Send in your old drum, get it back with an unobstructed diamond cutting surface, not plated CBN (cubic boron nitride)*.
$99 gets the job done with free return shipping.
Your drum is stripped of its existing abrasive to bare metal, machined round, primed, machined round again, bonded with diamond abrasive, and oven cured.
Expect tires to cut more evenly with less increase in temperature grinding with the hardest material on earth.
*Other vendors are selling plated CBN (cubic boron nitride) as "diamond.".
International shipping also available at discounted rates.