[Spridgets] Tire Sizes

[derf]

I ran 175/70s on my 73 RWA Midget.  I like the way they rode and
looked.  But, since you are square, you'll have to stay skinny.
This chart might help

http://www.tirerack.com/tires/tiretech/45_conversionchart.html

According to the chart, your tire is the same as a 165/80 13.
The 165 is the width in mm.  80 is the aspect ratio, in this case the
tire is 80% as tall as it is wide. (60s are 60% as tall, 70s are 70%
as tall, etc)
The 13 is the rim diameter.
The R and S mean something, but I can't remember, maybe R for radial
and S for snow.

So, get the 165/80 13s and zoom zoom along.
Cheers,
Derf