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grampi
06-03-2007, 09:56 AM
Since a lot of folks are interested in going with "plus" size tires and wheels, I thought I'd post the overall diameter of some of the more popular sizes, along with the OEM sizes.

OEM

175/65/14 = 22.92"

185/60/15 = 23.7"

Plus sizes

195/50/16 = 23.64"

205/45/16 = 23.23"

205/50/16 = 24.03"

205/45/17 = 24.23"

205/40/17 = 23.43"

What has me a bit puzzled is the disparity between the two OEM sizes. That's .8" difference in overall diameter, which is quite a bit. You'd think Toyota would've wanted those two numbers a bit closer together.

I have narrowed my chioces down to to either 16" or 17" wheels. If I go with 16s, my tire size will probably be 205/45/16. If I go with 17s, my tire size will probably be 205/40/17. I was also considering 195s until I saw what a poor selection of tires are available in that size. The best selection is in the 205 size.

I haven't decided between 16s or 17s, and I really don't know what factors are going to help me with this decision. The number of tire chioces are roughly the same in both sizes. I may be leaning toward the 16s as their somewhat taller sidewall may offer a bit smoother ride, but am I really going to be able to tell the difference between a 45 and a 40 series tire in terms of ride comfort? Both have very short and stiff sidewalls.

If anyone would like to do their own figuring, here's the formula:

tire width * aspect ratio * 2 / 2550 + wheel diameter = overall diameter

or

205 * 45 * 2 / 2550 + 16 = 23.23"

brickhardmeat
06-03-2007, 10:47 AM
am I really going to be able to tell the difference between a 45 and a 40 series tire in terms of ride comfort?

yes

grampi
06-03-2007, 12:02 PM
am I really going to be able to tell the difference between a 45 and a 40 series tire in terms of ride comfort?

yes

Care to expound a bit?

SailDesign
06-03-2007, 12:12 PM
If anyone would like to do their own figuring, here's the formula:

tire width * aspect ratio * 2 / 2550 + wheel diameter = overall diameter

or

205 * 45 * 2 / 2550 + 16 = 23.23"

Make that 2540, not 2550, so the final diamater is 23.26", and you've nailed it!

Or - just use the spreadsheet to compare sizes

Doc Zaius
06-03-2007, 12:25 PM
Or check out the first couple posts of the Official Tire guide (http://www.yarisworld.com/forums/showthread.php?t=5021)... this has been talked about.

brickhardmeat
06-03-2007, 01:27 PM
Or check out the first couple posts of the Official Tire guide (http://www.yarisworld.com/forums/showthread.php?t=5021)... this has been talked about.


yeah see the official tire guide

and you -will- feel a difference from 45 down to 40

I'm very please with a 205/50/15

I also like using this for comparisons ...http://www.miata.net/garage/tirecalc.html

grampi
06-03-2007, 01:29 PM
Make that 2540, not 2550, so the final diamater is 23.26", and you've nailed it!

Or - just use the spreadsheet to compare sizes

According to this it's 2550:

http://oly4x4.com/metrictireconv.htm

grasshopper
06-04-2007, 05:03 AM
Sail is right. 1 inch = 25.4mm. so the height formula should use 2540. But, 3/100" discrepency is nothing to cry about.