Pin Up vs. Pin Down

What should I do?

“Should I drill this ball pin up to give me some extra length, or pin down to give me an earlier roll?” A vast majority of bowlers today generally make this their primary decision when drilling a new bowling ball. If you’ve ever been in the pro shop business, you’ll hear it all the time.

With so many changes to bowling ball technology over the last 30+ years, what do those changes in layouts really do to ball reaction?

Bowling ball technology has evolved over time making some of our older theories not quite as relevant to today’s game. In order to understand what has changed, let’s take a step back in time and look at bowling ball technology in the early years of bowling.

Past and Present

Early day bowling balls did not have heavy dynamic shapes to create large flare patterns. Take a look at Figure 1. The picture on the left is an example of what the inside of a majority of bowling balls looked like 30+ years ago. They consisted of a small slug at the top of the ball which the fingers and thumb would be drilled over to offset the weight lost from drilling. Since this was the primary shape causing imbalance, static weights such as finger and thumb weight were much more relevant to ball reaction.

When drilling a ball pin up, it would generally have more finger weight. This caused the ball to get down the lane a bit further. When you drilled a ball pin down, it would generally have more thumb weight. This caused the ball to react a bit sooner. The static weights were much more influential because there was nothing else inside the ball for gravity to influence.

Fast forward to today’s game. Take a look at Figure 1 again. The picture on the right shows the inside of a modern day bowling ball. We now have large, dense, and dynamic shapes that dominate ball reaction. We can now create vastly different reactions using different drilling layouts. The laws of physics cannot be broken. Our main concern with the powerful cores of today’s game is the radius of gyration (RG) and differential (Diff). These two work together with other variables to create 3 distinct phases of ball motion as the ball travels down the lane. While there are other variables influencing these phases of ball motion, we are going to hold them constant for the time being and focus on this piece of the puzzle.

The Pin Buffer

Before we understand what the reaction differences between pin up and pin down layouts are, we need to know what is actually changing in the layout that causes the pin to be above the fingers compared to below the fingers. Take a look at Figure 2. It may look like a lot to take in at first, but it's a great illustration of the difference between pin up and pin down. We can have two different balls with an identical Pin-to-PAP distance and MB-to-PAP distance, but one has the pin above the fingers the other has the pin below. The cause of the change is the final measurement in Storm's Pin Buffer Layout System, the pin buffer. Shorter pin buffers are going to raise the pin because they have to be closer to the VAL. This is seen in the ball on the left in Figure 2. Longer pin buffers are going to lower the pin because they have to be further from the VAL. This is shown by the ball on the right in Figure 2. The only difference between these two balls is the pin buffer. The ball on the left has a 2" pin buffer, while the ball on the right has a 4 1/2" pin buffer.  You can see that the pin is forced further down the farther away it gets from the VAL and further up when it is closer to the VAL. Now that we understand what is causing the difference in the layout, let's take a look at some of the key differences in dynamics that result from putting the pin above the fingers compared to below.

Removing the Mass

When drilling a bowling ball in today’s game, it is important to note where the mass is being taken out of the core. Every hole you introduce to the ball is going to alter the shape of the core. This means the RG and differential are both going to change from the undrilled number. Refresh your mind by looking at Figure 3. As we know, the pin is the designation for the x-axis on the surface of the ball. It is the very top of the core. Approximately 6 3/4" away from the x-axis is the y-axis. This is 1/4 of the ball and gets us directly into the side of the core. Total differential is measured as the difference between the x-axis and the y-axis. Essentially it is a measure of the difference between the height and width of the core. The larger the difference, the higher the total differential. More differential means that there is the possibility for more imbalance and flare if the core is positioned appropriately from the PAP. Getting back to the topic of this article, let’s take a look at how we change these core dynamics with pin up and pin down layouts.

Take a look at the example that we have shown in Figure 4. It's a basic example, but you'll notice the pin is above the fingers. This is going to result in the holes being drilled more to the side of the core. This means that more mass is going to be taken out of the side of the weight block than the top. This is essentially making the weight block thinner than it was originally. The larger the hole, the more influence it is going to have. You'll notice on most pin up layouts, the thumb hole ends up being close to 6 3/4" away from the x-axis. As you can see, this increases the difference from the x-axis to the y-axis. This raises the total differential and keeps the RG lower than it would be if the holes were in the top of the weight block. We know a lower RG ball is going to transition faster because it is less resistant to changing direction. Think of an ice skater with their arms in. They spin extremely fast because a majority of the mass is located towards the center. This is going to result in the ball revving up faster and flaring more. Overall, this will make the ball stronger and transition faster off the spot.

Take a look at the example that we have shown in Figure 5. A pin down layout is going to result in the holes being drilled more on the top of the core. This means more mass is going to be taken out of the top of the weight block than the side. This is essentially making the weight block shorter than it was originally. You can see how you are now moving the thumb hole away from the y-axis and drilling the fingers nearly on top of the x-axis. As you can see this decreases the difference from the x-axis to the y-axis. This lowers the differential and raises the RG. We know a higher RG ball is going to transition slower because it is more resistant to changing direction. Think back to the ice skater. If they put their arms out, more mass is away from their center. This makes them slow down and requires more energy to be added in order for them to spin at the same rate as they did with their arms in.  This is going to result in the ball revving up slower and flaring less. Overall, this will make the ball weaker and transition slower off the spot.

Finishing Up

The days of a pin up ball going farther down the lane and a pin down ball starting sooner are gone if we hold the other variables constant. The changes in bowling ball technology over the years have significantly altered how drilling the bowling ball will influence ball reaction. These large dynamic shapes now dominate ball reaction and overpower static weights. Modeling these two different layouts on our engineering software, we were able to change the differential a significant amount. Prior to drilling, a 15lb Velocity Core has a differential of 0.051. When we modeled the pin up layout, the differential went up to approximately 0.057. When we modeled the pin down layout, the differential went down to approximately 0.035. As you can see, where the mass is taken out of the weight block and how large the holes are makes a tremendous difference on the specs of the core. The main idea of this article is to get you thinking about the cause and effect of drilling a ball in today’s game. Every hole you introduce to a ball is going to alter the shape. Are you altering the shape in a way that matches up to how you throw the ball or what you bowl on? Again, we know that there are many more pieces to this puzzle. All we can do is take a look at each of the pieces one at a time to fit them all together to see the entire picture.


PIN-to-PAP Distance

Decisions Decisions

There are many decisions that need to be made after purchasing your newest bowling ball. All of them are pieces of a puzzle that fit together properly to create good ball motion. The Pin-to-PAP distance is going to be the first and one of the most important decisions that should be made regarding the layout. Of the changes you can make to a layout, Pin-to-PAP distance is going to have the greatest effect. If you are starting to build a new arsenal, it is best to take a look at some of your current equipment to see what types of Pin-to-PAP distances you have been utilizing. You may notice you prefer certain distances over others. You might find that all of your equipment utilizes a similar distance. Does that distance match up well to your ball speed/rev rate or the conditions you are bowling on?

Pin-to-PAP distance might happen to be the piece of the puzzle that was missing for you.

After reading this article, you may begin to understand why you struggle on certain conditions. The goal of this article is to open your eyes to experimenting with different Pin-to-PAP distances to create different shapes. Let’s take a look at some background information on what the Pin-to-PAP distance is and how it affects ball reaction.

 

Orientation of the core

The Pin-to-PAP distance (appropriately enough) is the distance from your positive axis point to the pin. It is going to control how much of the core's flare potential you utilize in the bowling ball. It is controlling how the core is oriented at the moment of release. The Pin-to-PAP distance can range anywhere from 0 to 6 ¾". You might notice that this is approximately 1/4 of the bowling ball. We have turned the coverstock and core translucent in the above figures to show you the orientation of the weight block with different Pin-to-PAP distances. It's important to note that these do not take into consideration axis rotation or axis tilt. They are simply rolling forward with 0 degrees of both axis rotation and axis tilt. Figure 1.1 shows the position of the core at release with a 0" Pin-to-PAP distance. We've put a green dot on the weight block to aid in visualizing the rotation since there is minimal movement. This illustrates how stable the weight block is upon release and why it doesn't create a significant amount of track flare. It is rotating around the lowest RG axis. Skip over to Figure 1.3. Once again the weight block is in an extremely stable position. It is standing completely up rotating around the highest RG axis. Figure 1.2 illustrates the rotation of the weight block exactly halfway between these two points at 3 ⅜". The weight block will be in the most unstable position because it is sitting at a 45-degree angle inside the ball at the release point. This is going to result in the highest amount of track flare that particular core can produce. Different cores are going to produce different amounts of flare depending on the amount of total differential in the shape of the weight block inside of the core. Simple shapes can produce as little as 1" of flare. More complex shapes can produce upwards of 6" of total flare on the bowling ball. Now that we know the flare potential of the bowling ball can be manipulated using different Pin-to-PAP distances, we need to see what happens on both sides of the RG curve to understand why a ball can flare the exact same amount, but give us two completely different shapes down the lane.

 

Strong pin-to-pap

Figure 2 shows the general position of the core with a strong Pin-to-PAP distance. You can see that a Pin-to-PAP distance of 3 ⅜" utilizes 100% of the core’s flare potential because it is sitting in the most unstable position at the point of release. This is going to cause the core to wobble more than any other position which produces the most track flare. Stronger Pin-to-PAP distances are going to give you a strong predictable motion that you can count on in the midlane. This can be good in many different situations. One that comes to my mind is when the lanes are transitioning and you need something to blend out the pattern. Depending on the lane surface and volume of the oil pattern, you can even get away with these stronger Pin-to-PAP distances on some shorter patterns because it revs up strong in the midlane and blends out the end of the pattern. If we move up the curve, we increase the distance from 3 ⅜" towards 6 ¾" we utilize the higher RG side of the curve. As we get closer and closer to 6 ¾", the flare potential in the bowling ball is lowered because we are putting the core in a more stable position. This results in the ball hooking less and later down the lane. This happens because we are standing the core up in a more stable position about the higher RG axis. The higher the RG, the more resistant the ball will be to changing direction as it travels down the lane. Using longer Pin-to-PAP distances is going to raise the RG and promote a slower transition with a cleaner shape through the front part of the lane. You will see more change in direction down lane with longer Pin-to-PAP distances.

 

long pin-to-pap

Figure 3 shows the general position of the core with longer Pin-to-PAP distances. In general, longer Pin-to-PAP distances are good to use on the burn when you need the extra tumble through the front part of the lane. The ball is going to want to conserve energy much longer and transition slower. As soon as the bowler releases the ball, the energy the bowler imparts on the ball will begin to be lost. Controlling how quickly the energy is lost is crucial to creating good ball motion. There are more variables than just the Pin-to-PAP distance that influence the rate that energy is lost, but for this article's purpose we are simply looking at this one piece of the puzzle. Using too strong of a Pin-to-PAP distance when the pattern is extremely dry will result in the ball losing too much energy too early on the lane. It is going to be very difficult for the ball to get through the pins properly when it has used up a majority of its energy in the front part of the lane. We only have 15lbs of ball to knock down 34lbs of pins. We need the ball to be in the proper phase of ball motion at the correct entry angle to win the battle. To accomplish this, you'll want to make sure you are using longer Pin-to-PAP distances when the lanes are drier to promote a cleaner look through the front with more energy down lane. This will allow the ball still have enough energy to make it around the corner and get through the pins properly. Keep in mind there are always exceptions in our game, but this gives a good generalization to get your mind headed the right direction.

 

short pin-to-pap

Figure 4 shows the general position of the core with shorter Pin-to-PAP distances. The more we begin to decrease the distance from 3 ⅜" towards 0" we utilize the lower RG side of the curve. As we get closer and closer to 0", the flare potential in the bowling ball is lowered because we are putting the core in a more stable position. This will result in the ball hooking less and earlier on the lane. This happens because we are lying the core down in a more stable position about the lower RG axis. The lower the RG, the less resistant the ball will be to changing direction as it travels down the lane. Using shorter Pin-to-PAP distances is going to promote a faster and smoother transition through the front part of the lane. You will see a much earlier roll with not much direction change down the lane if you utilize shorter Pin-to-PAP distances.

In general, this would be good to use on either the fresh, or a very short pattern where you are looking for control off the end of the pattern. The ball is going to get into a roll extremely early because the core is laying in such a stable position around the lowest RG axis. This means that it will use a lot of its energy early and smooth out the reaction down lane. This can be great when the lanes are really flat and you are looking to stay out of trouble. You will get a smooth predictable reaction out of shorter Pin-to-PAP distances. Of course, it could be a bit of a challenge to get them to go through the pins properly because so much of the energy is used in the front part of the lane. Remember, we have a 15lb ball against 34lbs of pins.

Luckily modern day bowling balls cause lane patterns to transition extremely fast.

The bowler should be able to move from these shorter Pin-to-PAP layouts to other layouts that will give them more shape down lane. Shorter Pin-to-PAP distance layouts definitely aren't what you want to have on every ball, but they can save you from the dreaded 150 game on the fresh or when the pattern is extremely difficult. That could be the difference between winning and losing. It's not always the ball that you throw in the finals that got you the win. Sometimes the unsung hero is the ball that keeps you out of trouble when the lanes are tough. A good arsenal is always going to have at least one shorter Pin-to-PAP distance ball for control.

Symmetrical verses Asymmetrical

One final topic that must be addressed when discussing Pin-to-PAP distance is the different effects it has on a symmetrical ball verses an asymmetrical ball. Figure 5 shows the difference between a symmetrical shape and an asymmetrical shape. Since an asymmetrical ball has the presence of a preferred spin axis (PSA) there can be significant differences when using longer Pin-to-PAP distances. These differences depend on the location of the PSA. If the ball driller puts the PSA in a weak position, longer Pin-to-PAP distances will react similar to a symmetrical ball. If the PSA is placed in a strong position, the ball will actually flare more with longer Pin-to-PAP distances than they will on a symmetrical ball. This is just another example of how much more versatile some of those asymmetrical shapes are. They can be fine-tuned further than a symmetrical ball to get a closer match to what you are looking for.

Wrap-up

Concluding this article, we can see that the Pin-to-PAP distance is a powerful tool in creating proper ball motion. It controls how much flare and what side of the RG curve we use. A problem many bowlers have when they run into issues with carry is their ball either still hooking or being completely rolled out at the pins. There is a small window in there where the ball is in a strong roll. A ball is always going to transfer more energy if it is rolling through the pins. We are bound by the laws of physics in our world. We have 34lbs of pins is standing in the way of a 15lb bowling ball. The pins are always going to win unless we get the ball into the roll phase at the correct time and at the proper entry angle. Pin-to-PAP distance is going to help you control how much energy your ball has and where it begins to use it so you can begin to create the proper shape and entry angle. Always be sure to have a few different Pin-to-PAP distances in your arsenal to be sure that you can create the right amount of flare for anything you are bowling on. As previously stated, there are many more variables that influence ball motion. This article looked solely at Pin-to-PAP distance and held other variables constant. This is just one piece of the puzzle to creating good ball motion. Future articles will cover other pieces of the puzzle to help you understand the entire picture.

 

 


Balance Holes

Background

A balance hole is an extra hole in the bowling ball that is not used for gripping purposes. Balance holes are primarily used to make the ball static weight legal to the current USBC Equipment Specifications and Certifications Manual if they are outside the legal limit after drilling. Once a bowling ball has been drilled, there are still options to fine-tune the reaction for the bowler. This article is going to look at how balance holes can be used to alter the reaction of a bowling ball.

Traditional thinking

Balance holes can influence ball reaction depending on the size and the location of the hole. Before reading this article, take a look at your current equipment. Do any of your bowling balls currently utilize a balance hole? If so, was there any thought put into the location of it, or was it simply to make the ball static weight legal? You may notice that you really like a ball with a certain location and size of balance hole, but it might not be your favorite on a different ball. Why is this? Let's examine.

Traditionally, balance holes were presented in very simple terms. Historically, the higher the balance hole is in relation to the midline, the more it decreases the flare potential of the bowling ball. The lower the balance hole is in relation to the midline, the more it increases the flare potential of the bowling ball. Figure 1 illustrates this. While this is mostly true, there can definitely be some exceptions. Not all balance holes in the same location are going to have the same effect on the ball. There are other variables that are going to influence how they alter the bowling ball's performance.

The term "RG" refers to the radius of gyration - a very important bowling term to become familiar with. This basically tells you how much of the mass is located towards the center of the ball.

Low RG's means more of the mass is centrally located. Higher RG's mean that more of the mass is located away from the center. Lower RG balls are going to require less energy to change direction. They will transition faster and roll earlier. Higher RG balls require more energy to change direction. They will transition slower and roll later.

Every ball is going to have both a low RG and high RG axis. Take a look at Figure 2. It's important to note that the pin is the surface designation for the low RG x-axis of the bowling ball. In general, 6 3/4" from the pin is going to be the high RG y-axis of the bowling ball. The distance from the x-axis to the balance hole is going to be crucial in determining how much and what kind of effect that the balance hole has on the reaction of the bowling ball. Shorter distances (3" or less) to the x-axis are going to decrease reaction. Longer distances (4" or more) to the x-axis are going to increase reaction. Distances somewhere in the middle are going to have little to no effect. Why does this occur? Let's take a look.

the difference in RG's

Every hole that you introduce to a bowling ball is going to raise the RG of the ball in that particular location of the hole itself. We know that the pin designates the low RG axis on the entire ball. Figure 3 represents a 15lb Torrent. Looking at the numbers, a Torrent in this weight has a low RG of 2.56 and differential of 0.044. This means at the location of the pin, the RG of the bowling ball is going to be 2.56. If we go approximately 6 3/4" away from the x-axis, we will find the y-axis. The y-axis is the high RG axis of the bowling ball. This is essentially a 90° angle from the top to the side of the core. The difference between these two axes represent the total differential of the ball. Using some simple math, we can calculate what the high RG axis of an undrilled 15lb Torrent is. 2.56 (Low RG) + 0.044 (Differential) = 2.604 (High RG). It is important to note that the RG of the ball is going to change as we move across the surface of the ball. Somewhere in between 0 and 6 3/4", the RG will be somewhere between 2.56 and 2.604. The shape of the core primarily influences this. Now that we know the RG's of the Torrent, we can take a look at how balance holes are going to influence them.

 

 

Distance from the x-axis

Let's start with hole placements with shorter distances from the x-axis. Imagine putting an extra hole directly through the pin as an extreme example. We know that introducing a hole into the ball is going to raise the RG of the ball in that particular spot. The x-axis is the lowest RG spot on the entire ball. If we add a hole to it, we are raising the RG of the lowest RG spot on the ball. This makes the lowest RG spot on the ball higher and closer to the high RG axis. This is lowering the total differential between the two, which makes the ball weaker and respond slower as it transitions down the lane. Think about where the mass is being taken out of the core. The pin is designating the top of the core. If we drill a hole directly through the pin, we are taking more mass out of the top of the core. This essentially makes the core shorter, which lowers the total differential and raises the overall RG.

Now let's take a look at hole placements with longer distances from the x-axis. Imagine putting an extra hole 6 3/4" away from the x-axis. As always, when introducing a hole into the ball, that hole is going to raise the RG of the ball in that particular spot. Approximately 6 3/4" away from the x-axis is the high RG axis. If we put a hole on the high RG axis, we are raising the RG of the already high RG axis of the ball making it even higher. What is this going to do to the overall differential? The low RG axis remains unchanged, but now the high RG axis is even higher. The total differential has increased and the RG has remained lower. Imagine where the mass is being taken out of the core with the hole 6 3/4" from the pin. All of the mass will be removed from the side of the core. This is going to make it skinnier than it was before compared to its height. This will increase the total differential and keep the overall the RG lower.

Finally, let's take a look at medium distances. If we put an extra hole at 3 3/8"away from the X-axis, we are precisely between both the low RG axis and high RG axis. This is going to have little effect because we are taking mass out at a 45° angle relative to each axis. We are taking mass out of the top and the side which cancels out the effect. If we get farther than the 3 3/8" distance, we remove more mass from the side. If we get closer than the 3 3/8" distance, we remove more mass from the top. Each of these effects have been outlined above and should make sense.

Sizes are pretty self-explanatory. As you can imagine, the larger and deeper the hole, the more effect the hole will have on the reaction of the ball. This is because we are removing more mass out of the core. This means there are a lot of options when it comes to size and depth. I always suggest starting with a smaller hole because you can always increase the size based on what you see from the initial ball reaction.

 

Position on the arc

The final variable to look at is the position of the balance hole on the arc. Let's imagine that we put an extra hole in the ball 5" from the pin. There are many different positions on the ball that are 5". Looking at the Figure 4, we can place a balance hole anywhere on this arc and it will remain 5" from the pin. The further out we put the hole towards the VAL, the more we are going to smooth out and slow down the reaction. This happens because the holes are further apart. The closer we get the hole towards the thumb, the faster this ball is going to transition. This happens because the holes are closer together creating a larger intermediate differential after drilling. It is important to note that you always need to make sure that tracking issues won't occur when determining where to place the balance hole. You will always want to throw the ball first and make sure you aren't placing the balance hole near any track flare. Keep in mind, if you are using a flare increasing hole (4" or more), the ball is going to flare more after the hole is drilled. You will need to put the hole further away from the flare rings.

 

 

Looking at balance holes like this makes it easier because it gives you consistency from ball to ball. The mass is being taken out of the same spot on the weight block to create a more consistent reaction regardless of the differences in layout. In Figure 5, the ball on the left is drilled 3 x 4 x 1 and the ball on the right is drilled 6 x 4 x 3. If both balls were to have a balance hole located on the PAP, the balance holes are not going to have the same effect on each of the balls. It's going to increase the total differential and lower the RG on the 6 x 4 x 3 ball because the balance hole is 6" from the pin. On the 3 x 4 x 1 ball, the balance hole is going to have less of an effect because it is drilled in the neutral zone of 3-4" from the pin. Keep in mind, all of this information is relative to all of the other pieces of the puzzle. Remember that Pin-to-PAP distance is going to be another variable influencing the reaction. Clearly a ball with a 6" pin-to-PAP distance is going to be cleaner through the front part of the lane and flare less. The location of the hole is one of the secondary factors that goes into ball reaction.

 

 
symmetrical verses asymmetrical

The last thing we cannot ignore is the effect of hole placement on a symmetrical versus an asymmetrical core. Take a look at Figure 6. Remember that an asymmetrical ball can be fine-tuned even further because of the presence of the PSA, or the preferred spin axis. The closer the balance hole is drilled to the PSA, the higher the intermediate differential is going to become. The ball is going to transition faster because it has a higher intermediate split. The further the balance hole is drilled from the PSA, the more intermediate differential you are drilling out of the ball. Essentially, you are drilling out some of the asymmetry which makes it transition slower as a symmetrical ball would. All the other principals aforementioned are the same regarding balance hole distance from the x-axis.

Essentially, if we put a 1 1/4"  hole 6 3/4" away from the pin and drill it 3 1/2" deep, we are going to significantly increase the total differential and lower the RG of the ball. This is going to result in it transitioning much faster and hooking more front to back and right to left overall. If we put a 1 1/4" hole through the pin drilled 3 1/2" deep, we are going to significantly decrease the total differential and raise the RG of the ball. This is going to result in the ball transitioning much slower and hooking much less front to back and right to left. If we decrease the size or the depth of these holes, we will reduce the impact that they had in their respective locations.

summary

In summary, you can really see how much of an effect can be created using different balance hole locations and sizes. Hopefully now, you have a better understanding of how balance holes further from the x-axis increase flare potential and balance holes closer to the x-axis decrease flare potential. Keep in mind that there are many pieces to the puzzle that is laying out a bowling ball. Some are more influential than others. This article strictly looks at the effects of balance holes and keeps all other variables constant. Learning more about how these variables work together to create good ball reaction is crucial to understanding what your ball is doing as it transitions down the lane. Knowledge is power - put them all together and you've got some serious power.

Always remember: not all balance holes are created equal!


Knowing Your Roll

Why It's Important

There are many variables that can affect the way your ball rolls. Some are related to the way you release it and your unique delivery. Other variables can be credited to that evil lane man and how he conditions the lane. Then there are factors that are above and beyond anyone’s control, and, no matter how hard you try, you cannot change them. We are going to discuss the subtle distinctions in how you roll the ball that play a bigger role than you might think. Understanding these characteristics will help you in choosing your next ball and, furthermore, help your pro shop operator decide a layout for your brand new toy.

Did you know that your ball actually decelerates as it travels down the lane?

The chemical composition in conjunction with the surface preparation of the coverstock matters greatly. A solid coverstock with a low grit surface texture will lose speed at a higher rate than a polished, pearlized coverstock. Friction reduces ball speed, so this actuality is highly linear with that of wood lanes or lanes that have not been oiled in a long time. In the published Ball Motion Study conducted by the United States Bowling Congress, the ideal bowling ball speed is about 17 miles per hour measured at impact with the pins and about 20-21 miles per hour when the ball is released onto the lanes. Bowlers with high ball speeds and without the revs to match can be considered “speed dominant.” They will typically favor more aggressive surfaces and layouts to help their ball pick up sooner on the lane. “Rev dominant” players with slower ball speeds typically like less aggressive balls, layouts, and surfaces to help prevent their ball from overreacting.

 

What is rev rate?

Rev rate is a calculation of the amount of revolutions a bowler imparts on a ball. The common unit used is revolutions per minute, or RPM. Over the years, bowlers have generalized the RPM gamut into three categories: stroker, tweener, and cranker. Understanding your rev rate (and its relationship with your speed, axis tilt/rotation) is important because it helps to categorize your specific needs as a bowler. Knowing what type of ball to buy, what techniques need to be applied, or the type of wrist device needed all depend heavily on your rev rate.

 

What is axis tilt?

Axis tilt is the vertical angle at which the ball rotates. Commonly known as spin, axis tilt is determined by the position of the thumb during the release. If the hand turns too early, the thumb exits on top of the ball. Bowlers with a high degree of axis tilt will be able to see the top of their hand during the release and follow through. The resultant path of a ball with a higher degree of axis tilt is extended and the amount of backend potential is reduced. Oily lanes become quite difficult when the core is rotating in a vertical fashion, but is actually favored on drier lanes. Being able to have the thumb exit at the bottom of the forward swing minimizes axis tilt. The lower the axis tilts, the sooner the ball will enter its roll phase before making impact with the pins.

Axis rotation is the horizontal measure of the angle of the ball's revolutions, and much like axis tilt, it is also determined by the bowler’s release. Axis rotation is commonly known today as side roll. When the ball has no axis rotation, the fingers exited directly underneath the ball at the 6 o’clock position. End-over-end roll (0° of axis rotation) removes all hook potential from the ball regardless of the amount of revolutions, speed, or lane conditions. High amounts of axis rotation (90° of rotation) will cause the ball to skid further, but unlike axis tilt, will cause an intense hook angle at the breakpoint.

Players with high amounts of axis rotation will favor drier lanes, and lower amounts of axis rotation usually like more oil. Higher amounts of friction will cause the ball to lose axis rotation at higher rates. Initial axis rotation, ball speed, axis tilt, and lane friction all dictate when side revolutions become end-over-end revolutions. Generally speaking, balls skid, then hook, then roll. Less rotation will shorten the skid phase and get the ball into the hook phase earlier, while maximum rotation will extend the skid phase of the ball and increase its hook potential down lane. Manipulating your axis rotation is a valuable tool because it will change the ball’s reaction while still allowing you to stay in the same part of the lane and use the same break point. Ideally, you would like to limit lateral moves on the lane because it forces you to make multiple adjust­ments. And often, particularly on challenging conditions, the zone you’re going to have to play and the break point are pretty defined.

Through practice, you can alter or enhance your ball speed, rev rate, axis tilt, and axis rotation.  The best bowlers in the world have the ability to manipulate any and/or all of these at a moment’s notice. Technology of the sport today only enhances the subtleties of your game. Rubber balls and wooden surfaces did not place an emphasis on shot making versatility.  Ball technology and oil patterns of the modern era force quick-changing conditions and different parts of the lane to be utilized that were not in play thirty years ago. Knowing your roll is more important now than ever before.