[AT] OT truck tires/driveshaft?

[jtchall at nc.rr.com]

Dropped the air pressure in the front tires to 65 and the vibration dropped 
to tolerable levels, at times not even noticeable. I had close to 80 in the 
tires, I'm thinking the tires call for 85 or 90 psi. The guy that sold me 
those tires says 65 should be fine. I don't understand the discrepancy 
between what he is telling me and what is listed on the tire.
Could vibration with higher pressure be a sign of bad shocks (I guess it has 
them on the front, haven't looked). Anyway, got a small load of scrap iron I 
need to haul. Not enough weight to load the truck but I should be able to 
get an idea if the vibration is going to be tolerable.

John