[chrisguyw]

And just another observation...

It appears that I will only use about a quarter of the drum width to true my 1/32 rubber tyres. Is there a way to use the full width of the sanding surface over time to get full value out of the drum?

Hi Jeremy, ...you can move the the axle a bit laterally by loosening the grub screw on the axle pulley, and moving the axle a touch...............this will give a bit of movement, but, not enough to allow the full use of the width of the drum. 

Remember that these machines were initially used to cut the much wider sponge tires used in 1/24 and RC cars.

I would not concern yourself too much with the wear on the drum................clean it off once in a while with a toothbrush (preferably an old one), and you will have no issues...........I trued hundreds of sets of tyres (rubber/sponge/urethane) for the customers at our commercial track without even thinking of replacing the drum.

Cheers
Chris Walker