Toyota Ethical Question

I also noticed this when the brochures were released but assumed that the mileage estimates fall within the EPA regulations. A quick look at the Ford Hybrid Fusion brochure basically does the same thing... they have custom accessory wheels available but only provide one EPA figure with the original wheels.

 

I know that on Lexus vehicles there is a disclaimer on the literature and on the windows that choosing larger wheel diameters will significantly affect tire treadwear. I wouldn't be surprised if they eventually came out with a sticker for the Prius V as well.

I've never seen another carmaker make such a disclaimer...

 

I'm not so sure it would be a larger patch but maybe just a wider patch, which would still affect the resistance

 

wider =

1) more patch therefore more friction (rolling resistance)
2) more air resistance (increased cd)

but as said above $38 dollars per year

 

Toyota isn't to blame at all. The EPA sets the testing protocol, and in this case it publishes one figure for all of the models.

Tom

 

The weight of the wheels and tires, and the width and rolling resistance of the tires all affect gas mileage.

When Consumer Reports tested the Gen II Touring Edition with its 195/55R16 tires and the Standard Prius with its 185/65R15 tires, it found that the Touring Edition averaged 2 fewer mpg than the Standard Prius.

My bet is that the 2010's 17" wheel model with its 215/45R17 tires will average at least 2 fewer mpg than the 2010's 15" wheel model with its 195/65R15 tires.

 

At the Toyota Owner Appreciation Dinner, Toyota reps specifically stated there was a goal to keep all models within the same EPA estimated mileage, which was why Model V cannot have the Solar Moon Roof. Apparently, there is som range they can stay within and keep one EPA rating for the whole line.

 

I agree with Boo.

Having done the 15" to 17" swap over and over again on my 2005 I see an instant drop in MPG every time I put the 17s back on. To be fair the 17" tires are not low rolling resistance rated and they are generally more of a performance tire BUT the 17" wheel sare very light and nearly comparable to the stock 15" wheels.

So many of you can theorize all you want but every person on this forum that has put in a decent amount of effort in analyzing the difference between their stock 15" combo and their aftermarket 17" combo has noticed a decrease in MPG. With the intoduction of fuel saving tires in the 17' range this should help regain some lost MPG but on the other hand, those same tires in a 15" size will yeild better MPG.

http://priuschat.com/forums/gen-ii-...g-back-stock-rims-testing-mpg-difference.html

 

Maybe that's why they are called EPA Mileage Estimates?

 

To address the question of 'ethics', I would say Toyota is being completely ethical by following the EPA guidelines and legal requirements.
And other car manufacturer handles this the same way. Heck, look at the brochure for a Ford F-350. I could find NO mention of fuel efficiency at all. And no mention of a change with the optional second SET of tires on the back axle.
While I agree more information is good, I see no reason to pick out Toyota if asking if this behavior is unethical.

 

i think that vehicles NOT posting the EPA numbers is because they exceed the weight category. for example, i once asked HUMMER salespeople at the car show about the mileage being absent and they said that it exceeded the weight limits. when i pressed harder, they finally told me to expect about 5-9mpg. wow. i just walked on.

 

its been so long since i have driven anything else, i dont really remember but did the EPA publish different figures for automatics and manual tranny cars?

also, 17" wheels being shorter, are softer to cushion the ride so rolling resistance will be higher. the actual diameter difference is nearly negligible with rotations per mile between the two tires only varying by less than 5?? (dont remember exact figures but it was like 534 to 538 or something like that)

what is the weight difference between them? mine says 2985 on the title. 3820 is gross weight on door. in comparison, the SPM says 2830 on the title... so 155 lbs heavier, faster, bigger, still better gas mileage...

 

Most definitely. Usually a 2 mpg hit for the automatic.