Normal force, N, is the force that pushes up against an object, perpendicular to the surface the object is on. In other words, the normal force is the force pushing the two surfaces together. The stronger the normal force, the stronger the force due to friction.
How often have you experienced an oil pattern that didn’t play anything like the pattern graph suggested it would? The pattern was ‘x’ length, the high point of the oil on ‘y’ board, yet when you played on it your ball didn’t react anything like you expected, and the optimum pattern exit point wasn’t near where it was “supposed to be”.
From there we look for explanations, and we might get answers like; “the temperature was different today”, “it was raining outside”, “the lane machine put out the wrong pattern”, or who knows what else. In past years technology might not have been available to check things, so theories flourished.
Today, however, we can use technology to confirm the correct pattern is in the lane machine. We can use the Lane Monitor to make sure it was applied correctly to the lane. And with the Kegel LaneMapper, we can even measure the topography of the lanes to see if and how that influenced things.
Knowing and understanding these critical components about our invisible playing environment can help us answer the infamous question every person entrusted with lane conditions has heard at least once in their life; “what happened?”
What lane topographies are most common?
The Kegel Training Center has 12 fully adjustable lanes that can be shaped to mimic almost any lane topography known to exist. After measuring thousands of lanes over the years we have shaped three pairs of lanes in the KTC with some common topographical shapes, and one pair of lanes we consider as “fairly neutral”.
Neutral lanes are not perfectly flat, no lane in the world is, but a neutral lane has topographical slopes on them which do not “overly disturb” the ball as it travels from the foul line to pin deck.
We see neutral lanes often when they are made of wood and resurfaced regularly – these lane types are the “flattest” lanes with regard to topographical shape.
We also see neutral synthetic lanes, but not very often. In fact, of all the synthetic lane bowling centers we have mapped over the years we can count the number of centers having totally neutral synthetic lanes on one hand – it's definitely the exception, not the rule.
The three most common topographical shaped lanes today are what we call a seagull-wing or bird-wing shape, depressed (dish-shaped), and crowned (mound-shaped). These lane shapes are where things get interesting with regard to oil patterns, how they play, and maybe most important, how they develop as the oil pattern breaks down.
Seagull-wing shaped lanes have slopes towards the center from around the second arrow, and slopes towards the gutter outside of that. This happens because a synthetic panel is mostly screwed down on the outside 1st or 2nd boards on either side and then in the middle on the 20th board. In-between there are no securing screws “holding the panel down” other than where the panels meet, which is only every 10’ or 12’ depending on the manufacturer.
In the summertime when the humidity is high, or in climates with high humidity, we see this lane shape very often - especially when wood lanes are underneath the panels.
Moisture penetration on a wood lane comes from the bottom of the lane where the boards are put together essentially making the lane swell up, which then pushes up the panels in-between these rows of securing screws. This causes the lane to “mound up” around the 8-9-10 board creating slopes towards center inside of that area, and slopes towards the gutter outside of that. The resulting shape resembles a seagull's wing.
Furthermore, in both new lanes with a continuous LSL underlayment (Laminated Strand Lumber - an engineered wood product) and for certain manufacturers who use MDF or LSL to replace the old wood head section, there is a similar securing-screw pattern.
Just like the lane panels themselves, the underlayment is top-screwed in three spots across the lane, near the two outer edges and near the middle, at each of the 30 or so securing locations along the 60' length of the lane. This can also create a bird-wing shaped lane; albeit not as severe as what we see with a wood lane underlayment in high humid environments.
Crowned lanes also happen in year-round climates with high humidity; like Island countries, cities by the sea, or in Southeast Asia. This often happens with overlays where the wood lane underlayment was not screwed down in the middle prior to the lane panel installation.
Depressed lanes often happen in lower humidity climates, or in the winter time, with a wood lane underlayment. In fact, all wood lanes are cut with a slight depression in them, but the longer the panels have been on top of the old wood lane, the more they tend to depress - especially in the area of the lane that takes the constant pounding of the bowling ball, the first third of the lane.
Have you ever notice that scores often go up after Christmas time? This is when a wood lane, or synthetic panels on top of wood lanes, become most depressed because the moisture has finally been released from the wood causing it to contract (shrink). Think of a high banked race track - it's much easier to navigate the curve.
New synthetic lanes can also be installed with a depression, but rarely do we see a nice smooth depression like a resurfaced wood lane has.
Although we see these type lane shapes often down the entire lane, we also see at times a combination of shapes on any one lane. For certain type overlays, we often see very depressed heads and slightly beyond (mostly related to ball impacts), and then bird-wing shapes after that.
In the case of a new synthetic installation, we often see topography slopes that are totally random throughout any one lane, or even within one panel.
Lane shape is more the reason than anything else why certain styles (ball rolls) “match up” to certain bowling centers.
Because of the invention of the Kegel LaneMapper and resulting Slope Graphs, we now know why, and we can show it.
Where the rubber meets the road
A few months ago the Men’s National Team from Sweden came to the Kegel Training Center with a special request; to learn more about topography and train on lanes with topography differences. So to prepare for their visit we adjusted lanes 5-6 with a seagull-wing shape, lanes 7-8 with a crown, and lanes 9-10 with a depression. We also made sure the lanes remained within USBC specifications.
Below are the Slope Graphs of each pair of lanes:
Remember, the specification for lanes is plus/minus .040”, and it does not specify which way a lane must be shaped in order to satisfy those requirements. The specification also does not state over how many boards those min/max numbers can hit their limit, and that’s where things can get interesting.
For instance, if there is a .024” rise on the lane from the gutter to the eighth board, that’s an average Slope per Board of .003” – that equates to a smooth cross-tilt of .120”. The ball has a very hard time “hooking back to the pocket” on a slope this severe and we see this more often than you might think.
For more about Slope per Board, read this article: http://www.kegel.net/wpa/kegels-revolutionary-slope-graphs
So how does lane topography affect an oil pattern and the resulting breakdown?
This is where we have learned the same thing Sir Isaac Newton learned – you can’t fight gravity, you can only work with it.
For a little test and learning experience for all involved, we decided that the 12 players from Team Sweden would bowl six games across the three pair of lanes moving every game – this would make all players hit each pair twice.
There were three left-handed players and nine right-handed players. We chose a medium length oil pattern from the 2017 World Bowling patterns, Beijing.
Here is what the fresh oil pattern looked like, with the foul line being at the top of the graphic:
After 12 games of bowling, we took after tapes on each of the pairs to see how the players broke down the oil pattern on these different lane shapes.
On lanes 5-6, the bird-wing shaped lane, players tried to play outside in practice but the slopes towards the gutter made it play very difficult - they immediately “moved inside” and away from the “hang spot”.
The after tapes show the paths of all balls by way of oil pattern depletion. From these tapes, we can clearly see both left-handers and right-handers played deep inside on this pair of lanes. Our tape data also shows the farthest outside anyone got was on board 9, because there was hardly any pattern depletion of the pattern outside of that. Specto data confirmed this depletion observation.
On lanes 7-8, the crowned pair of lanes, everyone stayed much more outside and never migrated that deep - in fact, they never got inside the third arrow. A few factors involved here; gravity simply helps “push” the ball towards the outside, and the ball doesn’t see pattern breakdown near as much because it's rotating "with the slope" - Normal Force is lessened.
On lanes 9-10, the depressed shaped pair of lanes, the depletion data shows how quickly everyone moved inside and how far they banked it to the towards the outside part of the lane – there wasn't a "hang spot" on that lane.
From our experience we know the ball “sees breakdown" much quicker on the uphill side of a depressed lane because the lane is essentially pushing up against the ball (greater Normal Force) making it “poke through” the thin oil film easier, which causes more friction and makes the players move inside quicker.
Once deep inside and players can play the “downhill side” of the depression the oil pattern might even feel like it has “stabilized” when in fact, it’s just gravity helping the ball “push” towards the outside. In this case, we literally mean push.
This lane shape is the main reason lofting of the gutter comes into play. Along with the pattern "feeling" like it's breaking down quickly, by lofting the gutter cap the ball is able to remain on the downhill side of the depression longer. This allows the ball to retain more energy while also creating a bigger margin for error, along with improved pin carry.
If players tried to stay to the right towards or on the uphill side of the depression, the ball would simply use up energy too quick, minimizing both pin carry and mistake area.
Along with depletion data, we used Specto to track the ball paths on each lane. The below graph shows the average lines of each right-handed player during the last game; the blue line is the bird-wing shaped lane, the orange line on the crowned lane, and the grey line on the depressed lane.
Just like the depletion data showed, the players were most inside on the bird-wing shaped lanes in order to stay away from the hang area and to control the pocket. On the depressed lanes they had more “free hook” so they could swing the ball out farther. And on the crowned lanes, they didn't have to move deep inside so they stayed to the right much farther and played a tighter line.
So there we have it – the same oil pattern, applied at the same time with the same lane machine, using the same oil and cleaner, on the same lane surface, with the same bowlers, but three different lane shapes causing that oil pattern to play different, and break down significantly different.
Topography has been a buzz word for a few years now and we’re really seeing how influential it is, and how it affects lane play. For instance, want to know which part of the lane your ball is influenced by topography the most? Or how different ball rolls are affected by these slopes on the lane surface?
We’ve watched enough over the years to make some conclusions which are not only backed up by results but by physics. Stay tuned, the answers will be enlightening…