A Century Later, String Suspension Arrives at Last
Is string suspension the "holy grail" of tennis racquet design? Considering the 100 year long history of failed attempts to achieve it in a commercially viable racquet and its potential to transform the foundations of racquet design, it would be hard to argue it isn't. Almost from the beginning, manufacturers have considered various ways to achieve string suspension on a tennis racquet. Some of the earliest patents for improvements to racquets, dating as far back as 1888, include string suspension concepts.
As tennis became popular in the late 1800's, players realized that hitting a ball hundreds of times a day was hard on the body (tennis balls of the era were especially hard so that didn't help!). It was natural that engineers were imagining ways to mitigate ball hitting impact in the racquet and they recognized early on that the most direct and impactful way to address the problem was with string suspension of some kind. Suspension in principle was being explored in the automotive industry at the time as a method of separating wheels from chassis, allowing them to move independently of each other and providing comfort to passengers, so to adapt it for use in a tennis racquet was not a stretch for a creative industrialist. In engineering terms for this discussion, true string suspension on a racquet is the separation of the strings from the frame in such a way that allows the strings to move freely and independently of the frame in response to ball impact.
It should be emphasized that string suspension is not merely separating the strings from the frame. Separation is easy and can provide some degree of vibration dampening. The typical grommet strip of a modern composite racquet is a "separator" of sorts, acting as a gasket between the strings and the frame. The leather pads that Roger Federer has located under the main strings at the throat of his racquet provide separation with a degree of vibration dampening, but to separate the strings from the frame while at the same time allowing them to move freely in response to ball impact offers an entirely new kind of performance. It's the ideal model of string suspension on a tennis racquet. It's also the most difficult to achieve because it requires a sufficiently strong independent support structure for the strings which adds weight, and it's excess weight that makes execution of true string suspension in a commercially viable high-performance racquet, nearly impossible to achieve. Adding even a small amount of extra weight to the head frame is difficult to do without making a racquet unwieldy and difficult to swing.
There are some truly amazing racquet suspension designs in t