Ok some people have a misconception about tire sizes. Got this info. off the Tire Rack web. The 195/65/15 tire is 24.98 inches high: the the 205/55/16 are 24.88 inches high (this is a rare size) & the 215/45/17 tire are 24.62 inches tall. As you can see by these figures the 15 inch rim tire is taller than the other two by a small margine. The differance is so small that it won't effect the speedometer. All your going to get with the 17 inch is the tire side wall is not as tall as the 15 inch, there for the tire will be stiffer. The short sidewal is hard riding and may be more subject to a blow out in a pot hole.:rockon:
Kenny is right. When people go to larger rims they usually keep the same diameter tire. The effect is mostly cosmetic. More alloy and less tire, is the look the KIDZ are going for these days.
I did the research when I went to 15 inch for snow tires. your speedometer is based on revolutions per mile, which is dependent on the specific tires (you can get the info from the manufacturers websites or tirerack.com). You can do the math yourself, but there are also many websites that will do it for you. The bottom line is that moving up to the OEM Michelin 17 inch tires would cause your speedometer to read about 1 mph higher than true speed at 65 mph -- not much, but it is measurable. As many people have noted, your speedometer is already reading high, so the 17 inch tires would compound that. (by moving down from 17 to OEM 15 inch size, by speedometer would be more accurate in the winter). To reduce the speedometer error, you could use non-OEM size 17 inch tires (different width or profile) to one that has a closer circumference. Again, there are website that can help (including tirerack.com). Also, if you have nav, you would want to make sure you recalibrate for the different tires.
I highly recommend against the 215/45/17, they are just too small and make the car look a little r...... I ended up with 205/50/17 as the diameter is closer to the stock 195/65/15
Cossie, do you have any pics of the new wheels and tires on the car? After researching I was thinking of the same size tires you are suggesting but would like to see them on the car.
Don't forget the extra 2 cm of tire width will shorten stopping distances. Also the stiffer sidewalls and extra width mean better handling. There is more to it than looks, 17" wheels and 45 series tires are not out of line for a car the size and weight of a Prius. I agree when changing tire and wheel sizes it is best to stay within a couple of percent of the revolutions per mile. FYI my car came equipped with 215/45-17 tires and my speedometer error is about 2 MPH at 70 MPH according to the speedometer, the speed displayed by the scan gauge is right on according to my portable GPS receiver.
205/50/17 looks a little too fat for my taste, but it may be a better size for those with II-IVs upgrading to 17" wheels due to the different steering ratio.
BTW, during my research I found this tool Wheel / tire size calculator / comparer - WWW.RIMSNTIRES.COM that might help visualize different wheel and tire parameters....
17x7. I chose 205 over the 215 simply for the fact that the car looks stupid with the 215/45/17. The car didn't have enough tires for the long suspension and big body. Ride didn't get worse with the Hankook Ventus V12, nor did it make more noise or have any noticeable drop in fuel economy. It just looks better than the 15" IMO. Total cost was like $700 for the rims and a set of new tires.
Difference in sidewall height between a 205/50 and a 215/45 is only 5.75 mm, less than a 1/4 of an inch. Is it really that noticeable?
According to the link in post #10, the overall diameter is 12 mm (~half an inch) taller. Can't you tell from cossie's picture that the tires look fatter? The fatter tires make the rims look smaller IMO.
