Intermediate Differential in Bowling: How It Affects Ball Motion

Understanding core numbers can help every bowler make better choices. One ofthe most important numbers is intermediate differential. Many bowlers know aboutradius of gyration (RG) anddifferential (diff), but intermediate differential often feels confusing. radius of gyration (RG) differential (diff) Intermediate differential plays a big role in how an asymmetrical bowling ballchanges direction. It also helps you understand which ball shape matches yourstyle and speed. This guide will explain intermediate differential in simple words and show howit affects your bowling ball motion on the lane. What Is Intermediate Differential in Bowling? Intermediate differential measures the difference between the high RG axis andthe intermediate RG axis of a bowling ball. This value exists only inasymmetrical bowling balls, since symmetrical balls have almost no coreasymmetry. A symmetrical bowling ball has two RG values: the minimum RG and the maximumRG. An asymmetrical bowling ball has three RG values. The third value is theintermediate RG, which sits between the low and high RG axes. Because of thisthird value, an asymmetrical ball has an intermediate differential number. Intermediate differential can also be explained as the difference between theball’s high RG axis and its intermediate RG axis. This value is also known asthe mass bias strength. A higher intermediate differential means a strongermass bias. A lower value means weaker mass bias. Intermediate Differential Ranges in Bowling Most intermediate differential values fall between 0.008 and 0.037 inches. Ifa ball’s intermediate differential sits above 0.008, the ball is consideredasymmetrical. If a ball's intermediate differential sits below, then it isconsidered symmetrical. The ranges are: Symmetrical balls: 0.000–0.007Low intermediate differential: 0.008–0.020High intermediate differential: 0.021–0.037 Symmetrical balls: 0.000–0.007 Low intermediate differential: 0.008–0.020 High intermediate differential: 0.021–0.037 These numbers matter because they show how fast a ball responds to frictionand how quickly it changes direction. How Intermediate Differential Affects Bowling Ball Motion Intermediate differential shapes your bowling ball’s motion from the mid-laneto the pins. It does not change how much the ball hooks overall. Instead, itchanges the ball hooks. Higher intermediate differential creates faster changes A higher intermediate differential makes the ball react faster when it touchesfriction. The hook zone becomes shorter but stronger. The ball changes fromskid to hook in a very sharp way. This often creates a strong and suddenbackend motion. The ball turns fast, uses energy quickly, and may hit the pinshard if matched correctly. Lower intermediate differential creates smoother changes A lower intermediate differential creates a longer and smoother hook zone. Theball changes direction more slowly. The backend motion becomes more gradual.This helps the ball keep more energy for the pins and improves control. Both motions can strike well. The key is matching the intermediatedifferential to your style and lane conditions. Intermediate Differential vs Differential Many bowlers confuse differential and intermediate differential. They are notthe same. Differential measures the difference between the lowest RG axis and thehighest RG axis. This number shows how much the ball can flare and how manyboards it can cover. Intermediate differential measures the difference between the intermediate RGand the high RG. This number shows how fast the ball responds to friction andhow the hook shape develops. A simple way to remember the difference: Differential = amount of hookIntermediate differential = shape of hook Differential = amount of hook Intermediate differential = shape of hook Both work together, but intermediate differential gives the ball its uniquemotion shape. Symmetrical vs Asymmetrical Bowling Balls The type of core determines whether a ball has intermediate differential. Symmetrical bowling balls Have no meaningful intermediate differential.Create smooth and predictable motion.Work well for rev-dominant bowlers and slower speeds.Offer fewer layout changes since they lack a strong preferred spin axis(PSA).Symmetrical balls usually are more stable and easier to control. Have no meaningful intermediate differential. Create smooth and predictable motion. Work well for rev-dominant bowlers and slower speeds. Offer fewer layout changes since they lack a strong preferred spin axis(PSA). Symmetrical balls usually are more stable and easier to control. Asymmetrical bowling balls Have a real intermediate differential numberRespond faster to frictionCreate sharper and more angular motionWork well for speed-dominant playersOffer many layout options because the PSA is strongerThe added intermediate differential gives more shape and more ways to adjustthe core’s position during drilling Have a real intermediate differential number Respond faster to friction Create sharper and more angular motion Work well for speed-dominant players Offer many layout options because the PSA is stronger The added intermediate differential gives more shape and more ways to adjustthe core’s position during drilling How Intermediate Differential Affects Spin Time and PSA Strength Intermediate differential controls the strength of the PSA. A higherintermediate differential creates a stronger PSA. A stronger PSA means fasterspin time. Faster spin time leads to a quicker hook. Here is the simple chain: Higher intermediate differential → stronger PSA → faster spin time → quickerhook This is why high intermediate differential balls snap harder off the spot.They release energy quickly and make a fast move toward the pocket. Lower intermediate differential balls spin slower and transition moregradually. This helps the ball keep energy. Which Bowlers Benefit From Higher Intermediate Differential? A higher intermediate differential gives faster motion. This helps thefollowing players: Speed-dominant bowlers who struggle to get the ball to slow downLow-rev bowlers who need help creating motionPlayers who want strong backend shapeBowlers on patterns with a clear downlane friction spot Speed-dominant bowlers who struggle to get the ball to slow down Low-rev bowlers who need help creating motion Players who want strong backend shape Bowlers on patterns with a clear downlane friction spot These bowlers need help forcing the ball to change direction. A higherintermediate differential makes the motion sharper. Which Bowlers Benefit From Lower Intermediate Differential? Lower intermediate differential gives a smoother and longer motion. Thishelps: Rev-dominant bowlers who already create strong hookLow-speed bowlers who do not want the ball to overreactSenior bowlers who prefer short-pin layouts or smoother shapesBowlers on wet-dry patterns who want to control the breakpointPlayers who need stable and predictable motion Rev-dominant bowlers who already create strong hook Low-speed bowlers who do not want the ball to overreact Senior bowlers who prefer short-pin layouts or smoother shapes Bowlers on wet-dry patterns who want to control the breakpoint Players who need stable and predictable motion Intermediate Differential and Oil Patterns Intermediate differential plays a big role on different oil patterns. When to use high intermediate differential A high intermediate differential delivers a sharper transition at thebreakpoint. It’s great for rev-dominant players or anyone trying to get morehook on heavy oil. The higher diff gives the ball more flare and shape,creating that sharp, more angular motion through the backend. When to use low intermediate differential Choose a low intermediate differential bowling ball if you’re looking for asmoother, more predictable reaction. It’s perfect when the lanes start to dryup, or when you don’t want the ball snapping too hard off the spot. It givesyou that nice arc shape and better control through transition. Intermediate Differential and Drilling Layouts Asymmetrical bowling balls allow more layout options because the PSA plays akey role. Moving the PSA changes how the ball responds to friction. A higher intermediate differential gives more layout freedom. You can placethe core in strong or mild positions. A lower intermediate differential creates fewer differences between layouts.The ball remains smoother and more stable. Short-pin layouts reduce core flare. This makes the ball act closer to asymmetrical shape. Many senior bowlers use these layouts for added control. Examples of Bowling Balls With Different Intermediate Differential Values To understand these numbers better, here are clear examples of balls with high and low intermediate differential values. High intermediate differential examples Hammer Pure EnvyEbonite The One Ovation Hammer Pure Envy Ebonite The One Ovation These balls create sharp and fast backend motion. Low intermediate differential examples Storm Ion Pro SolidHammer 3-D Offset Assault Storm Ion Pro Solid Hammer 3-D Offset Assault These balls create smooth and continuous motion. No intermediate differential (symmetrical balls) Brunswick AlertMotiv Primal Ghost Brunswick Alert Motiv Primal Ghost These balls offer stable and predictable motion on many conditions.Please note that some links in this article are affiliate links, whichmeans we may earn a small commission that helps support our work, at noextra cost to you. Please note that some links in this article are affiliate links, whichmeans we may earn a small commission that helps support our work, at noextra cost to you. FAQ What is intermediate differential in bowling? Intermediate differential in bowling is the difference between the ball’s highRGaxis and its intermediateRGaxis. It shows how much asymmetry the core has and how fast the ball respondsto friction. RG Do symmetric bowling balls have intermediate differential? Symmetrical bowling balls have almost no intermediate differential. Theirvalues sit between 0.000 and 0.007. This is not enough to create strongasymmetry. What does higher intermediate differential do? A higher intermediate differential creates a sharper and faster motion. Theball responds quickly to friction and changes direction fast. What does lower intermediate differential do? Lower intermediate differential gives a smoother and more controlled motion.The ball changes direction slowly and keeps more energy for the pins. How does intermediate differential differ from differential? Differential shows the total flare potential. Intermediate differential showshow fast the hook shape forms. One controls the amount of hook. The othercontrols the shape of hook. Is intermediate differential important for beginners? Beginners do not need to worry about intermediate differential. Coverstock andtotal differential are more important at early levels. Which bowlers should use high intermediate differential? High intermediate differential helps speed-dominant and low-rev players. Italso helps bowlers who need strong recovery on the backend. Which bowlers should use low intermediate differential? Low intermediate differential helps rev-dominant and low-speed players. Itgives predictable and continuous motion on many patterns. How does intermediate differential affect drilling layouts? Higher intermediate differential creates more layout options because the PSAis stronger. Lower intermediate differential reduces the impact of layoutchanges. What intermediate differential value is considered high? A value above 0.021 is considered high. Values between 0.008 and 0.020 arelow. Values below 0.007 belong to symmetrical balls. Ready to choose the right equipment? Read our full guide to the BestBowling Balls in 2025!