A lot of people think that one reading gives you accuracy and they give up because their readingas are all over the map. I mentioned it earlier and this is directly from from PTC's FAQ at http://www.ptc1.com/durometers_info.htm
"How do I use a durometer ?
In use, a durometer is pushed against the sample and the hardness is read from the dial. It is a good practice to take several readings and average the results."
Personally, I take a bunch of readings in different locations on the tire and keep a running tally of the average.
Another thing touched on here is a term I coined years ago I call "bounce". Basically when you true your tires tighter to the rim they have less bounce and therefore, a durometer reading is going to be higher [read
ff] and you have to figure this in. There is not a good concrete way to do this and much like taking durometer readings without a stand... it's all feel.
The _only_ way to get dead nuts measurements with a durometer is on a stand, on the same diameter foam from the wheel, and nowhere near a glue seam. Unfortunately, we do none of that. HAHAHA