Steelie Resolve Reveals a Hidden Truth: Tire sizes, and buying used rubber.

For those of you who might not be on Pheobe’s Facebook page to see what all goes on with her, I figured I’d let you know about the little discovery I made this week when getting back to my steelies from the Miata wheels.  This may be a lesson to pay better attention if you’re trying to save a buck by buying or trading used tires, as I asked for a full set of 185/60/14 sized tires for barter of the same size snow tire.

Here are some reference points for those who don’t know the technical points of tire size:

See this chunky, Miata-wheel mounted rubber?

Well these tires are apparently 195/60-14’s and not the 185/60-14’s I’ve been running for years– the latter already adding a chunky look against the factory 175/65-14 look.

Look like gibberish code?  Here’s how to decipher it, albeit backward:
-14 is just the wheel (metal bit) diameter in inches.
-60 is a percentage of the width of the tire (what we look at next).  This is usually called “aspect ratio.”  A common reference you hear today might be “low profile tires,” which are when there’s a massive wheel and very little rubber seen from the side of the car.  Well that is a small aspect ratio.  If you look at the photo below, the sidewall (basically from the ground to the bottom of the rim– the tire thickness) is 60% of how wide that tire is.  Both tires below are a 60% ratio, but the front tires are wider than the rear by 10mm.

-195 means the tires are 195mm wide where they meet the road.  The difference between the right and left tires below is 10mm.

Go look at a ruler and laugh at 10mm all you want, but when you compare a 195 to a 185 (albeit the Miata wheels are 6″ wide while the steel wheels are 5.5″) you see it’s not such a bad change on an Echo.

And what of that wheel width making a difference in tire stance?  Well, the side-walls are going to be more flush with the lip, of course.  As it turns out, the Miata wheels were 195/60’s on two wheels, and the other pair were 185/60’s.

Looking at the back here, you’re looking at a 185/60-14 on a steel wheel versus Miata wheel.  Still a difference with identical tire sizes.  Also note my new red Eibach springs perched in back.

I know she doesn’t sit super low on the steelies, but this is still a considerable drop of around 2″.



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