They quote that they have a lifetime warranty so even if they were worn out after a season of use then they would replace free of charge.
i have not tore down my shee yet to fit them but if you were worried they could walk down the arm spindle then you could mod the arms with small grub screws perhaps? from memory i am pretty sure my lonestar arms are machined at the ends so have a step, will take some pictures when i do the job for future reference
I have the parts in my hand and quality looks great, will see how well they stand up compared to the plastic ones which only lasted a year with the quad being used around motocross tracks.