i have had a pneumatic tyre fitted to my caravan instead of the normal hard type wheel.i found, as has been said,the hard type tended to twist and dig in to soft sufaces,which prevented it at times from rotating as it moved,hence excess pressure put on jockey assembly.this has been working brilliantly and have had no problems at all,if you do get a mover,and beleive me they are worth the expense,fit a pneumatic tyre.