Riding to work today I noticed a bad vibration from my back tire at speeds over 100mph on the interstate. I just did a "short" 100mph run on a pretty much empty roadway at 5am.(I know,... kinda squidly, but couldn't help myself...my Kaw wanted to run.) Is this a balance issue or should I be looking for something else. Its definitely coming from the rear tire(not head-shake). Checked my tire pressures and they're all OK, (factory pressure.) Did a search on this but came up with nothing. Any ideas? Could it be suspension related? I haven't had a chance to change my settings yet and they're all still at stock.