Have you ever noticed the weights on the tires on your car? They are there to balance the tires so your car does not vibrate while you are driving. The tires cannot be perfectly made and they need a little help. This is the story of the Englewood engineer who figured out how to do that. His invention changed the world.

The Merrill Wheel-Balancing System was the world’s first electronic dynamic wheel-balancing system. It was invented in 1945 by Marcellus Merrill at the Merrill Engineering Laboratories, 2390 South Tejon Street, Englewood, Colorado, and is now recorded on the list of IEEE Milestones in electronic engineering[1] and as an American Society of Mechanical Engineers landmark.

Before Merrill’s invention, all-wheel-balancing for automobiles, trucks, etc., required removal of the wheel from the vehicle. Most required some form of static balancing without wheel rotation, which was slow and error prone.

Merrill’s invention balanced wheels while still mounted to the vehicle, by spinning them at high speed and electronically analyzing the vibrations to trigger a strobe light. Technicians could then determine where balancing weights should be added.

This system was developed for balancing crankshafts of high-speed racing car engines and later for use by General Electric Company for 2,000 to 3,000 pound rotors.

Elements of Merrill’s dynamic balancing systems are still used today, primarily for industrial and automotive production applications. The Merrill Axle and Wheel Service is still using (as of September 1999) one of the Merrill aligning machines and a Stewart Warner strobe balancer designed on the Merrill system.