[TowerTalk] US TOWER HDX-89 / Tash DX86 Wind Rating Differences

[Richard Thorne]

This may not be comparing apples to apples but here's my question after 
studying the two towers.

US Tower HDX-89 claims 9.2 sq ft of max allowable antenna wind area 90 
mph 3 second gust
Tash DX86  claims 21 sq ft of max allowable antenna wind area 85 mph 3 
sec gust

After looking at both designs they both start with a lower section that 
is 28.75" wide and a top section that is 13 7/8" (Tash) and 13 15/16" 
(US Tower)

So the designs appear to be the same, why are the allow able antenna 
wind loads so different?  I realize that one is based on 90 mph the 
other on 85 mph.  Does the 5 mph delta add up to a 11.8 sq ft difference?

Thanks in advance.

Rich - N5ZC