but what does the number of ply's reference? I
thought it was just some extra layers of rubber (presumably because
they're
holding more weight?)

Exactly.

Why would having
a lower ply count rub on the brakes while a higher number does not?

Ours didn't rub, they were just too light of tires for the job. The POH
calls for 8 plys.


What
year Aztec do/did you own Jim? I thought Kyler Laird was the only other
Aztec owner that regularly posts on the group.

1966 C model non turbo
We bought it in August.

Jim


---
Outgoing mail is certified Virus Free.
Checked by AVG anti-virus system (http://www.grisoft.com).
Version: 6.0.782 / Virus Database: 528 - Release Date: 10/22/2004