Golf Ball Performance
Launch Conditions - describe exactly what the golf ball is doing immediately after impact. The most critical launch conditions affecting performance are golf ball speed launch angle, backspin and sidespin. Golf ball speed is the most important factor in determining distance. Higher ball speed directly relates to increased distance. All shots have backspin. Backspin is certainly helpful around the green for added control, but too much spin can reduce distance.
Aerodynamics - During flight, the launch conditions of the golf ball interact with the aerodynamics of flight to determine the golf balls overall trajectory. The two primary aspects of aerodynamics are lift and drag. Lift is the force that acts in the vertical plane and drag is the force that opposes the golf ball’s motion. Unlike drag, lift needs to be optimised in order to produce the desired trajectory. Too much or too little lift can lead to a loss in distance.
Feel - is a subjective but critical aspect of golf ball performance and a leading factor in golf ball selection. The entire golf ball contributes to feel. The cover is more influential on putts and shorter shots and the core is more prominent in woods and long-iron impacts.
Golf Ball Performance - can be broken down into 4 primary categories:
launch conditions, aerodynamics, durability and feel. Feel and
durability goals are fairly straightforward: the golf ball should feel
soft and responsive yet remain durable and tough. Launch conditions and
aerodynamic performance are more complex - the properly engineered golf
ball must spin, pierce, climb, cut fade, draw or sit differently
depending on the club or shot.
Golf Ball Core
The Core - of every solid golf ball is made from polybutadiene (synthetic rubber) - a highly responsive material that returns most of the energy put into it. Size and stiffness are the primary factors that determine the core’s influence on performance. Polybutadiene can be manufactured to a desired stiffness and the core itself can be designed to different dimensions depending on performance goals.
Core Performance - The core will affect performance for every club in the bag, but it’s especially important for higher swing-speed clubs such as woods and long irons. The polybutadiene rubber core used in golf balls is extremely responsive and is very good at returning the energy put into it. The stiffness of the core can play a role in all launch conditions including golf ball speed, launch angle, backspin and sidespin. Core size also has a large influence on launch conditions, especially golf ball speed.
Core Stiffness - The core is the largest component of the golf ball. The stiffness of the core plays a large role in how the golf ball performs and defines a large portion of how firm or soft the golf ball feels when struck. Golf balls with a stiffer core will generally produce more golf ball speed than golf balls with a softer core, regardless of swing speed. Golf balls with softer cores will compress more against the clubface producing less spin than golf balls with firmer cores. Technologies such as Srixon’s Energy Gradient Growth® are able to vary core stiffness to maximise golf ball speed while keeping driver spin low.
Core Size - Though the core is always the largest component of the golf ball, different golf balls in the market can vary widely in core size. The core can be thought of as the engine of the golf ball. Larger cores are equivalent to bigger engines. Bigger engines mean more power and more power means more golf ball speed. With golf rules restrictions on golf ball size, making a larger core requires producing a thinner cover. Leading manufacturers are able to produce these thinner covers required to achieve maximum golf ball speed.
Golf Ball Cover
The Cover - design plays a large role in overall golf ball performance especially for higher-lofted clubs and shots hit around the green. Depending on its thickness and stiffness (“firm” or “soft” is typically used to describe cover stiffness) the cover has a variety of effects on both golf ball speed and spin. The cover also plays a critical role in durability and feel. There really isn’t a performance aspect of the golf ball that isn’t somehow influenced by the cover design.
Cover Materials - Golf ball covers are made from one of two possible material classes: urethanes and ionomers. Urethane is a very soft strong elastic material and is found on premium, tour-calibre golf balls. Ionomer is a firm plastic that is used on distance focused golf balls found in the market. Urethane and ionomer materials can be engineered to have many different properties - the most important of which are high durability and low stiffness.
Cover Thickness - Golf ball speed and backspin are inversely related when it comes to cover thickness. Thick covers produce less ball speed but more backspin and thin covers have more ball speed but less spin. Since the cover is a lower “C.O.R.” material than the core, golf balls with thick covers also typically have lower ball speed. Greenside spin is generated by maximising the contact surface area between the golf ball and the clubface. Thick covers can deform more at impact and therefore contact more of the clubface so more spin is generated with golf balls that have thick covers.
Cover stiffness - comes with the same trade-off as cover thickness: you can get more greenside spin with a soft cover but that gain in spin will cost you ball speed. The trade-off between backspin and ball speed is not equal. Cover stiffness changes backspin a lot relative to its effect on ball speed, while cover thickness has more of an effect on ball speed. For this reason engineers are constantly searching for ways of making the cover thinner (maximise ball speed) and softer (maximise greenside spin) without hurting durability.
Golf Ball Materials
Golf Ball Materials - there are many materials used in golf balls but the majority can be broken down into 3 categories: rubbers, ionomers and urethanes. In the past, golf balls have been made of wood, leather wrapped around feathers, sap from a gutta tree and sap from balata trees. Over time these materials were replaced by the superior materials used today.
Urethane - is a polymer that is similar to many everyday plastics. Like plastics, many properties of urethane such as toughness and hardness can be controlled. There are 2 types of urethane covers: thermoplastic and thermoset. Thermoplastics are urethanes that get soft when heated up. Thermosets use heat to cure/harden the material. Because they can be reheated and re-moulded, thermoplastic urethanes allow for more precision and design flexibility. Golf ball manufacturers employ chemical engineers to design better urethane compounds. Srixon has proprietary chemicals and processes that can make the urethane softer for more spin without sacrificing durability.
Ionomer - materials are very similar to plastics and are used for mid layers in premium golf balls and as a cover material for most 2 piece golf balls. Unlike urethanes, ionomers do not maintain their strength as they are engineered softer. Srixon engineers are leading the way in developing new ionomers that can stay strong while being made softer. Surlyn® is a particular kind of ionomer and is one of the most common ionomers used in golf ball covers.
Polybutediene Rubber - is a synthetic rubber used to construct the core of every golf ball on the market. One of the polybutediene’s first uses was on auto tyres, explaining why some golf ball manufacturers originated as tyre manufacturers. The most useful property of rubber is its responsiveness. Due to this property the golf ball’s rubber core is where most of the ball speed comes from. Rubbers are not all created equal. The core of the golf ball can be made to be firm, soft or some combination of the two.