Rpm Knuckles Question?

[Mike_D]

I was wondering does anyone here use the rpm knuckles on there maxxes? The reason why i am asking is because i have been using these for about a year now and it seems like there is a lot of slop where the bearings are and it does seem to be getting worse. I did replace the bearings just recently thinking that they were bad and that did not seem to help. Is this a common problem and would upgrading to aluminum help this at all? Thans guys for any and all help.