I was checking on those American Racer tires mentioned in another thread and the guy I spoke with said he did not know how their 'SD23' compound compared to the Hoosier A6 or Hankook C71 compounds.
did say they have a durometer reading of, get this, 26. Damn that sounds soft. From what I see on the internets (which of course are never wrong!) A6's are about 50 durometer.
Anyone have durometer readings for the A6/C71 or anything else, for comparison purposes?
I don't know.....the googles just told me, though, that all readings are +/- 5 points. It would be good to keep that in mind if we get some readings that are close.....
http://www.rubbermill.com/PDFs/tech/durometer.pdf
Interesting. The 26 durometer he mentioned is super soft, according to that chart.
Take a look at these measurements, too
http://en.wikipedia.org/wiki/Shore_durometer
Could this also be related to which scale is being used? "Shore A" vs "Shore D" or whatever they are?
Sorry, just enough durometer knowledge to add uncertainty...
The testing method is different, so there's no direct mapping from one reading to the other, but it does look conceivable that a tire could be close to 50 on one scale and 26 on the other? (EDIT: e.g. it could be 50 shore A and 26 shore D without being a big outlier in this chart) (This table covers stuff decidedly different from tires, and is only intended to illustrate that there's overlap...)
From a link listed in a discussion at http://www.eng-tips.com/viewthread.cfm?qid=245132
Why do we need multiple durometer scales? They might as well measure tire hardness in "aardvarks per cubic furlong" or some other arbitrary and silly unit.
According to the Wiki and everything else I've seen, the Shore A scale is generally used for tires. All the tire durometers I looked at online say 'Scale A' on them somewhere. Like this Intercomp:
So I am assuming the 26 figure he quoted is on the shore A which makes it a real soft tire. That's why I'm hoping someone on here has a set of A6's or etc that they can check the durometer on, that will give a rough frame of reference.
The Shore D is used for harder stuff, the O and OO etc are for real soft stuff like sponge rubber.
OBTW: if these tires work out, the pricing is FANTASTIC. 
Shore D scale starts harder than A leaves off.
A hard skateboard park wheel is high 90s Shore A - most polyurethane car bushings are in the 80s.
Stuff that's on the D scale doesn't feel like an elastomer to the bare hand.
for comparison, a Blizzak measures 45.
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