2 Dec
2015
2 Dec
'15
8:06 a.m.
On Wed, 2 Dec 2015, Paul Koning wrote:
Actually, it's the circumference that matters, not
the diameter.
I always thought that there was a relatively stable relationship between
those! :-)
Circumference tends to be a little over 3 times the diameter (3.0 in some
states) :-)
Does the circumference of a rubber roll change
significantly when you
press on it?
If it shifts or squeezes out to the sides, not so much.
If it compresses, yes.
Before TPMS, some cars got a crude estimation of low tire pressure by
comparing the RPM of a tire (ABS sensors) with its fully inflated
brethren.
(circumference changing with pressure change)