ORIGINAL: FROGGY-RCU
before glueing your wheels and tires clean them with denatured alcohol.the wheels and tires have a releasing agent on them so they will come out of the mold and glue doesn't like sticking to it.
Great suggestion - but so far here in the UK where he is, I can not find denatured alcohol myself.
I know tha sanding does help. wipe away any loose particles with some cleaner of some kind. They should not come unglued that easily.