We experienced a pretty good elevator vibration in an Excel (XLS actually). We were climbing out and while accelerating through about 230 the yokes began vibrating (about half what the stick-shaker would feel like). It smoothed out as we climbed at 250 and we called maintenance. It was not evident during the arrival.

We met the Citation Mobile Service mechanic the next day as he was replacing the four elevator trim attachment bolts (2 bolts per each tab). I was surprised to learn that these bolts are not supported by bearings or even bushings. He checked cable routing and tensions, but these bolts were noticably worn. He told us that this was fairly common after about 2,000 hours. The test flight was uneventful.

Based on the mecanics awareness of this issue and his confidence in the fix I believe this is what happened.