On the last day of this year’s golf ball test, we had a little bit of extra time to run a few smaller experiments. Near the top of our list was mud balls. We wanted to find out what happens, or at least what you should expect to happen, when mud finds its way onto your golf ball.

It also seemed like the perfect opportunity to try and answer another question we get asked all the time: Does cover damage, whether that’s from the cart path, a crisp bunker shot, a tree or anything else that leaves a mark, impact the performance of the golf ball?

The original plan was for two separate articles but it turns out that the severity of the real-world implications is driven by the extent of the damage or disruption. In general, whether it’s mud on the cover or some sort of other disruption or damage to the cover, the resulting ball flight is basically the same. Not good, but the same.

So, with that said, let’s look at what we found.

Key Takeaways

It doesn’t take much damage to have an impact

It turns out that even the kind of thing most of us would overlook can cause performance issues. Anything that alters the prescribed shape and depth of the dimples, whether that comes from filling them with mud or scraping bits of them away with a crisp wedge shot out of a bunker (or a not-so-crisp drive that hits a cart path or tree), can be problematic. When you mess with the golf ball’s aerodynamic structures (dimples), bad things can, and often will, happen.

The bigger the damage, the bigger the impact

It should go without saying but the more significant damage, the bigger affect it’s going to have on performance.

Small paint blemishes and even very minor surface scratches are likely no big deal but if the damage is easily felt—if there’s a tactile experience—it will very likely have an impact on performance. A little bit of damage (or a little bit of mud) can cause your ball to fly a little bit offline or a little bit shorter. A bit more damage and you should expect to find yourself screaming “Fore left (or right)!”

The ball will move in the opposite direction of the mud or scrape

I’ve taken to using the word “disruption” as a kind of a catch-all for just about anything that buggers up the surface continuity of a golf ball. What’s important to know is that, regardless of whether that disruption is mud or a scrape, gouge or cut, the ball can be expected to move in the opposite direction of the damage.

If there’s mud on the right side of the ball, it’s going to curve to the left. If you’ve got a scrape on the left side of your ball, it’s going to cause the ball to move to the right. Adjust your aim accordingly and hope for the best.

When in doubt, throw it out

If there’s one overarching takeaway, it’s that you need to know when to say goodbye to your golf ball. The Rules of Golf leave little recourse for mud balls but you have near-absolute freedom to remove a damaged ball from play. We know it sucks to have to trash a $4 golf ball because of cover damage but you should be able to appreciate that there’s an inevitability to it. The probability is a damaged ball will eventually fly OB so you might as well trash it before it costs you strokes.

Mud balls

To test the impact of mud on the golf ball, we made our best effort to replicate the amount of mud that might realistically find its way onto your golf ball from landing and rolling on a wet and perhaps not perfectly manicured fairway.

We tried to put enough mud on the ball to have a pronounced impact but we didn’t cake it on, pack it tight or otherwise try to fill every dimple with soil.

Shots were hit using a mid-speed  8-iron (100-mph driver equivalent) in a configuration identical to that of the primary ball test.

Mud Ball Data


  • It’s worth restating what is perhaps the most significant takeaway from this experiment: the ball will move in the opposite direction of the mud (or any other surface disruption).
  • The majority of the mud flies off at impact. This doesn’t prevent the ball from tilting but it does reduce downrange aerodynamic implications.
  • Key metrics like ball speed, launch angle and spin were only marginally impacted by the presence of mud outside of the impact area.
  • The consequence of mud is most apparent in the spin axis number. The greater the axis tilt, the more the ball typically curves during flight. It’s worth noting that, in robot testing, spin axis numbers are typically +/- 1°.
  • Mud on the left side of the ball (the scenario in which we had the most mud on the ball) caused the spin axis to tilt nearly 6 1/2 degrees to the left and the ball to fly seven yards offline (to the right).
  • With less mud on the ball, we saw similar, though not as severe, results with mud on the right side of the ball.
  • In our test, we didn’t see much of a distance loss due to mud. However, we surmise that not all mud is created equal. The stickier the mud, i.e., the more it clings to the surface of the ball post-impact, the greater the influence it will have on ball flight.

Scuffs, scrapes and other disasters

To test the impact of scuffs and scrapes on ball flight, we attempted to recreate the various degrees of cover damage that result from things like hitting the cart path or a tree or a crisp bunker shot. As we saw the results of our first couple of shots, we decided to get extremely aggressive—in some cases beyond what’s directly applicable to your round of golf (we hope)—but, nevertheless, the results are interesting.

For this test, we used a driver at 100 mph. The configuration was designed to closely mirror the setup from our primary ball test. Note: for all shots, unless otherwise noted, the damaged area was aligned to the right side of the impact area.


Light Scuff

a photo of a golf ball with a minor scuff or scrape

  • Even with what amounts to a small but noticeable scrape—the kind of thing you often find after bouncing one off the cart path—there was a noticeable impact on ball flight
  • Our lightly scuffed ball had a pronounced, though not massive, shift in the spin axis, resulting in a shot that flew more than eight yards off line.
  • Peak height was well below the average for an unscuffed ball, though a significantly flatter descent angle contributed to a massive amount of roll.

Moderate Scuff

  • With a moderate scuff—the kind of thing we think many golfers would likely replace—we saw a significant impact on ball flight.
  • While ball speed, launch angle and spin rates weren’t far off from the unscuffed averages, the ball flew nearly 30 feet lower.
  • Carry distance fell to 205. That’s more than 40 yards less than the average of undamaged balls.
  • The spin axis tilted by more than 35 degrees, resulting in a shot that finished more than 45 yards off the target line.

Balanced Scuff

  • While the damage isn’t likely to mirror anything you’ll experience on the golf course, we were curious to see what would happen when we moderately and evenly scuffed both sides of the golf ball.
  • Scuffing both sides of the ball created a higher spin rate.
  • The spin axis tilted a bit more than 4.5 degrees and the ball flew almost 13 yards offline. If nothing else, this suggests our scuffs were not perfectly balanced.
  • Peak height was less than 50 feet and the descent angle was only 23 degrees.
  • The total distance was less than 250 yards (only 200 yards carry) and, while it doesn’t come through in the data, the ball flight was erratic. Unstable is perhaps a good description.

Partially Sanded

  • As a curiosity, we sanded off approximately one-quarter of the dimples on a ball. While again we don’t expect you’ll experience this type of damage on the golf course, it is a reasonable representation of what you might encounter while hitting your way through a bucket of old range balls.
  • The spin axis of the partially sanded ball was nearly 50 degrees, resulting in a ball that finished almost 57 yards offline. Basically, the ball duck-hooked.
  • Carry distance dipped less than 200 yards.
  • Peak height was well below what we’d expect from an undamaged ball.

Core Only

  • Admittedly, this one was just for fun, though I suppose I could tell you it was to see how a ball flies without any aerodynamic features (dimples). The results were, nevertheless, interesting.
  • With no cover or mantle layer, ball speed actually increased by 4.5 mph.
  • Without dimples, however, launch angle was only 10 degrees and the peak height was less than 20 feet—with a driver!
  • The ball carried just a bit more than 115 yards. I’m guessing that’s wedge distance for many of you.
  • If there’s an upside, it’s that the cover-less ball flew relatively straight, finishing three yards off the target line.

The takeaway

If you take one thing away from this article, it should be that any disruption on the surface of the golf ball, whether that’s mud or a scuff, has the potential to affect the flight of the golf ball.

Unfortunately, there’s nothing you can do about mud on your ball but the good news is that its impact is predictable. Whether it’s mud or a scuff, the ball will predictably curve in the direction opposite the disruption. For a bit more detail, we highly recommend this PING Proving Grounds article on The Science of Mud Balls.

If you’re trying to figure out if it’s time to replace your ball, a good rule of thumb is that if there’s enough damage that you can feel it when rubbing your finger over the ball, it’s probably best to toss it in the shag bag before it impacts your score.

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