I'd assume such road disturbances would be part of the factor of safety that is included in the spec of the tire. IOW, the weight and speed ratings of the tires do not assume billiard table smooth roads - they include reasonable dynamic loads that could be expected in normal use.
But like all factors of safety, there are limits, and if you have the tire loaded to the max, temps at max, speeds at max, etc., eventually you're going to run out of margin. So if you're pushing in one aspect (e.g., weight), you probably want to avoid pushing on another. If I had a rear FJR tire loaded to the max weight on the sidewall, I certainly wouldn't be pushing hard on a bumpy road.
- Mark