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  • Chris Davies. Edited by Martin Galley

Best-Kept Secrets in Disc Golf: The Latitude 64 Sinus

Unlike almost every other disc in the world, the Sinus is truly unique – and I use this word as defined: “being the only one of its kind; unlike anything else.” In this article, I go through the features and benefits of the Sinus and explain why it’s a necessary addition to every bag.

The Sinus gained PDGA approval in early 2006, so it has been a fixture of the sport for some time now, and yet the general playing population has not discovered the magic Sinus can unlock once its powers are properly understood.

My current Sinuses, including tasty Raspberry, Chocolate, and Pine-scented, thanks to DF12626

It is an overstable, low-glide, very deep, small-diameter putt and approach disc with a savagely sharp bottom rim. It has three rounded patches of varying roughness on top of the flight plate. It is available in Zero Soft, Medium, and Hard plastics only, but I have fantasies about a Gold Line or Tournament Sinus.

Sinus is one of my most-thrown discs, and fills a variety of roles and gets thrown in a number of ways. Being without one on the course makes me feel semi-naked and not properly equipped.

When someone buys a Sinus from me, it’s not so much me selling one, as the new owner almost instantly recognising the characteristics and abilities I describe below and understanding how valuable they are, and what a Sinus can add to their game.

The key features and associated benefits of the Sinus

Figure 1: Sinus Flight Chart by Latitude 64

Overstable with a strong fade

The overstability of Sinus means it is a superb driving putter and handles full power throws without turning over. Its reliable and consistently overstable flight shape, and predictable and strong fade reduces the potential landing area of Sinus so that it is one of the most accurate discs you can ever throw. See Figure 1.

Glides like a plastic brick

The deep dish and very steep ramp below its Parting Line means Sinus glides like a pile of poop and does not fly in the conventional sense of the term, as it develops no Bernoulli lift over its top surface, and is best described not as a “flying disc” but as a “spin-stabilised ballistic disc”.

With only direct mechanical lift to rely on, Sinus is extremely easy to range, and this combined with strong fade at the end of its flight means you will almost never overshoot with it.

Mechanical lift is what keeps aeroplanes in the sky; it is when the mass of air deflected downwards is the same as the mass of the aircraft. Bernoulli lift simply makes aeroplane wings more efficient and provides superior handling characteristics.

Close-up profile of Latitude 64 Sinus leading edge
Figure 2: Very steep ramp below the Sinus leading edge

Due to the lack of lift and glide (Glide is defined as Lift divided by Drag, or G=L/D), a Sinus will not climb when thrown flat into a headwind – and this is very important (see our Wind Gradient article to discover why) because it makes Sinus a superb disc for throwing into the wind – and some old Sinus stamps proudly proclaimed the motto “Non sinet tactus venti” which is Google-Latin for something approximating “The wind doesn’t/can’t touch it”.

In the wind, and on tricky upshots, if I can reach it with a Sinus, then I reach for a Sinus. This is often my motto on the teepad as well, and why a Sinus is my preferred driving putter if fade is allowable and range is critical. I say,

“If I can reach it with a Sinus,

why would I throw anything else?”

Choose your thumb texture

The Sinus has three different rounded surface patches on top of the flight plate. Each patch is rougher than the previous, so you can select one of four different surfaces for your thumb. My preference is for the roughest patch.

Click to zoom: one of three different thumb pads. Feldberg-approved.

This might not sound like a big deal, but when you have played with a Sinus for a while, you may come to wish many other discs offered the same feature.

Super-sharp bottom edge

Unlike any other golf disc, Sinus has an exceptionally sharp bottom rim. It is just as sharp as the leading edges of the fastest drivers, and this means Sinus grabs the ground like nothing else. Sinus does not skip, or slide much (if at all) when it lands, and even if it lands on hardpan, it will often grab a tiny root or protrusion, and come to a dead stop.

This landing-area reducing feature means you can rely on Sinus when the green is tight, or steep, or hard, or OB is close by. Or all of those things.

From the factory, Sinus is dangerously sharp on the bottom edge, and you shouldn’t attempt to forehand a brand new Sinus, as injury may result. This overly sharp nature is due to flashing created in the moulding process, and before use, you should carefully sand off the flashing to smooth the bottom edge into the shape of the mould it came from – and please, no more!

Sinus super-sharp bottom edge and flashing
Sinus: The sharpest bottom edge in disc golf. We recommend removing the tiny ridge of flashing.

Use 150-grit paper on a solid sanding block, and only sand horizontally to keep the bottom surface symmetrical and even. Work slowly and carefully, checking your progress constantly.

Once you’ve smoothed the bottom edge, it is ready for throwing – but be aware that if you fully engage the index joint and index finger pulp around the bottom edge and pressure the inner rim (as with a normal power grip) you may initially experience the occasional dreadfully inaccurate throw, where the sharp bottom edge hooks on your index finger, and the disc spears off to the far right. This is invariably great entertainment for your playing buddies.

There is no free lunch in disc golf – and the Sinus’s extreme ability to grab the ground comes at the expense of a slightly less predictable release. And so you will need to spend a little time coming to grips with how a Sinus comes out of your hand, particularly when using high power levels. You shouldn’t have any problem with throws at lower power.

Sidenote: The PDGA limits the sharpness of the leading edge of discs, and that is why all the high-speed drivers we play with have approximately the same diameter leading edge. However, the PDGA does not limit how sharp the bottom edge of the rim can be, and thus disc makers have total freedom in the profile of the bottom edge of a disc.

Super-grippy Zero plastic

Latitude 64 seems to have found the sweet spot with Zero Medium and Zero Hard, in my opinion. They are beautifully tacky when new, are sufficiently firm to take a proper power grip on without deforming noticeably and have a good lifespan, where no individual smack to the face will disable it, or change its flight shape to any appreciable degree.

Zero Soft Sinus is a tad too soft for my liking. It can deform in the snap when driven with full power, tends to develop an uneven/wavy flight plate over time, and each individual hit does more damage than to Medium or Hard versions. Ambient temperature significantly changes how soft it is, and I believe it is difficult to get a precise and consistent release if a disc deforms in your grip.

But if you like a Soft Sinus – that is you as a disc golfer deciding what you like, and good for you! :)

Durability and longevity

Due to the Zero plastic being substantially less durable than Gold Line, for example, Sinus does age faster than a premium plastic disc. *hint hint Lat64!* However, a Medium or Hard Sinus ages very nicely, and as it does so it begins to fly longer and straighter but retains the strong fade you’ve come to expect.

So, you could end up carrying two Sinuses; a new one and a beat-in one.

Yes, that is correct, you