On Sun, 29 Jul 2007 15:39:44 -0700, Chris_MdR wrote:

If they are bias ply.  If they are radials, and they didn't smooth out on
the test drive, plan on changing them. Check the date codes, if they are
over 5 years old, they will need replacing.  If they are bias ply, figure
on changing them anyway.

I see where Chris_MdR@gmx.net contributed:

If the tires are so old they have nylon plies, it's normal but they
need replacing on age alone.  

Will Sill - think about this:
Stupid ideas remain stupid, even when millions of
stupid people are persuaded to accept them.

'Quick question for the RV experts: When an RV has been standing for a
bit, and the tires are not entirely round, i.e. vibrate quite a bit
during the test drive, will they 'even out' with proper air pressure and
a bit of driving, as the seller claims???
Thanks!!
Chris'

REPLY:   Depends on how long its been standing.  Sometimes they will .
If its been standing a very long time in the weather, you need to check
the tires for dryrot too.

The simple answer is absolutely: NOOOooooo!!!

There are certain RVs, built upon chassis' which are infamously
notorious for bad outta-spec-wheel construction, causing irresovable
wheel vibration.