If you're like most people, when you threw a disc golf disc for the first time, it went almost nowhere before diving hard into the ground. Quickly, you realized this simple fact: Very few disc golf discs fly like Frisbees.
This is because a Frisbee usually just needs to fly in whatever direction you throw it before someone with soft, breakable human hands catches it. Disc golf discs, though, need to weave around obstacles and their rims can be harder and sharper since no one is going to catch them.
That weaving is caused by factors disc golfers call "turn" and "fade," and the amount that discs turn and fade determines their stability. There are three broad categories for disc stability: Understable, stable, and overstable.
Learn all about disc golf stability by reading everything below or click/tap the topic you're most interested in to jump to it:
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- BASICS: What does stability mean in disc golf?
- BACKHAND & FOREHAND: What they are and how they relate to stability
- STABLE VS. OVERSTABLE: Are they the same thing?
- WHY are discs overstable or understable?
-PHYSICS of disc stability (gyroscopic precession)
-RIMS and stability
-PARTING LINE and stability
-Why are OLDER OR BEAT-IN DISCS MORE UNDERSTABLE?
-WIND and stability
-THROWING SPEED and stability
-DISC WEIGHT and stability
-How can DISCS OF THE SAME MOLD HAVE DIFFERENT STABILITIES? - A SYSTEM that helps identify understable, stable and overstable discs
-UNDERSTABLE DISCS: How to spot them, when to use them
-STABLE DISCS: How to spot them, when to use them
-OVERSTABLE DISCS: How to spot them, when to use them
Overstable, Stable, & Understable in Disc Golf: The Basics
Here are what overstable, stable, and understable mean in disc golf when discs are thrown flat and backhand by a right-handed player:
- Understable: A disc tends to go right and continue flying right until the end of its flight.
- Stable: A disc tends to stay straight throughout its flight, not moving far to the left or right.
- Overstable: A disc does not move far to the right before finishing to the left.
Here's a basic visual:
There are a couple of things we were careful to show in the photo above that might not be obvious:
- Notice where the hand is and how it's holding the disc: The disc is being held by a right-handed player using a backhand grip. This means the disc will spin clockwise once it's released. To see how this affects the meanings of understable and overstable, check out the next section of this post.
- The disc's angle is flat: It's only correct to say things like "stable discs go straight" or "understable discs go right" when you're talking about a disc released flat out of the hand (referring, again, to right-handed backhand throws). Using other release angles (called hyzer and anhyzer in disc golf), players can make stable discs go left or right and understable discs go left or straight.
How Do Backhand & Forehand Change A Disc's Stability?
The two primary ways people throw disc golf discs are backhands and forehands. Neither type of throw is guaranteed to make a disc more over- or understable for every disc golfer.
The style of throw and which hand throws it do change the directions of discs' spin, though, and that changes what overstable and understable mean:
- Right-handed backhand (RHBH), left-handed forehand (LHFH)
-Overstable means LEFT
-Understable means RIGHT
-Clockwise spin - Left-handed backhand (LHBH), right-handed forehand (RHFH)
-Overstable means RIGHT
-Understable mean LEFT
-Counterclockwise spin
Another way to think about these ideas is that discs always spin in the same direction as the side of the disc you're holding. Hold the disc on the right, for example, and the disc will spin to the right (or clockwise) after release.
When discs travel the same direction as they spin and continue going in that direction throughout their flight, they are understable. When discs tend to travel fairly far in the opposite direction of their spin, they are overstable.
Do Stable & Overstable Mean the Same Thing in Disc Golf?
Though the majority of disc golfers use stable and overstable interchangeably, the two terms technically have very different meanings:
- Stable: When a disc holds the angle of release throughout its flight when thrown at the proper speed
- Overstable: When a disc tends to fade fairly hard in the opposite direction of where the disc was gripped (a disc gripped on the right side – RHBH or LHFH – would go left, for instance). This doesn't mean a disc will never travel in the same direction as the side it was gripped on, but it will almost certainly not end its flight in that direction.
Plenty of disc golfers at every level of the game know this difference in theory but still commonly say "stable" to mean "overstable" or "stability" to mean "overstability."
For a quick example, notice how one commentator in the video below – a longtime touring pro named Paul Ulibarri – says, "This disc has stability" when what he truly means is not "This disc will continue traveling in the same direction it started in" but "Though this disc started its flight turned to the right, it will fade back left and avoid the out of bounds road to the right":
The same way you likely wouldn't blink an eye hearing a sentence like "You and me are going out to play today" where – say it with us fellow grammar nerds – "me" should be "I," hearing "stable" switched out for "overstable" is an error that's become so normalized that only real sticklers typically bother pointing it out. Unless you're genuinely unsure how someone is using the word "stable," it's best to go with the flow.
That said, we do keep to the actual definitions of these words in this post, so when you see "stable" here, we mean that a disc holds the release angle.
It's also noteworthy that since "stable" is often used to mean "overstable," many disc golfers use "straight" or "straight-flying" to describe discs that hold the lines they're thrown on.
What Makes Discs More or Less Stable?
Many factors make a disc more understable or overstable, and you can learn about the most important ones by clicking or tapping on them below:
- Gyroscopic precession
- Rim width and height
- Parting line location
- Amount of use (i.e., how "beat-in" they are)
- Wind direction
- How fast you throw it
- Disc weight
- The difficulty of recreating perfectly identical discs
The Physics of Disc Golf Disc Stability (Gyroscopic Precession)
Perhaps the most important and least generally understood factor in disc golf discs' stability is a phenomenon called "gyroscopic precession."
Here's a very basic explanation of how gyroscopic precession works and affects discs:
- When a circular object is traveling through the air with spin, a force applied to the object's front (the point farthest forward in the direction of travel) will actually affect a point 90 degrees from the front in the direction of spin.
- In disc language, that means if a disc is spinning, for example, to the right (clockwise), and air pushes down on the disc's front (or "nose"), the right wing of the disc will go down and force the left wing up.
- When the nose of the disc is pushed down, the disc turns (i.e., moves in the direction of understability). When the nose is pushed up, the disc fades (i.e., moves in the direction of overstability).
The most important thing to take away from this very quick physics lesson is this:
- Nose down = more understable
- Nose up = more overstable
Of course, discs' shapes impact how and where air passes over them, making them more and less prone to acting under- and overstable. We cover those ideas in the next sections.
For anyone interested in a deeper dive into (or just more visualizations of) gyroscopic precession's effects on discs, there's a video that features a cool gadget and easy-to-follow visuals.
Just note that the host prefers to say he's applying pressure to the back of the disc instead of the nose – this is the opposite of our visuals where we show air affecting the disc's nose and what happens as a result. We think our example is a little easier to follow, but, in the end, we're making the same points and just describing them in different ways:
How Rims Affect Disc Golf Discs' Stability
How a disc's rim (outer edge) is constructed changes a lot about how a disc flies and what sorts of throws make it act over- or understable. Generally, as you move up the tiers of discs from putters to midranges to drivers, you should expect ever lower profiles and wider rims.
Here's what this means for most putters and midranges:
- Thinner rims mean lighter rims, and rims (where we always grip a disc) that are lighter take less power to spin at the correct speed.
- Because it takes less energy to get the disc spinning at the right rate, the differences between spin rates at the start and end of flights are usually less extreme than with drivers, resulting in less potential for extreme fade (i.e., extreme overstability at end of flight).
- Higher profiles mean more drag (exposure to air pushing in the opposite direction of flight) and less potential distance, but...
- ...those whose throws are less powerful may still throw putters and midranges farther than drivers because they are able to release them with the right spin rates, avoid extreme overstability, and achieve full flights.
Here's what it means for most drivers:
- Wider rims mean heavier rims, and heavier rims take more power to spin at the correct speed (and creating that power takes good throwing form).
- If a wide-rimmed disc...
-...gets spun at the right speed, it will continue spinning and therefore (given that the throw height is right) continue flying for longer than a putter or midrange thrown at the same speed.
-...does not get spun at the correct speed, it will act very overstable, fading to the ground very soon after release. - Wide-rimmed discs tend to have more extreme differences between spin rates at the start and end of their flights, making them more likely to fade hard (act overstable) at the end of their flights.
- Lower profiles mean less drag and more potential distance, but...
- ...those with less power are unlikely to release drivers with high enough spin rates to avoid extreme overstability and achieve that potential distance.
How Disc Golf Discs' Parting Lines Affect Stability
When comparing two of the same or similar discs, the disc golf disc with the lower parting line will be more understable and the one with the higher parting line will be more overstable.
A parting line is a remnant of the injection molding process used to make discs. Multi-part molds are pressed together in injection molding machines, filled with hot plastic, and then pressed together with even more pressure to assure the injected plastic spreads to the right densities in the right places. Once the plastic is correctly spread throughout the disc mold, the plastic cools down, the mold's parts pull apart, and the newly-made disc can be taken out.
The parting line is where two parts of the mold met and left a tiny crack that a very thin ring of plastic crept into:
The reasons parting lines relate to disc golf disc stability take us back to the concept of gyroscopic precession we talked about earlier:
- When a disc has a lower parting line, more air passes over the disc than under it when traveling at high speed. This puts downward pressure on the disc's nose. Through gyroscopic precession, that pressure then pushes down a wing 90 degrees from the nose in the direction of spin that makes the disc take a more understable flight path.
- When a disc has a higher parting line, more air passes under the disc than over it. This puts upward pressure on the disc's nose. Through gyroscopic precession, that pressure then lifts a wing 90 degrees from the nose in the direction of spin that makes the disc take a more overstable flight path.
Of course, these effects can be manipulated by forcing the nose of a disc down or up at the point of release. For example, no matter where a parting line is, if a disc is released with its nose tilted very high (and especially at a slow speed), more air will pass under it than over it, making the disc fly with an overstable flight pattern.
Similarly, If you release a disc with a high parting line with a nose down angle and enough speed and spin, it will turn in the direction an understable disc would for a while before finishing in an overstable direction as it loses speed and the nose tilts upward again.
Why Are Older or Beat-In Disc Golf Discs More Understable?
As discs get used, they get banged up by their edges hitting the ground, trees, and other objects with lots of force. Over time, that pushes their edges lower which, in turn, makes their parting lines lower. And as we learned above, the lower a parting line is, the more understable a disc becomes.
Most disc golf disc brands' least-expensive or "baseline" plastics are also the most quickly affected by these impacts. Hit a couple of trees hard with a baseline plastic disc, and you're likely to see some deep gashes and big changes to its shape. More premium plastics can take much more punishment and continue to hold close to their original shapes.
This is why it takes longer for premium plastic discs to "beat in" (i.e., become slightly more understable with use). It's also why experienced disc golfers often fear losing certain premium plastic discs that they've spent years beating in to their ideal level of understability.
See this phenomenon explained in a short clip from a video by Best Disc Golf Discs:
How Wind Affects Disc Golf Disc Stability
When talking about stability, disc golfers tend to focus on headwind (wind blowing in the opposite direction that your disc is traveling) and tailwind (wind blowing in the same direction your disc is traveling).
Here's how headwinds and tailwinds affect disc stability:
- Headwinds make discs fly in more understable patterns.
- Tailwinds make discs fly in more overstable patterns.
There are two big reasons for these effects.
One of them is that headwinds make the air speed of discs faster and tailwinds make their air speeds slower, and discs moving at higher air speeds are more prone to being understable (or turning) and discs moving more at slower air speeds are more prone to being overstable. If you'd like to dive deeper into the "why" behind this, check out the section on disc golf disc flight numbers and wind in our post "Disc Golf Disc Numbers: What They Mean (And What They Don't)."
The other is our by now familiar friend gyroscopic precession. Headwinds apply more force to discs' noses than their tails, and due to gyroscopic precession, that forces down the wing that makes discs turn and be more understable. Tailwinds apply more pressure to discs' tails than their noses, and gyroscopic precession then moves that downward pressure 90 degrees in the direction of spin to force down the wing that creates fade and overstability.
How Throwing Speed Affects Disc Golf Disc Stability
For this one, we're keeping it really simple:
- The faster you throw a disc, the more understable it will fly.
- The slower you throw a disc, the more overstable it will fly.
Don't forget, though, that physical factors of a disc like rim width and parting line location matter a lot to how over- and understable it is. Release angles, nose angles, and wind direction matter, too.
How Disc Weight Affects Disc Golf Disc Stability
The weight of discs matters to stability mostly because of how hard or easy that weight makes it to throw a disc at a high speed.
Imagine two of the same type of disc, but one is 160 grams and the other is 170 grams. If you wanted to release them both at the exact same speed, it would take less force to release the lighter disc at the same speed as you release the heavier disc.
To think about this idea in an exaggerated way, consider taking the force that makes your everyday four-door car go 60 miles per hour/97 kilometers per hour and using that same amount of force to propel a tank. The tank won't go anywhere near the speed of the car.
Since – as we learned in the last section – discs act more understable the faster you throw them, many disc golfers believe that lighter discs are more understable and heavier discs are more overstable. The better way to say that, though, is that it's easier to make lighter discs fly in understable patterns than heavier discs because lighter discs are easier to throw at higher speeds.
Why Do Disc Golf Discs of the Same Mold Have Different Stabilities?
There are many reasons discs of the same mold might fly with more over- or understability (or appear to), but the two biggest are these: Weight and height of the parting line. These are both topics we've covered above, so we'll be brief about them here.
If you have two of the exact same discs, but one is lighter and the other is heavier, the lighter one will likely appear to be more understable because it takes less force to throw it at a high speed. Higher release speeds mean discs will fly with more understability.
As for parting line height (lower parting lines mean understability and higher parting lines mean overstability), that can differ even for the exact same type of disc in the exact same weight and plastic. Why? Every disc has to be individually molded, and that means each one will set in its mold in different ways. These differences are often very slight, but even slight changes in a disc's shape can affect how it interacts with the air, making it more or less under- or overstable.
For a testimonial from the owner of a disc-making enterprise about the difficulty of making consistent discs, just watch this clip of eco-friendly disc golf company Trash Panda's Jesse Stedman:
Understable, Stable, & Overstable Disc Golf Discs: How To Identify Them, When To Use Them
Throwing a disc a few times in neutral wind conditions is the best way to know how over- or understable it will be for you. But if you can't throw a disc before you buy it, the best thing to do is check its flight numbers. This a system with four numbers that are usually shown in a straight line and mean, respectively, from left to right:
- Speed (1 to 14): The higher the number, the faster a disc should cut through the wind/air and the faster you need to throw it for it to achieve its intended flight pattern.
- Glide (1 to 7): The higher the number, the longer a disc should potentially stay in the air.
- Turn (-5 to 1): The lower the number, the more likely a disc should be to turn (i.e., fly in the direction meant by "understable") when traveling quickly.
- Fade (0 to 5): The higher the number, the more likely a disc should be to fade (i.e., fly in the direction meant by "overstable") when traveling at slow speeds.
Turn and Fade matter most when you're discussing stability. If a disc does not have flight numbers printed on it, most online retailers list them.
Learn how to use these numbers to identify discs of different stabilities and when those discs are most useful:
Understable Disc Golf Discs
Understable disc golf discs tend to turn in the direction they're spinning and either continue traveling in that direction their entire flights or fade only slightly in the opposite direction as they slow down near the ends of their flights.
An understable disc thrown backhand by a right-handed player will spin right and turn right, for example. But here's a visual of what understable means in terms of all common throws:
Understable discs' flight numbers usually meet these two criteria:
- High turn
Weirdly, "high" turn is actually a low number. Turn is rated on a -5 to 1 scale, and the lower a number is, the more a disc should turn – with -5 representing max turn. For most players, discs with turns of -5 to -3 (or even -2 in some cases) would be considered high turn. - Low fade
In this case, "low" means low. Rated on a 0 to 5 scale, understable discs usually have fades of 0 or 1.
Keep in mind, though, that disc speed (putters are low speed and drivers are high speed) also plays a factor here. Check out the section on rims above to learn more about why.
Top reasons for having understable disc golf discs include:
- You're a player with less power seeking distance.
The less power you have, the more understable your discs for distance should be. Though you may not see too much of the turn, the low fade of understable discs means they should progress down the fairway before fading to the ground. - You throw solely forehand or solely backhand.
If your game is based mostly around one type of throw, you'll need some understable discs that can flip up to and hold anhyzer angles throughout their flights. - Tailwind
Tailwinds make discs fly in more overstable patterns. The stronger the tailwind, the more your disc's overstability will be amped up. That means your trusty driver that turns and fades perfectly in normal conditions might not turn at all before fading hard when you throw it with tailwind – and you'll need something more understable to recreate your ideal flight pattern. - Anhyzers
Even if you're comfortable with forehands and backhands, some holes have lines where flip-up shots or anhyzers are just the better fit. You might also end up in an off-faiway position where your line or surroundings limit you only to an anhyzer angle that a disc needs to hold. - Rollers
Though some power players can roll just about any disc, most players who throw rollers use understable discs.
Stable Disc Golf Discs
First, remember that we're talking here about the actual meaning of "stable," which is that a disc tends to hold the angle it's released on throughout its flight without significantly turning or fading.
No matter if you throw with your left or right hand, with a forehand or a backhand, a stable disc should simply hold the line you release it on. A flat release should mean a straight shot, a disc tilted to the right should travel to the right, etc.
Stable discs' flight numbers usually meet these three criteria:
- Little turn
Turn is expressed on a scale from -5 to 1, with -5 being the highest turn and 1 being the lowest. Stable discs tend to have turn ratings ranging from -1 to 1. - Little fade
Fade is expressed on a scale from 0 to 5, with 0 representing minimum fade and 5 representing maximum fade. Stable discs tend to have fade ratings of 0 or 1. - Not high speed
The wider rims of distance drivers make it physically unlikely that they will fly without turn or fade. Some players have fairway drivers they'd consider stable, but most famously stable discs (e.g., the Innova Mako3 or MVP Glitch) are midranges and putters.
Top reasons for having stable disc golf discs include:
- You want a disc that flies like a Frisbee.
If you're coming to disc golf from a different disc sport or with lots of experience throwing Frisbees for fun, the flight patterns of stable discs will be the most understandable at first. That's because high quality Frisbees generally follow stable flight paths. - Straight shots
Some say that the hardest flight pattern to throw in disc golf is simply straight, and plenty of course designers love testing that theory with straight tunnel fairways. While some players like releasing understable discs with hyzer so that they flip up to fly straight, others prefer to release stable discs flat and (hopefully) watch them hold that angle all the way down straight fairways. - Controlling angles
Since stable discs hold the angles they're released on, they're perfect for players who either already have lots of control over their release angles or want to learn to have it. For example, you might have a fairway that calls for an anhyzer throw, but you're worried about how easily you might overturn an understable disc. A stable disc can also hold an anhyzer and lessen the possibility of too much turn.
Overstable Disc Golf Discs
Overstable disc golf discs tend not to turn very much (if at all) and fade hard in the opposite direction of their spins as their air speed slows.
An overstable disc thrown backhand by a right-handed player will spin right (clockwise) but fade left fairly soon, for example. Here's a visual of what overstable means in terms of all common throws:
Overstable discs' flight numbers usually meet these two criteria:
- Low turn
Turn is expressed on a scale from -5 to 1, with -5 being the highest turn and 1 being the lowest. Overstable discs tend to have turn ratings ranging from -1 to 1. - High fade
Fade is expressed on a scale from 0 to 5, with 0 representing minimum fade and 5 representing maximum fade. Overstable discs tend to have fades of at least 2 and, more often, 3 or more.
Top reasons for having overstable disc golf discs include:
- Predictability
Whether you're a powerful player who needs a distance disc that won't just turn and keep turning or any who sometimes needs to be sure a disc will finish in a certain direction (maybe to miss a lake or other out-of-bounds area), overstable discs will be more reliable for these jobs than understable discs. - Headwinds
Headwinds make discs fly in more understable patterns. The stronger a headwind is, the more extremely a disc is likely to turn. This means your typically straight-flying midrange could suddenly be transformed into a roller disc by a strong headwind, and you'll need to throw a more overstable disc to achieve that straight line you're hoping for. - Flex shots
Sometimes holes call for a disc to travel two different directions to follow their intended fairways. When they do, you might want to throw a flex shot to achieve it. A flex shot is when you intentionally throw an overstable disc on an anhyzer angle so that it turns more in the direction of its spin than it typically would before fading out in the opposite direction:
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