Drum struggling to turn?

Hi..... Tumble dryer stopped working as belt became slack and the small wheel that belt goes around shattered. We replaced the wheel and belt put it all back together and now the drum is struggling to go around. If you have nothing in the drum it goes round slightly better than if you do. It is also making a whiring sound when going round. We think everthing has been put back right. We have taken to bit twice and reassembled. Many thanks.