differences (based on UK gallons & miles)

 

While the 17 inch wheels alone are probably heavier and may impact MPG, there may be other features on the V that mitigate that extra weight or otherwise benefit the V in the EPA testing. After all, all models are listed as having the same curb weight. For example, is it possible that the leather seats in the IV and V are structurally different and weight less than the cloth seats? I don't know. And I believe the V has a slightly different steering system that I guess could be lighter. I also wonder if the V has the more efficient LED lights for a reason, such as exploiting the EPA protocols. That is, is it possible that headlight usage is required in the EPA testing and the lower power LED's would help the V's numbers?

Just my quick thoughts....

 

I've noticed 17" wheels are usually wider, so have a larger tire patch contacting the road. If this is true for the Prius V, then roll resistence would likely be the major contributor to any decrease in MPG.

Weight increase effects on milleage would be reduced on this car due to the regenerative braking. That extra weight/mass = kinetic energy which is recouped, just like the rest of the mass of the car. Of course there's a loss of energy. Anybody know the efficiency of the regenerative braking?