Tire Size Calculator

[G8H8]

Don't know if this has been posted before but I have had this site saved on my computer for years

http://www.miata.net/garage/tirecalc.html

[GRRRR8]

Thank You!

[BlueJacket]

I think everyone uses that calculator. Its the only good one I ever see anyone post.

[-Ray-]

I believe thats the best one out there.

[Joe Weinstein]

Hi all. Online tire calculators are well-meaning, and will usually get
you a decent ballpark estimate, but if you're dealing with tight
fits or matching diameter issues, like I have with my AWD car that
has different width tires in the front and back, these calculators
can be very far from reality precisely when it matters most.
Here is a post I made to another forum:

Hi folks. danger danger. ... Never, never use any online generic
'tire size calculator' if you are dealing with close tolerances, such
as trying to prevent rubbing or if you need identical front and rear
diameters like we do. They all mean well, and are simply designed
according to what the tire size nomenclature is *supposed* to
mean, but in the real world there is a wide range of variance
between what a tire is designated as and what it's real dimensions
are. For the real facts you have to go to the tire manufacturer's
model-specific spec sheet. I have seen two different 245/45-16 tires
differ in diameter by 1/2 inch *from the same manufacturer*!
They were just different model tires. Recently one tire manufacturer
stopped making it's 305/30-18. Now they list a 315/30-18. *It's the
same tire*! They just decided that the actual tire dimensions were
closer to the 315 meaning, so after 6 years they just changed what was
printed on the sidewall.

To let you know how poor a ballpark answer they provide. Go to
tirerack.com and look at the spec sheets for 225-40-18 tires, and
you will find that their actual diameters vary between 24.8" and 25.5".
The latter value is taller than the average 235-40-18!

225-40-18 tires:

Hoosier A6 - 24.8"
Bridgestone expedia S-01 - 24.9"
...
Michelin Pilot Sport - 25.3"
Dunlop Sp Sport 01 - 25.5"

Now look at the supposedly larger 235-40-18 tires, eg:

Dunlop Direzza Z1 - 25.1"

I'm saying that however helpful these generic formulas are trying
to be, they are quite easily capable of being way wrong, precisely
when it matters the most to be right.
Joe

[p71]

This (http://www.1000rims.com/rt_specs.jsp) is way better than the miata one.

[G8H8]

This (http://www.1000rims.com/rt_specs.jsp) is way better than the miata one.

HTTP Status 404 - /rt_specs.jsp

type Status report

message /rt_specs.jsp

description The requested resource (/rt_specs.jsp) is not available.
Apache Tomcat/5.5.26

[nph2005]

This (http://www.1000rims.com/rt_specs.jsp) is way better than the miata one.

:thumbsup: I have been using that one for years. Much better than the miata one.

http://www.rimsntires.com/specs.jsp

[Slizzo]

:thumbsup: I have been using that one for years. Much better than the miata one.

http://www.rimsntires.com/specs.jsp

Yeah, this is the one that I like. Much easier to use and get useful information from.