Replace rear tire with new
take two old bearings from the rear rim ort buy new bearings remove the rubber seals with a little scribe/small screw driver and clean the grease out so it will roll easy
put on the axle place on two jack stands .
the heaviest part will rotate to the bottom. so add the weights to the top side. on mine i put 3 weights in the thread groves and it seemed close so i glued two on the rim then added one more for perfect. i used black silicone i hope they don't come loose at 100 lol
i am going to try and put a couple of pictures on by phone