usually, a bad idler arm will not make a wheel/tire "hop " as you describe, especially if the car is not moving as you stated when the wheels were spun up to 60mph. this is usually caused by a bad wheel, or a bad tire, or a combination of the 2. It is possible that the brake drum is out of balance, causing the problem if this happens when the vehicle is not moving, and the wheel, tire , and drum assembly are spun as one. Have you checked the wheel bearings, and the proper wheel bearing adjustment