Effects of RG and Differential

Did you know that RG and differential have a huge effect on ball reaction? Knowing just some of the basics can really help you choose the right equipment for your game.


RG stands for ‘Radius of Gyration’ and is defined as the distance from the axis of rotation at which the total mass of a body might be concentrated without changing its moment of inertia. Simply put, RG dictates when the core begins to rev up. Weight blocks can be designed in many different shapes, such as light bulbs, diamonds, ovals, footballs, etc.


A football is an ideal concept to explain how a weight block functions. The football can spin easily either end-over-end or as a spiral. It would take longer to make one rotation at the same speed end-over-end than it will rotate as a spiral because the radius of the former axis is longer than the spiral axis. This means the end-over-end axis is rotating in the high RG plane and the spiral axis is the low RG plane.


Within that shape, RG is determined by the location of the majority of the mass. The lower the RG number, the earlier the hook. High RG means the exact opposite: the higher the number, the more length the ball will create. When we see the RG number advertised on a ball box, they provide the low RG plane number. This is industry standard across the board for all balls.


RG ranges from 2.460” – 2.800”

  • 2.46” - 2.51” (Lower RG)
  • 2.52” - 2.56” (Medium RG)
  • 2.57” - 2.80” (Higher RG)


With a better understanding of RG, it’s now time to discuss differential and its effects on ball reaction. We define differential as the difference between the maximum and minimum radius of gyration, better known as the X and Y-axes of the weight block. RG-differential indicates the bowling ball's track flare potential. Therefore, the higher the differential, the more the ball will flare. The more flare on a bowling ball, the more the bowling ball cover touches the lane surface. With more of the surface touching the lane, the earlier the ball wants to hook. With low flare, less of the ball surface touches the lane causing the ball to create more length due to the surface rolling over the same part of the bowling ball which is now covered in oil. Less surface equals less friction promoting more length.


Differential ranges from 0.000” – 0.060”

  • 000 - 0.025 (Lower Flare Potential)
  • 026 - 0.046 (Medium Flare Potential)
  • 047 - 0.060 (Higher Flare Potential)


How will these factors affect my decision in choosing the correct ball for my game? For this example, let’s use the Storm Proton PhysiX™ which has an RG of 2.48 and a differential of .053. Based on the value chart we used earlier, this is a lower RG/higher differential ball that will want to get into an earlier roll while providing plenty of flare. In addition to the sanded-solid coverstock, this will likely be the strongest ball in your arsenal. This ball performs best in fresher, high-volume conditions.


Now compare the Proton PhysiX to the Hy-Road™ Pearl with an RG of 2.57 and differential of .046. The Hy-Road Pearl features a much higher RG and slightly lower differential, which suggests this ball will provide much more length and less flare overall. The Hy-Road Pearl will maintain a straighter line longer than the Proton PhysiX. This type of ball will be most suitable for higher friction conditions.


The !Q™ Tour Emerald is a unique example. The RG is 2.49 with a differential of .029. Just based on the numbers, this ball wants to roll early, but it will create natural length with low-medium flare potential. Coverstock plays the most crucial part in ball reaction because of that combination. Since this ball features a 1500-grit polished finish, this ball will have length and a strong, yet controllable down-lane motion. However, if you were to take away the polished finish, it would yield a smoother backend reaction.


This information just scratches the surface of core dynamics, but hopefully, this helps simplify the selection process of your next Storm ball.


How to take advantage of Surface Preparation

This article will discuss some of the best ways for you to maintain your bowling equipment. We’ll also focus on tips and tricks to create the desired surface and ball reaction.

Coverstock adjustments can make all the difference in your overall ball reaction, but why? Weight block, layouts, and ball dynamics play a significant part in general ball reaction, but keep in mind that the ball's coverstock is touching the lane and interacting with the lane oil. Therefore, making surface alterations will play a significant role in affecting your ball reaction. Adding the appropriate surface to match the lane condition can make the difference in 5, 10, or even 20 pins a game.

Firstly, we’re going to discuss the daily maintenance that should be done on your bowling equipment. You need to be sure you’re wiping your ball off in between shots with a shammy or towel. This practice will do two things: It will slow down the oil absorbing into the coverstock by removing it after each throw and provide a clean surface for your ball. Nothing is more frustrating than leftover oil on your ball causing you to leave a pesky 10 or 7 pin. When you’re finished with your bowling session for the day, you’ll need to clean the ball with a towel (microfiber if possible) and your desired ball cleaner such as Reacta Clean, Xtra Clean, True Blue, or Reacta Foam. These are excellent products to remove all the dirt, grime, and oil from your bowling session. This will also restore the tacky feel to the coverstock that delivers a consistent reaction.

Next, we will be focusing on the use of Abralon pads and how to create surface texture on the coverstock. You can make surface adjustments by hand or on a ball spinner. Each Storm, Roto Grip, or 900 Global ball comes with a particular factory finish which can be found on the box of each ball. Keep in mind that this is the suggested surface for that ball, however, it can be adjusted to better match your game. For example, the Proton PhysiX comes out of the box at 2000-Grit Abralon. Suppose you’re a player with softer speed and have trouble getting the ball down the lane. You can make a slight adjustment with a 4000-grit pad or a small amount of polish to match your unique style for that ball. Adding surface to the coverstock could completely alter the ball's reaction, leading to a successful line to the pocket. This could give you a significant advantage on the field with just one minimal adjustment.

The beauty of surface changes is that there are virtually endless options you can create. Don’t be afraid to try unique surface preparations that might work for your style on that any condition. Some noteworthy surface changes could be taking the ball down to 1000-grit and immediately adding a layer of polish. This will create a cleaner but smoother and predictable motion on the ball. Next, try taking one of the weaker balls in your bag and add a 1000 or 2000-grit Abralon surface. This allows you to play straighter and create a controllable reaction on fresher conditions. One last surface suggestion is what we call a "sheen." This is when you surface your ball to 500-grit for 30 seconds, then 3000-grit for 10 seconds, and finish with a light coat of polish.

As bowlers and competitors, we’re continuously looking to increase our scores and create the most performance out of our equipment. Focusing on maintaining your coverstock and building surface textures to fit the condition will single-handedly produce higher scores and more consistent results.

Making the best of your practice session

In this article, we are going to discuss a vital part of improving your game: practice, practice, practice. Too many bowlers, the idea of practice could be a daunting or misunderstood task. We’re all guilty of throwing shot after shot for hours without a goal to accomplish or feeling like we don't have enough time to work on our game.  Throughout this article, we’ll talk about what tools you can use to improve your physical game and how to best use your time when on a strict schedule. In addition, we’re going to lay out a detailed plan depending on how much time you have whether you have less than 20 minutes, between 20 minutes and an hour, or more than an hour.

The first and most important facet of practice is creating structure within your practice. Creating a plan will help you use your time wisely and get the most of your practice session. There will be two training details that will stay consistent with all three of the time options: drills and not keeping scores.

So, you have around 20 minutes for a practice session, and you’re looking to take full advantage of that time. Let's start by splitting your 20 minutes into two ten-minute sections. The first ten-minute section will be dedicated to drills and pinpointing one aspect of your game you want to improve. For example, if you're going to improve your balance at the line, do 10 minutes of one-step drills and focusing on a stable finish position. Once the first ten minutes have been completed, we now take what was focused on during the drills and incorporate that into a full approach to finish out the practice session.

Let’s now outline the structure for our 1-hour session. For this time frame, we will maintain the same focus for drills and further expand from there. This is the time you can better your game by working on something you consider a weakness. For example, if you struggle with creating an end-over-end ball roll, you can spend about 30-40 minutes of that practice session focusing on that improvement. The most prominent mistake bowlers can make when practicing is working on multiple changes at one time. When you take the time and dedicate your focus to one singular improvement, this will help you see a significant amount of progress in an hour-long session. If available, video recording your session is key. This way you can watch the progress and note improvements from start to finish.

Say you have 1-2 or more hours to practice. We’re going to start with utilizing the advantage of drills. No matter the amount of time you have, drills will always be a great way to start a practice session. This helps reinforce good mechanics and solid fundamentals. Once the drills have been completed, there are a few more elements that we can incorporate to get the most out of our practice. As you know there are many ways to manipulate a bowling ball, and within this allotted time, we can work on versatility. A few skills that can be developed are increasing and decreasing axis rotation, lofting the ball, increasing and reducing ball speed, manipulating rev rate, and increasing and decreasing axis tilt. If you can become comfortable with making these changes when the lane pattern is calling for it, you’ll have a better chance to maintain hitting the pocket as the lane continues to transition. We can now finish up this practice session with spare shooting. Working through a practice spare cycle is a great way to wrap up a practice session.

As we can see, practice is a crucial part of improving your game. These are just a few ideas that can help structure your practice and get the most out of your time. Practicing is not a one size fits all experience; you can get as creative as you like to better your game and enjoy your practice on the lanes.



One of the most exciting times as a bowler has come. It’s time to drill a brand-new Storm bowling ball! There’s no better feeling than walking into your pro shop to drill a new piece of equipment. The importance of choosing the right drilling is key to get the full potential of that ball. Many resources can be used to help map out the correct layout. There’s one piece of information that many bowlers overlook when researching information on their new ball. That is, of course, the label on the bowling ball box. In this article, we’ll discuss each detail on the label and how this information can help decide the correct layout.

At the top of the label, you will find the name of the ball. For this example, we featured the Storm Incite. Just under the ball number, you will find the logo image engraved on the ball. Depending on the color scheme and the name of each color of the ball, you will find the color pallet as the backdrop of the logo image. This will then be followed by something that separates Storm from other ball manufacture brands, and that is going to be the fragrance name feature on that Storm ball. The Incite features a Cherry Vanilla as the scent.

Diving into the information and specs of the ball, we are first going to give attention to the gross weight. This displays the overall weight of the undrilled ball. Just under the gross weight, you’ll find an image of the ball's core. Top weight is a term used to refer to the weight difference measured from the top half of a bowling ball compared to the bottom half of the ball. The pin distance refers to the distance between the colored pin and the CG (center of gravity) marking on the ball. In this case, the Incite has a top weight of 2.50oz and a pin distance of 2.5-3-inches. This is valuable information when deciding the layout of the ball.

Continuing down the label, we’ll find the coverstock and ball finish. For this example, the coverstock on the Storm Incite is R4S™ Hybrid Reactive finished at 3000-grit Abralon. This coverstock is wrapped around the new asymmetric Tensor™ Core. This information is followed by the RG (radius of gyration) and differential of the ball. The Incite’s RG and differential is 2.50 and 0.053 respectively in 15lbs. The next question is, what is does RG and differential mean, and how does it affect your ball reaction? Simply put, the higher the RG, the later the ball is going to hook, or transition and the lower the RG the earlier the ball is going to hook. The overall differential will affect how much the ball will hook. The higher the differential, the more the ball is going to hook.

Now we’re going to breakdown the meaning of the serial number on the ball. The first two digits represent the year the ball was manufactured followed by the three letters of the SKU (Stock Keeping Unit) of the ball. This is the individual SKU for this ball and we can track this ball in our inventory. The next character is the letter for the month. “A” represents January, “B” is February, “C” is March, and so on. The next two characters will identify the day of the month, followed by the letter representation of the engraver it was engraved on, and the final three numbers represent the ball number that came from that engraver for the day. Finally, the very bottom of the label features the barcode, website, and the ball's full SKU as the last part of the label.

Getting a new ball will always exude confidence and excitement for every bowler. With all the excitement, the question still stands: "How should I drill this ball?" Always keep in mind there’s plenty of useful material about your new ball on the box label. Before you toss that box away, be sure to utilize all the valuable information you can about your new ball.


How to Read a Lane Pattern Graph

Have you ever found yourself in a situation where you have arrived at your next tournament, paid your entry fee, and notice there is a lane pattern graph? The only problem is, you are not completely sure what you are looking at or how to read that abundant useful information. This article will explain each piece of the lane graph’s importance and how it will impact your lane play.

Pattern Distance:

First, we want to review the pattern graph from top to bottom, starting with the oil pattern distance. For this example, we used the 2020 Storm Utah Open Pattern. We can see that the overall pattern distance is 41ft. This distance falls into the medium pattern category. Now armed with this information, we know there could be multiple attack angles to get to the pocket. Typically, on shorter patterns that fall between 32 feet and 36 feet, bowlers are forced to play the outside part of the lane. In contrast to the longer patterns, 43 feet and longer bowlers are forced to play the deeper inside part of the lane. Therefore, the pattern distance between 37 feet and 42 feet allows the bowler to play multiple angles depending on your ball choice and style.

Pattern Volume:

The next part of the lane graph we will discuss is the Volume Oil Total, better known as the thickness of the oil, applied on the lane. This will be the overall combined volume of oil between the forward oil and reverse oil. As we see in the photo provided, the forward oil total is 20.295 mL, and the reverse oil total is 10.26 for a round total volume of 30.555 mL of oil. Based on today’s standards, this would be considered a higher volume pattern. In comparison, most house patterns have between 22-24 mL of oil. This information will dictate the amount of surface grit to use on your bowling ball, and a good indication of how fast or slow the pattern will break down.

Pattern Ratio:

Moving down the lane graph sheet, we are going to discuss the load structure. This will be a key component of the overall difficulty of the pattern. When using a Kegel lane machine, you have an oil head that moves back and forth at a constant rate and applies that oil to the lane from left to right. As we review the graph for the 2020 Utah Open, we see this pattern has 8 loads of 2 to 2’s. Now, what does this mean? The oil head will apply conditioner on the lane from the 2 board on the left to the 2 board on the right. The more oil applied toward the gutter means the ball will overall hook less as the bowler misses to the outside boards. Therefore, most house patterns will very little 2 to 2’s, if any at all. A typical house pattern’s ratio is around 8 to 1, while this Utah Open pattern ratio is around 1.5 to 1. This means the lower the ratio, the more difficult the pattern will play.

Oil Overlay:

In the last part, we are going to cover the oil overlay of the pattern. The image on the right of the sheet showing an overhead view of the pattern as it would look if the oil had color instead of being invisible.  This effectively shows how the lane machine is applying the oil throughout both passes of the oiling process. The darkest blue is showing the highest concentration of oil in that part of the lane. This is the part of that lane that will create the most amount skid. The teal color box labeled “forward” represents the oil applied during the forward pass heading towards the pins, while the blue box labeled reverse” is the oil applied on the pass coming back to the foul line. The final color is the light blue box labeled “buff.” The buff is once the lane machine stops spraying oil on the lane, the machine rolls out the rest of the oil to correct 41ft distance.

Preparation is key when wanting to better your game and getting bowlers ready for the next event. Having a better understanding of how to read a lane graph will help prepare bowling equipment, surface preparation, and where to start during that valuable practice time.

How to Prepare Your Tournament Arsenal

For this article, we will be discussing and outlining the steps it takes to decide the most versatile and completive 6-ball arsenal. When choosing the correct 6 balls you must keep in mind a few keys factors to ensure you are selecting the best arsenal for the event.  You want to make sure you have a good mix of RG’s, differentials, coverstocks, and surfaces. Being sure to avoid having too many of the same type of bowling ball. Each ball serves a purpose in creating the correct shape or ball motion that the lane is calling for. Think of it as a toolbox. Saws are used for cutting, a hammer is used for nails, etc. Therefore, looking at your bowling equipment in the same way will make that decision making easier.

Fresh/Benchmark Ball

The first ball we are going to discuss the “Fresh Ball”, which is better known as your benchmark ball. Usually, this ball is the first ball out of your bag when are preparing for practice. The purpose of this ball will be the blend out the wet/dry, creating a predictable motion, and provide an overall feel for the pattern. For example, if the fresh ball over-reacts, we now know we throw a weaker option and vice-versa. If the fresh ball doesn’t hook quite enough on that pattern, we now know we can throw one of our ball-up options.

Ball Up

The second and third ball in our 6-ball arsenal is going to be the ‘Ball-Up’ option. This ball is used once the lane first starts to break down and move into more oil. Typically, this ball is going to be a touch stronger overall and is going to create more shape on the lane, increasing your margin for error and producing higher scores. For the majority of players, one or both balls will feature an asymmetrical weight block.

Late Hook

The next ball up for discussion will be the “Late Hook.” This ball will be best used when the lane gets into a later transition. It  allows you to start shutting down your angles through the fronts but, will still respond when the ball gets to the dry. When the lane breaks down enough and requires you to play straighter, but you still need the ball to recover off the friction, then a ball change is needed and the ‘Burn-Ball’ which we will discuss next will be the right choice for this reaction.

Burn Ball

Now we have discussed the first 4 balls of our arsenal and next is the “Burn-Ball.” It will be the weakest and smoothest reactive ball on your bag. Its purpose is to create very little shape, allowing you to shut down your angles and play closer to the pocket. This ball will perform best when needing to play fallback, or “shim” the lane.


The sixth and final ball with be either urethane or plastic. This can be a very useful weapon when competing in tournament conditions. This will, of course, be used for spare shooting, but urethane is a great option too for fresh oil conditions, flatter patterns, and blending the wet/dry early in the event.

Keep in mind there are many variations of this arsenal that can be made. The house player can apply this to create a 3-ball arsenal, while the recreational or competitive player can use this same information to create a 4, 5 or 6 ball arsenal.

Below you will find the detailed process from our Technical Service Representative Chayton Petersen on how he decided 6-ball arsenal:

Since I’m rev dominant, my selection of balls will differ slightly than Kendle’s who is speed dominant. I have to rely upon the weight block clearing the fronts while still getting into a roll before it meets the pins. I favor high RG balls with weaker layouts so the weight block doesn’t transition as fast. I will walk you through my list of six balls I would take to a tournament based on my style.


The Phaze II is my go-to benchmark for a few key reasons. First, any good benchmark ball gives you predictability, and that’s exactly what Phaze 2 does. Its combination of low RG, high differential, and a strong cover give me a motion I can rely on with any pattern. Although rev dominant players lean towards higher RG’s, low RG’s deliver this predictable motion that I need to give me an accurate representation of how the lane is playing. Combine that with a solid, aggressive cover that blends the lane out, I know exactly where the lane hooks, where it doesn’t, and where I should be playing.

Ball Up Option 1

The Axiom is my strong ball because of NeX, Storm’s strongest cover. The Axiom digs in the best on high volume and longer length patterns. A medium-strength layout provides me just enough length to match my ball speed. Sometimes, an asymmetric ball can hook too much or too early. Since the Orbital Core is symmetric, it stays in constant motion because it doesn’t have a high undrilled PSA torqueing the ball in one direction versus another.

Ball Up Option 2

The Parallax is a great additional ball-up option for me with its unique weight block and cover combination. The higher RG, differential, and strong undrilled PSA proved me the boosted torque I need down lane when I need to move left and hook the ball. Utilizing a weaker layout on the Parallax, I’m able to keep the ball in my hand longer. As the lanes break down and I need to step left, TractionX7 gets me through the front part of the lane while offering midlane read to help me control the pocket, especially on tougher patterns. Thankfully, versatility comes in spades because the cover easily accepts surface manipulations. When I need slightly more dig, I can put some surface on the ball and get it to read the lane sooner and blend the lane out more.

Late Hook

When I need a strong motion down lane and a clean look through the fronts, the Hy-Road Pearl is my go-to ball. R2S Pearl is the best choice when the front part of the lane starts to go away. As a rev dominant player, my ball wants to read early, and that is why getting a cover as clean and responsive as R2S is will help me get the ball to the correct part of the lane. Inverted Fe2 has the highest RG of all high-performance Storm balls and thanks to its higher differential it has no shortage of movement at the end of the pattern and at the pins.

Burn Ball

The most challenging conditions I face are when the lanes get burned. I find myelf running out of room to the left, but I still need the ball to get to the pins without using energy up too soon. The Electrify Pearl fits the bill in this situation. Reactor Pearl gives me the most amount of length I can afford when the lanes get bad. Because the differential isn’t too high or too low, the Circuit Core gives me a predictable motion that isn’t too much off of the spot. I am able to square up and shim the ball off of the friction in order to not have to cross too many boards.


Storm has several urethane options for various styles. For how I like to play, I prefer to use the Fast Pitch because of its slightly cleaner look compared to the Pitch Black. It still features a higher RG than most Storm cores so that allows rev dominant players like me to keep my angles shut down. I can still shape the Fast Pitch when I need to, though. An added benefit to carrying a urethane with you at all times is doubling it up as a spare ball. This frees up a slot in my bag and adds to my overall layout versatility.

electrify hybrid vs electrify pearl

Electrify Hybrid vs Electrify Pearl


Storm is always looking to create top tier performance through the entire product line, from top to bottom. Performance should have no limitations, and with the new Electrify Pearl and Electrify Hybrid my expectations have been exceeded. In recent years, we are seeing bowlers with more rev rate and power than ever before. This equates to oil patterns breaking down and starting to transition much quicker. Staying ahead of lane transition carries more weight now; something bowlers haven’t experienced much in the past. Therefore, having the right ball to keep up with ever-changing lane conditions is a necessity.

Launch Speed: 18.5 mph

RPM: 490

Tilt: 11

Rotation: 55°

PAP: 4 ¾ x ½ Up

Layout Used for Test: 4 x 3 x 1 ½ 

Surface Used on Both Balls: 1500-Grit Polish

Oil Patterns: Beaten Path, 41’, 1:4.04, 24.25 mL; Boardwalk, 35′, 1:2.16, 28.25 mL

The Test:

For the comparison test, I decided to use two patterns to demonstrate the differences between these balls. Patterns used are Kegel’s 41’ Beaten Path and 35’ Boardwalk. For the parameters of the test I threw a total of 25 shots on SPECTO with each ball on the both patterns. With the data collected from SPECTO, I was able to average the results and create motion paths for each ball. Both balls were finished at 1500-grit polish which is the out of the box finish.

41ft Pattern test results:

When comparing these balls, the first aspect that stands out is how much overall hook these balls created while maintaining a high percentage of pin carry. The Electrify Pearl immediately gave me a look and feel that was comfortable and suited my eye quite well. I found myself unable to put this ball down, while quickly fell in love the overall performance on this 41’ Beaten Path pattern. Even with the laydown being about an arrow deeper and creating 1.2 more degree of launch angle, the Electrify Hybrid was able to maintain a consistence motion while achieving great carry through the pins.

35ft Pattern Results:

The 35’ Boardwalk pattern really allowed the Electrify Hybrid to shine. This ball reached the epitome of versatility. This is a testament to the new low RG Circuit Core. On this demanding 35’ pattern, I was able to create 4-6 boards of area down lane. The Reactor hybrid coverstock was a key component in providing the smooth, predictable, rounded motion I needed to find a repeatable line. I am looking forward to adding weapon to my bag as for the shorter and flatter patterns.


Every bowler has their favorite go-to ball, knowing that no matter what the circumstances are they have the confidence to find the pocket. I can say with assurance, I have found mine. The best part is that it comes in a pearl and hybrid. These two balls are going to be the 1-2 punch that I have been looking for to round out my arsenal. Throughout the comparison test I kept asking myself, “Are you sure these balls are in the HOT line?” The performance of these balls are unreal for the price point. As lanes start to breakdown and I start to move my feet left and balling down, I have no doubt in my mind the Electrify Pearl and Electrify Hybrid will provide the ideal reaction and the carry I need to continue striking longer.

Highlights from the test:

FloBowling - Bowling’s Best Livestream Service

As the PBA season is ramping up, be sure to tune into FloBowling to get unlimited access to the best bowling content on the planet. FloBowling will be supplying the best coverage throughout the entire bowling season.

Storm is excited to be involved with FloBowling as they are the leader in proving worldwide bowling coverage at such an affordable cost to our bowling fans. With a FloBowling subscription you will not only have access to FloBowling PRO, but all of FloSports.com that includes over 10,000 live sports events per year.

The PBA Tour telecasts will be added to the archives one week after they air on their respective networks, including CBS Sports Network, FOX Sports, and FS1.  Coinciding with the great events each week you will also get to watch many behind the scenes clips as well as interviews of our Storm Staffers and their perspective on the PBA Tour for the week and what they may have in the bag this week and all layouts.

FloBowling is a great advocate in growing the sport of bowling in that they will be able to provide more year-round live coverage of all levels of competitions on the PBA tour and more. There will be an instructional aspect as well. You will find instructional insight from many of the industry’s leading experts, coaches and professional tour representatives. This content can be accessed at FloBowling.com or on the FloSports app that can found on Apple iOS, Roku, and Apple TV.