16" Wheels

You've got a good grasp of the basics here, but your conclusions are incorrect. The contact patch and mu-slip curve of the tire are equally critical for control of ABS, TCS, VSC, etc. specifically because the amount of hydraulic pressure change (translated to frictional change) needed to decelerate or accelerate the wheel for a given vehicle speed and wheel slip depends on the response of the tire/road interface. This is not a binary thing. It may seem like it could be, but maintaining slip at a near constant level requires a system response closely tailored to the response of the system. VSC is equally critical since the amount of time and pressure for which a specific wheel is braked to correct an undesired trajectory again depends on the system response. Yaw control is also a common feature of most ABS systems now in production. Without calibrating to the system response, ABS could have a loss of steering while braking and stopping distances would generally increase. For TCS, high slip levels could damage differentials and low slip levels could greatly reduce acceleration. For VSC the response could undercorrect or overcorrect, resulting in the continuation of or the creation of a skid condition. The US version drum brake response is likely much different than the Euro rear disc response.

There is a lot of work done to try to generate robust systems which can handle different versions of the same model, which often have different wheels, tires, engines, and transmissions. However, this ability is limited, and there is certainly no generic "one works for all" ABS or TCS or VSC setup. Development and testing is not done for non-OEM specified tires or tire sizes. This I know for sure, as I am specifically in this business for a living and have been doing it since the mid 80's. The only way to know for sure if there are different calibrations used for different models or options is to either verify the brake controller ECU part number is different, or have an inside information source who can tell you if the car "learns" its configuration through other boxes, such as the powertrain controller or body computer, and selects the correct calibration tables based on this finding. In these cases, unless the corresponding box is changed to indicate the new configuration (such as Euro with disc vs US with drum) the wrong calibration tables will be used and performance will suffer.

 

Has anyone convinced their dealer to sell a car with 16" wheels, thereby avoiding the extra-set-of-wheels problem?



Cost?

 

Well, I don't really care if they are the same as the Euro wheels, so long as they're nice. Not having done this, will I be better just doing it retail and then finding an outlet for teh old wheels, or will the dealer actually discount the new wheels by the old wheels?

 

I’ve been reading numerous posts on tire and wheel size with interest. Having equipped numerous vehicles with +1, +2, and +3 tire and wheel combinations, I’ve come to the conclusion that size does matter, as does looks.

Numerous tire sites list tire and wheel package options all the way up to 18†wheels. I am currently looking at Akuza AKA 218 Sublime wheels (chrome) 17x7.5, and Toyo Proxes FZ4 215/45ZR17 All-Season tires. This package has been tested and installed on a CA 2004 Prius in Nor Cal (www.bigwheels.net). Bigger size rims come with lower profile tires, so the overall tire diameter remains the same as your original tires.

All arguments aside, the look and the feel of less flexible rubber under the car is worth it.

NVHERKNAV
Reno, NV.

 

Why settle for 16's..... 17" Wheels Look Much Better

I've gone to 17x7.5" Arelli Assassyn's with 205/40R17" Nankang's all the way around and I have no regrets yet. Better handling and stopping. No more wandering and gas mileage isn't affected as much as I suspected ( no more than four or five-ish) and they SURE look better - to me at least.

Outside total diameter is identical to the OEM setup. No changes to speedometer or odometer or NAV.

 

What should I get for winter wheels/tires?

 

the difference in mileage is not .1%

the circumference of a circle is 2*3.14(Pi)*R (radius) or Pi*diameter.

so the 15 in wheel would roll 47.12"
the 16" wheel would roll 50.27"

as you can see that would be 6% greater distance. which is significant in
my book. BUT

we would also need to take into consideration the amount of energy
needed to rotate the wheel. and the greater the radius, the more
energy is required to rotate that wheel at a given velocity.

look at it as leverage in reverse which it is. the longer the handle, the
more turning power exerted at the point of rotation. Conversely, the
longer the handle ( or the greater the diameter) the greater the amount
of energy necessary to make the wheel turn. so the loss of efficiency
can be partially attributed to additional torque required to turn the bigger
wheel.

now for the low profile tires, if the diameter doesnt change, then the
mileage shouldnt change. or at least the change would be the result
of the differences in the rolling resistance of the tires etc.

 

I agree htmlspinnr, these 17'' wheels are just HORRIBLE. [Broken External Image]:http://www.smailiki.nm.ru/med/med_54.gif

100% Kitsch.

Owner of such a car should be promptly sterilized to prevent further breeding of such a tasteless specie.

 

Your analysis is incorrect. You have correctly calculated the wheel affect, however the total diameter is the wheel plus the tire. The increased wheel diameter is offset by the smaller diameter, or lower profile, tire that is used (smaller aspect ratio). Thus the rolling radius is unchanged from the 15 inch setup if you choose the correct tire size.

 

mdac:

your analysis of my analysis is incorrect and incomplete.

you conveniently skipped this part of my post.

now for the low profile tires, if the diameter doesnt change, then the
mileage shouldnt change. or at least the change would be the result
of the differences in the rolling resistance of the tires etc.

also my post was in response to the guy who stated that the change in diameter would only cause a .1% change in rolling distance.

as for your argument... see bolded text above.

 

Interesting....your last two paragraphs did not appear when I responded. My comments are thus invalid.

My apologies.

 

hey no problem....

i have been guilty of overlooking posts also.
but it does raise an interesting possibility. i kinda
remember the post in question being one where i hit
the enter button by mistake and then had to edit it.
the edited part would have been something added on
at the end and i wonder if for some reason that part
didnt show up for you. the edit would have happened
several hours before your post though so maybe it
didnt have anything to do with it. but i have
discovered several times in the past that when dealing
with computers, nothing should be ruled out.

 

If someone wants fancy wheels (without compromising on taste), that's the way to go, I beleive: