The pilot of the tailwheel equipped airplane reported that during the landing roll, and after the tail wheel touched down, the airplane swerved to the right, then to the left, and veered off the runway to the right and impacted an airport sign. The airplane sustained substantial damage to the right aileron. Following a postaccident examination of the right/left main landing gear wheel, the pilot sent an email to the Federal Aviation Administration (FAA) Inspector, regarding the Timken bearing for the main landing gear wheel, this email stated in part: "The bearing itself is a stock Timken 18200 bearing, nothing special. While jacked up the wheel turns fine by hand. And this is unlike any failed bearing I've seen. And getting close to a CND (cannot duplicate) condition. I think it is possible the bearing was in the process of failing. At touchdown speeds (approximately 60-80 knots) with little weight on wheels the bearing could lock up or freeze momentarily causing the aircraft to veer right". A photo of the Timken 18200 tapered roller bearing was sent to the manufacturer for further examination. The manufacturer examined the photo and concluded that there was no evidence of damage or scoring, and further reported that if the bearing would have seized, he would have expected to see damage to the rolling contact surfaces.