The truth about stability is that it is as confusing as the day is long. Unfortunately, when a disc is said to be ‘stable’, it could mean it goes straight the entire flight, not turning left or right when slowing down. It does not matter if you are throwing discraft discs or innova discs, there are overstable, stable, and understable discs from every manufacturer.

A stable disc could be a Discraft Comet for one golfer or a Wasp for another. It could also mean the disc will not turn right and will finish left every time, say an Innova Firebird (big arm) or a Cheetah (not so big arm). Add the word ‘way’ in front of stable and you could have an XXX by Latitude 64 in your hands, depending on whom you are talking to.

Stability, unfortunately, is next to impossible to accurately determine for all discs and all disc golfers across the board. The generally accepted definition is the tendency of a disc to hold its forward trajectory.

There is one major factor missing: the infinite number of variables. Under what conditions is the disc being thrown – temperature, wind, precipitation, etc? Who is throwing the disc – a beginner or a touring pro? What elevation is the disc being thrown at – sea level or the Rocky Mountains? Deeper and deeper down the rabbit hole we go…

The only solution, other than studying every disc in every weight at every stage of wear, thrown with every possible combination of variables, is to start from an explicit standard of stability. I will keep it simple.

WARNING: My understanding and explanation of disc stability is not absolute. After years of study I have not found a clearly stated, universal evaluation that takes into consideration all conditions and factors, thus, the following discourse.

The first part of the equation – who is throwing?

The most widely known golfer to use for this example is our imaginary friend, the fictitious ‘average pro’, with a nice round PDGA rating of 1000. If you are not familiar with PDGA ratings, you can find ratings frequently asked questions, search for 'pdga ratings faq'.

For this article, we will call him Joe, or Bill, any damn thing but Sue – sorry, I couldn’t resist!. This right-hand, backhand Joe throws about 425 feet for max golf distance but can pump it out close to 500 when throwing for distance competitions. He has a very good understanding of mechanics and form, and he is a very good putter.

Joe can throw a putter 300 feet, but very rarely finds the need to do so in competition. His mid ranges travel roughly 300-350 feet and his fairways about 350-400. There are relatively few holes requiring distance drivers due to Mr. Average’s distance.

Next, how is the disc thrown?

For ease of explanation, let’s start with the goal of throwing straight, flat, and at a moderately low height, say 8-10 feet off the ground at around 85% power, 100% being as hard as possible.

A stable disc (at high speed) will hold a straight line with little deviation for around 75-85% of its flight and fade left (RHBH, reverse for lefty or forehand) at the end when thrown by our Average Joe.

An over-stable disc will turn left much earlier in its flight and many times skip, especially with wide rimmed distance molds.

An under-stable disc will turn right – sometimes early in its flight and may even roll depending on flight characteristics and condition of the plastic. Starting from this baseline allows us to discuss disc flight in a common vocabulary.

The variables are endless. Innova discs, Discraft discs, and any other disc manufacturer produce unique molds and unique discs. Consistency between runs has an effect on stability. Go ask your local pro and see for yourself.

The above does not take into consideration a disc thrown at 50% power, in which case low speed stability becomes a major factor. Nor does the example define at what elevation the disc is being thrown. A disc thrown in Denver, Colorado, elevation one mile – 5,280 feet, is drastically more stable than the same disc thrown in Rock Hill, South Carolina, elevation 675 feet.

Without knowing where a golfer plays it is very difficult to say if an Xcalliber is stable or over-stable. One 1000 rated player may say it is super over-stable while another 1000 rated player says it is straight as an arrow stable. Both may be accurate if one is playing Bozeman, Montana and the other in Seattle, Washington – a 4500 foot elevation difference.

To add to the confusion, disc manufacturers do not make every disc exactly the same… More on this in Part Duex.

Throw It Long!