Most vibrations are due to tire wear. If your tires are not rotated on a regular basis (every other oil change,assuming that you due an oil change every 3,000 miles) you will most likely have minor or severe tire vibration. Vibrations will also be felt depending on tire style as well. For example, an all terain tire will be a smoother less vibrating tire than a mud terrain tire. Also Be sure to check for suspension problems (loose tie rods, out of round tires, out of balance tires, etc) Most likely it is a very simple solution. Typically Suspension components cause vibrations at all rates of speed.