# Tire size calculators **URL:** \ **Category:** SON240sx Automotive\ **Created:** [December 1, 2008, 3:14pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260 "2008-12-01T15:14:52Z")\ **Posts on this page:** 16\ **Page:** 1
**Author:** ![bing](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/bing/32/7211_2.png) [@bing](https://forums.speedlife.net/u/bing)\ **Post date:** [December 1, 2008, 3:14pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/1 "2008-12-01T15:14:52Z")
so my wife’s car has 205/60/16" tires on it and i want to know how much different the sizing is on a set of 205/65/15 I’m sure they’ll work, but is there a basic on-line calculator where i can plug this in and get the total diameter… Tire rack says just take the aspect ration and mulitply by two then add the wheel diameter… i dont buy that. ---
**Author:** ![NVmySX](https://avatars.discourse-cdn.com/v4/letter/n/f07891/32.png) [@NVmySX](https://forums.speedlife.net/u/NVmySX)\ **Post date:** [December 1, 2008, 3:27pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/2 "2008-12-01T15:27:45Z")
heyy bing maybe this will help? [http://www.americastire.com/dtcs/infoTireMath.dos](http://www.americastire.com/dtcs/infoTireMath.dos) ---
**Author:** ![Theo23](https://avatars.discourse-cdn.com/v4/letter/t/43a26b/32.png) [@Theo23](https://forums.speedlife.net/u/Theo23)\ **Post date:** [December 1, 2008, 3:29pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/3 "2008-12-01T15:29:39Z")
[http://www.discounttiredirect.com/direct/brochure/info/tmpInfoTireMath.jsp](http://www.discounttiredirect.com/direct/brochure/info/tmpInfoTireMath.jsp) For those sizes, it says: If your speed reads 65 miles/hr, you will in fact be going 64.5 miles/hr. So yeah, not much of a difference at all. ---
**Author:** ![kimmerkaze](https://avatars.discourse-cdn.com/v4/letter/k/9d8465/32.png) [@kimmerkaze](https://forums.speedlife.net/u/kimmerkaze)\ **Post date:** [December 1, 2008, 6:29pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/4 "2008-12-01T18:29:57Z")
^^your overall diameter will also be affected if the 16’s and 15’s are not the same width from the stretch but pretty minimal since i guess they’d be like 0.5 or an inch off if they were different. ---
**Author:** ![sidewayz240](https://avatars.discourse-cdn.com/v4/letter/s/e99b99/32.png) [@sidewayz240](https://forums.speedlife.net/u/sidewayz240)\ **Post date:** [December 1, 2008, 6:47pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/5 "2008-12-01T18:47:26Z")
convert width of the tire to inches, take the sidewall percentage of that, muliply by 2, add wheel diameter Ex. 205mm = 8.071" 8.071 x 0.60 = 4.84 4.84 x 2 = 9.68 9.68 + 16 = 25.68" overall diameter ---
**Author:** ![bing](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/bing/32/7211_2.png) [@bing](https://forums.speedlife.net/u/bing)\ **Post date:** [December 19, 2008, 1:05pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/6 "2008-12-19T13:05:06Z")
> [@mazda speed 3](https://forums.speedlife.net/t/mazda-speed-3/19218/50): > > [Discount Tire Direct now partners with Tire Rack](http://www.discounttiredirect.com/direct/brochure/info/tmpInfoTireMath.jsp) > > For those sizes, it says: > > If your speed reads 65 miles/hr, you will in fact be going 64.5 miles/hr. > > So yeah, not much of a difference at all. FYI, that calculator is awesome… exactly what i needed and i’ve used it a dozen times since… good link. ---
**Author:** ![logik23](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/logik23/32/5548_2.png) [@logik23](https://forums.speedlife.net/u/logik23)\ **Post date:** [December 19, 2008, 1:53pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/7 "2008-12-19T13:53:34Z")
You can easily do it yourself like sidewayz did. ---
**Author:** ![bing](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/bing/32/7211_2.png) [@bing](https://forums.speedlife.net/u/bing)\ **Post date:** [December 19, 2008, 1:58pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/8 "2008-12-19T13:58:02Z")
running the numbers through that calculator is faster… especially when you’re contemplating multiple tires sizes ---
**Author:** ![Theo23](https://avatars.discourse-cdn.com/v4/letter/t/43a26b/32.png) [@Theo23](https://forums.speedlife.net/u/Theo23)\ **Post date:** [December 19, 2008, 4:23pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/9 "2008-12-19T16:23:18Z")
> [@Thoughts on winter car...](https://forums.speedlife.net/t/thoughts-on-winter-car/19603/13): > > especially when you’re contemplating multiple tires sizes Yeah, it’s great for that eh. I’m glad you found it usefull Bing. ---
**Author:** ![sr20](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/sr20/32/5491_2.png) [@sr20](https://forums.speedlife.net/u/sr20)\ **Post date:** [December 19, 2008, 6:09pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/10 "2008-12-19T18:09:15Z")
this is what i use\>\> [http://www.miata.net/garage/tirecalcold.html](http://www.miata.net/garage/tirecalcold.html) ---
**Author:** ![bing](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/bing/32/7211_2.png) [@bing](https://forums.speedlife.net/u/bing)\ **Post date:** [December 29, 2008, 10:48am UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/11 "2008-12-29T10:48:34Z")
anyone have a link to one of those charts that shows what tire sizes you should put on rim widths nad vice versa? ---
**Author:** ![rogerthat240](https://avatars.discourse-cdn.com/v4/letter/r/839c29/32.png) [@rogerthat240](https://forums.speedlife.net/u/rogerthat240)\ **Post date:** [December 29, 2008, 11:52am UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/12 "2008-12-29T11:52:59Z")
[http://www.1000rims.com/rt\_specs.jsp](http://www.1000rims.com/rt_specs.jsp) my favourite ---
**Author:** ![sil8t](https://avatars.discourse-cdn.com/v4/letter/s/ea666f/32.png) [@sil8t](https://forums.speedlife.net/u/sil8t)\ **Post date:** [December 29, 2008, 12:26pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/13 "2008-12-29T12:26:24Z")
^^^it wont let me strech tires what the funk ---
**Author:** ![polishprince](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/polishprince/32/5690_2.png) [@polishprince](https://forums.speedlife.net/u/polishprince)\ **Post date:** [December 29, 2008, 12:27pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/14 "2008-12-29T12:27:23Z")
> [@Happy Birth NotJustATrophyBitch](https://forums.speedlife.net/t/happy-birth-notjustatrophybitch/19594/14): > > this is what i use\>\> > > [Tire size calculator](http://www.miata.net/garage/tirecalcold.html) this is the one right here ---
**Author:** ![bing](https://yyz2.discourse-cdn.com/flex034/user_avatar/forums.speedlife.net/bing/32/7211_2.png) [@bing](https://forums.speedlife.net/u/bing)\ **Post date:** [February 14, 2009, 5:54pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/15 "2009-02-14T17:54:46Z")
how about one of those charts that tell you what min / max tire size by wheel width?? ---
**Author:** ![s\_14\_2nv](https://avatars.discourse-cdn.com/v4/letter/s/5e9695/32.png) [@s\_14\_2nv](https://forums.speedlife.net/u/s_14_2nv)\ **Post date:** [February 16, 2009, 12:47pm UTC](https://forums.speedlife.net/t/tire-size-calculators/120260/16 "2009-02-16T12:47:54Z")
Bing try this [http://www.rims-n-tires.com/rt\_specs.jsp](http://www.rims-n-tires.com/rt_specs.jsp)