Chris,
Spin balancing is always better than bubble balancing. Although it's nice to
have the wheel balanced ON the trailer so that the drum imbalance is corrected
too, I'm not sure that it's really necessary. Reason is that drums are usually
balanced at time of manufacture, and a slight imbalance on the drum isn't
harmful anyway because the drum is small in diameter, relatively speaking.

Dunno about modern tires, but 'in the old days', it was deemed to be a waste of
money to balance brand-new tires. The out-of-balance point would shift during
the first 500 miles or so, causing a perfectly-balanced tire to need
rebalancing. Point is, it probably wouldn't hurt to have your tires rebalanced
after the first few hundred miles.

If you do decide to get the tire balanced while mounted on the trailer (if you
can find someone to do so!), be sure to mark the wheel and drum so it can be
reassembled correctly after you do your annual bearing maintenance. The wheel
must go onto the same spindle it came off of, and it must be located properly
on that spindle/drum.
 

Chris Elliot wrote:

> Along this same topic..
> An a/s dealer,vintage parts supplier,told me that when installing new
> tires,one should balance the entire wheel with the brake drum attached,as
> trailers are very sensitve to tire balance.Not having started brake rehab
> yet,I dunno whats in there,but having removed drums this way on old cars,I
> can visualize process.
> But if anyone has done it,I would appreciate walking me thru it,verbally.
> Most important,Is it neccesary,and spin or bubble balance?
> Chris Elliott
> ^& Caravel
> &! safari