Day #244: Aug. 31st, 2026
How Scoring Differs on String vs. Free-Fall Pinsetters
Bowling uses the same basic scoring system whether a center uses string pinsetters or traditional free-fall machines. A strike is still worth 10 pins plus the next two shots, a spare is worth 10 pins plus the next shot, and an open frame is scored by the number of pins knocked down. The main difference is how the pinsetter determines whether a pin has fallen.
What Is a Free-Fall Pinsetter?
A traditional free-fall pinsetter allows the pins to stand freely on the lane. After each delivery, the machine sweeps away fallen pins, resets standing pins, and places new pins on the deck.
With free-fall equipment:
- A pin is counted as down if it has fallen and the pinsetter does not touch it.
- If the machine touches a pin during the reset cycle, that pin is considered standing.
- A standing pin is normally picked up and returned to its original position.
- A pin that is leaning or wobbling may remain in play until the machine completes its cycle.
This system has been used in most competitive bowling for decades, so bowlers are familiar with how pins react and how close calls are handled.
What Is a String Pinsetter?
In string bowling, each pin is attached to a string. Instead of using a mechanical table to pick up and reset the pins, the machine pulls the strings upward to clear fallen pins and return standing pins to the deck.
String pinsetters generally determine pin status by detecting the movement of the string:
- If the string moves beyond a programmed distance, the machine registers the pin as fallen.
- If the string does not move far enough, the pin is treated as standing.
- A pin that is tilting may be ruled down or standing by the automatic scoring system.
- Standing pins are re-spotted before the next delivery.
- A pin that is still standing on the deck remains standing for scoring purposes.
This means bowlers may not always be able to judge a leaning pin simply by watching it. On a string machine, the scoring system determines the final result.
Close Pinfalls Can Be Different
The biggest difference occurs when a pin is moving, leaning, or affected by other pins and strings.
On a free-fall machine, the pinsetter’s contact can help determine whether a pin is counted as standing or down. On a string machine, the system relies on string movement and its scoring sensors. As a result, the same ball motion may occasionally produce a different pinfall result on the two systems.
A pin that appears to be falling may be reset as standing on a string machine. In another situation, a string may help pull a pin out of the way or influence how surrounding pins finish their movement. The final score is based on the machine’s approved scoring determination, not only on what the bowler sees.
Do String Pinsetters Produce Lower Scores?
Early USBC testing suggested that string pinsetters could produce lower strike percentages and average scores than free-fall machines. Preliminary research estimated that string-machine strike percentages might be about 7.1% lower, potentially creating average differences of 10 pins or more in some situations.
However, USBC later conducted controlled research on certified string pinsetters and concluded that there was no statistically significant difference in scoring pace compared with traditional free-fall machines. USBC stated that average conversions would not be necessary when the string pinsetter is properly certified.
The important distinction is that not all string machines are identical. Results can vary because of the machine model, string length, lane conditions, kickbacks, pin specifications, oil pattern, and scoring settings.
Competition and Average Rules
For USBC-sanctioned competition, the string pinsetter must meet the organization’s certification requirements. USBC’s current position is that averages from certified string pinsetters and free-fall machines may be interchangeable without an automatic adjustment.
That does not mean every bowler will experience the same scores on both systems. A bowler’s strike percentage, spare conversion rate, ball reaction, and comfort with the pinsetter can still change. It means that certified equipment is considered sufficiently comparable for official average purposes.
Before entering a league or tournament, bowlers should check:
- Whether the center uses USBC-certified string pinsetters.
- Whether the league or event recognizes scores from that equipment.
- How tournament standings and handicap averages are calculated.
- How the center handles questionable or incorrectly recorded pinfall.
Whether the automatic scoring system has been tested and properly configured.
How Bowlers Should Adjust
The biggest adjustment is mental: trust the official result shown by the scoring system. A leaning pin may look like it should fall, but the machine’s determination controls the delivery unless the center’s rules allow a correction.
Bowlers can also expect a slightly different visual rhythm. String machines often reset more quickly and may create different pin movement during deflection shots. Instead of assuming that every free-fall reaction will repeat exactly, pay attention to:
- How light hits finish.
- Whether pins deflect differently off the headpin.
- How often corner pins remain standing.
- Whether strings affect the appearance of late pin movement.
- How the lane surface and backend shape influence pin action.
The best approach is to watch the first several frames, identify the common leaves, and make normal lane-play adjustments rather than changing equipment immediately.
The Bottom Line
String and free-fall bowling use the same scoring rules, but they determine pinfall through different mechanical systems. Free-fall machines rely on the interaction between fallen pins and the pinsetter, while string machines use string movement and automated detection to classify pins as standing or down.
For certified string pinsetters, USBC research indicates that no average conversion is required. Even so, bowlers may notice differences in close pinfalls, pin action, strike frequency, or spare leaves. Understanding how the equipment scores each delivery will make it easier to adapt and keep the focus on making good shots.