Originally Posted by
superdex
Don't sand.
Get out your spoke wrench and tighten everything 2 turns. Poof, you've shrunk your radius. You're welcome.
To do this by spoke tension only one has to compress the rim to a smaller circumference. The materials that rims are made of are VERY reluctant to compress without serious forces, think the efforts to forge crank arms as example. Spokes and nipples will fail long before this lever of force can be applied. What will happen is that the spokes will stretch, localized deformation will happen at the spoke holes in the rims (and pull through or crack in time) and maybe the hub flange will fracture.
Of course since I am sometimes clueless about forum posting indications of sarcasm superdex might be trying to make a "joke". Too bad it's advise can lead to more damage then benefit. But if the OP did follow this bad advise and did ruin their rim/wheel and had to replace them/it the new wheel/rim might turn out to be easier to mount a tire to
Andy