I had to have some wheels freighted down from Sydney to Melbourne recently - this is the company I used: http://www.airroaddirect.com.au/airroad/home.sok

4 wheels and tyres cost me approx. $115 - each wheel & tyre weighed about 20kgs, however I was able to have them 2 in a box. Max weight for one item was 50kgs I think.

They were packaged in cardboard boxes bought from pack and send. Picked up in Sydney and delivered next day to Melbourne.

I would recommend them.

Yep 2 in a box should be fine - delivery to Tassie may be more expensive than Sydney to Melbourne because it requires crossing bass strait ie. boat journey.

Also remember that the size of the item also determines the price - it has a 'cubic weight'. The bigger the box, the more 'weight' it can hold - don't have 2 big a box as you will be paying for air! While my wheels weighed no more than 45kgs a box - for the size of the boxes they were in I was paying for 105kgs of weight. if you know what I mean lol...

I've used airroaddirect also.

Do a good service for wheels, door to door offering $1000 free transit insurance.   The tracking can also be useful to know the wheels are on the track, at the depot etc. You used to be able to get away with taping cardboard to the surface but they want at least the entire wheel to be bubble wrapped now.  You can get a decent roll of bubble wrap from Packsend www.packsend.com.au - they sell it by the metre and it is wide so wraps around the wheel nicely.

Make sure you leave adequate instructions for pickup or delivery in case either party is not home at the time of drop off/pickup otherwise they charge you extras.

Their pricing is very competitive for wheels but not so good for large items such as seats