Dynamically Responsive String-bed
Power, Control, and Comfort
The current conventional racquet design approach asks the frame to perform inherently opposed functions, control, comfort and power, at the same time. It can't. It's a simple reality of physics and it's the root of the embedded power-control compromise in the selection of a racquet.
In the face of today's increasingly powerful game, the current model is broken. A conventional frame can only be made so flexible/comfortable before it loses its capacity to maintain directional control of the ball, and it can only be made so stiff and powerful before it's too uncomfortable to play with, particularly with stiff strings. We're there, we have reached the limits of the engineering model.
In applying the engineering model of suspension to racquets, and utilizing the latest in high-tech materials and manufacturing techniques, BOLT has moved past the conventional design paradigm and raised the bar for racquet performance to an extraordinary new level.
Suspension opens a door to nearly limitless development potential of racquets into the future. As a means of controlling ball-rebound speed, it's certain to be an integral component in the future of racquet performance. BOLT has pioneered its development and is committed to advancing racquet performance for today and for future generations of players.
Instead of the frame flexing to control ball-rebound speed, the ZIPSTRIP flexes, while the frame remains quiet, stable, accurate and powerful.
1. Ball impact on a flexible frame: ball energy is absorbed as the frame deforms - red arrow
2. Ball rebound: if a ball releases too late from the deforming frame it can be substantially off its "true" flight line
2A: Ball rebound: if a ball releases from the deforming frame too early it can be substantially off its "true" flight line
3. Ball impact: a flexible frame deforms in all directions further eroding accuracy and dulling the sharpness of the string-bed response
Current Racquet Dynamics
The performance of every conventional racquet has a built-in compromise:
'More power, less control.
More control, less power.'
This embedded compromise is the result of a broken engineering paradigm. In the context of modern materials and manufacturing techniques, racquets can now be designed to far higher standards of performance. Players can and should expect more from their racquets.
Conventional racquets today still rely on a century-old design paradigm. These old-school racquet dynamics, illustrated here, are left over from the days of wood and metal racquets. Currently, this old-school dynamic is applied to high-tech composites. In order to absorb ball impact energy and control ball rebound speed, high-tech composite racquets are made to flex and bend like wood. While ball rebound speed is controlled, and a degree of comfort can be achieved, a frame is less accurate and less powerful as it becomes more flexible - this is the built-in compromise.
1. Ball impact: stiff frame
2. Ball rebound: a stiff frame doesn't absorb energy and doesn't deform resulting in the "true" flight path
2A. Ball rebound: flexible frame combined with a suspension minimizes deviation from the "true" flight path
3. Ball impact/rebound: energy is absorbed by the suspension system - red arrows - to control ball rebound speed.
Modern Racquet Dynamics
Conventional racquet dynamics simply do not allow for power, control and comfort to each be optimized on the same racquet. It's a reality of physics that one component (the frame) cannot perform inherently opposite tasks at the same time. In order to have control, comfort and power optimized and together in harmony on a racquet, there must be at least one component to handle power, and at least a second component to handle control and comfort.
BOLT has embraced the suspension model for racquets which introduces a second component into the performance equation. By shifting control of ball rebound speed away from the frame and into a secondary component, a patented spring suspension design called a ZIPSTRIP, BOLT has revolutionized racquet performance.
The ZIPSTRIP is a flexible string support that absorbs ball impact energy. Instead of the entire frame flexing to absorb ball impact energy, the ZIPSTRIP flexes. It enables every BOLT racquet frame to be solid and stable - designed for precision, accuracy, control, and comfort - at any level of power.
The BOLT is a dynamically responsive instrument, not just a stick with strings.
ZIPSTRIP spring suspension is the core engineering innovation of a BOLT racquet. ZIPSTRIPs cooperate dynamically with the string-bed at ball impact to improve every aspect of racquet performance.
Power - Control
BOLT is power and control together
Impact shock and vibration nearly zero
Consistently solid feel at contact
Increased string longevity
Accuracy - Precision
Superior Frame Stability
Enhanced dwell time
Spring-suspension has significant implications for both the size of the sweet spot and its location on the string-bed.
Deflection of the string-bed on a BOLT is a function of both the elasticity of the string and the elasticity-flexibility of the ZIPSTRIP. In its Compression stage, the ZIPSTRIP effectively elongates the length of the strings and deepens the "pocket" significantly - this is the key to the extraordinarily forgiving response of a BOLT. Even balls contacted well away from the center of the string-bed can feel like solid hits with some speed on the rebound.
In the Spring-back stage, the string and the ZIPSTRIP return to their static positions while imparting their stored energy into the ball release. It cannot be overstated how critical this small half-second window of ball impact and release is to the overall feel and performance of a racquet. The ZIPSTRIP works in that window and more importantly, it provides control of the impact-release reaction.
In a conventional racquet, the strings are connected directly to the frame - fixed and rigid. In this case, deflection of the string-bed depends solely on the string - length, type, and tension. The relationship of string to frame is static and unforgiving and it's the reason why balls contacted near the edge of the string-bed feel "dead" - the string is unable to flex in any other direction but perpendicular to the string-bed surface.
Largest Sweet Zone - Optimum Location
Not only is the sweet spot of a BOLT much larger than a conventional racquet but it also expands to become even larger at ball impact - this is the dynamic, forgiving response of the suspension. More importantly, the BOLT Dynamic Sweet Zone expands towards each ZIPSTRIP, making it possible to control its location on the string-bed.
With the ZIPSTRIPs located at 3, 9, 12 o'clock as shown here, the Sweet Zone covers a majority of the upper portion of the string-bed and the unique, slightly elongated head shape of a BOLT purposely accentuates the effect. Certainly a strip can be located at 6 o'clock for example, and the Sweet Zone would expand accordingly but to expand the Zone toward the handle may not be beneficial for every player. The particulars of strip locations, strip type, etc. will be based on the target frame specifications and intended player profile.
As research strongly demonstrates, the "high sweet spot" of a BOLT as shown coincides with typical ball impact location of nearly all advanced players and a majority of players generally. It's unique among racquets today and it's available only on a BOLT.
Stable Frame - Flexible Suspension
In the suspension model the frame is not the element responsible for control and comfort, the suspension does that. The objective of BOLT racquet frame design then is not a search for degrees of flexibility, but a search for maximum strength, stability, and lightness. Degrees of flexibility can be pursued in the suspension system. Strengthening the frame construction will open up further possibilities for activating the string-bed.
Impact forces isolated - impact forces are localized and absorbed directly by the ZIPSTRIPs right at the string-bed. Impact shock, vibration, torque, and other unwanted impact "noise" are minimized before reaching the frame itself. This is key to the unprecedented "smooth ride" of the BOLT. It's also the key to a BOLTs' reduction of impact "pop" to nearly zero. Impact pop is the critical factor in arm-related injuries and the ZIPSTRIP minimizes it to a degree that puts it in a league by itself. It's a perfect compliment/solution to the stiffness of polyester strings.
Impact forces direct to frame - impact forces are transmitted directly from the string-bed to the frame. The entire frame is subject to unwanted vibration, rattling, torque and a host of other unpleasant feedback which subsequently translate to the handle. Handle vibration dampening systems merely compensate for a portion of frame vibration and they have no impact overall on the unwanted racking, twisting, and bending of the frame itself.