I just bought a used set of Challenger Rollers and when I use the fork stand I get a loud noise from the front roller. The noise becomes louder the harder I pedal and sounds rather "clunky". Is this noise typical?

I assume not because of all the great things I have heard about these rollers. The set is only seven years old and experienced moderate use for three of the seven years. Is it time to have the bearings inspected? Has anyone ever sent a roller to Kreitler...is it crazy expensive?

Does anyone service Kreitler rollers aside from the manufacturer?

Thanks for the help.