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.
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
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.
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.
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!
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 read that right. I’m actually encouraging the use of a beat-up disc, and it may be the first (and only) time you will ever see or hear that. In ordinary circumstances, I am strongly against using worn-in discs, and I equate “worn-in” with “worn-out”.
Hand-feel: It’s so deep, so blunt, and so sharp!
We could perhaps call the Sinus a “Negative Driver”, in that its ultra-sharp edge faces down rather than forward, and instead of a shallow rim with a very blunt bottom edge for the distal index joint to engage with, Sinus has a very deep rim with a very sharp bottom edge. Thus, the hand-feel is also unique, and a Sinus may not initially feel good in your normal power or control grip. If this is true for you, I encourage you to ignore the normal advice of making hand-feel a crucial part of your disc selection process, when considering the Sinus.
The innate ability of the Sinus to get you out of trouble, or onto the lead card can’t be underestimated, and this means you should persevere with a Sinus and become accustomed to its unusual hand-feel.
Other information about the Sinus
Flight Rating of the Sinus – questionable at best
Initially, Latitude 64 rated the Sinus as 2 1 0 3 but later changed it to 2 2 0 2.
Now that is a big change, and I am not sure what the rating for a Sinus should be. I certainly treat it like a 2 1 0 3 disc, and I feel perfectly comfortable using full power with it, knowing it won’t do anything funky on me, and it will end up pretty much where I want it to go, no matter what type of shot I am executing.
There are discs which glide less than a Sinus, but I would suggest they should have a Glide number of 0, and not 1. The Reptilian Stego disc in my view should be Glide 0. In addition, other discs with Glide of 2 definitely fly further than the extremely blunt-nosed Sinus.
But, who cares? Flight Ratings are only semi-helpful around half the time. See our much-read article on the Flight Rating system to find out why.
Shots to play with a Sinus
It would probably be quicker to describe the shots you wouldn’t use a Sinus for! Personally, I max-out at around 70-metres with my Sinus, but power players will reach 90 or 100-metres with it.
Most of the time I throw a Sinus flat, and relatively low, to ensure straight flight with good fade, and easy ranging. But I will also throw it high on a spike-hyzer, confident it will buckle when it spears in, taking out its energy and causing it to bounce, rather than skip, or roll away from my landing zone.
The Sinus is also pulled out for high anhyzers that need to reach right and land flat.
I also putt with it into headwinds, but never on a hyzer; always on a gentle anhyzer so there is no chance of the disc lifting. Similarly, I use it for uphill and downhill putts and approaches where I need the disc to grab the ground close by if I miss.
In the wind it’s my go-to approach disc because of its lack of glide, and (normally!) predictable flight path once the flight plate is exposed to the force of the wind.
Sinus is also very valuable for radical forehand anhyzer upshots where that's all you've got, and you absolutely have to make the landing zone and stick on it.
Sinus as a putting putter
I was so enthusiastic about the Sinus I used it as my main putting putter for three years. Putters just don't matter until you get outside 7-metres, and I don't make a high percentage of putts beyond that range normally.
Beyond 7-metres, Sinus definitely starts to show its overstable flight path, even with only the smallest amount of spin, and this means it deviates from its thrown line, and hence your aim point becomes some nebulous point in space to allow for the fade. That is not easy.
Eventually, I switched to a Dagger (also on Feldberg's strong advice) and then finally, to the RPM Ruru, which is Dagger V2.0, effectively.
For headwind putts, Sinus can be counted on not to climb, provided no hyzer angle is used. Ideally, you will shoot Sinus with anhyzer so it is descending constantly, so if you miss the basket completely, it should still be gettable.
Care and maintenance of your beloved Sinus or other Zero plastic disc
As I mentioned above, Sinus is beautifully tacky when new. This is because the pores on the surface of Zero plastic are large and empty, providing great grip whether wet or dry. However, Zero plastic absorbs dirt and dust like a sponge.
As the pores in the plastic fill up with dirt and dust the tackiness and grip drop substantially. Periodical and fairly energetic cleaning of the disc with methylated spirits is a good way to remove gunk from the pores and restore the tacky nature of the plastic.
Lacquer thinner works even better as it is extremely aggressive, so take care as it will remove most stamps with just a few wipes. It can also start to dissolve some disc plastics if you rub hard.
How I converted to the Sinus and became a true believer
I had been a big fan of David Feldberg’s playing and teaching ability for a long time, and greatly admired his no-nonsense approach to disc golf and the way he broke it down in his instructional videos – two of which I host on YouTube: Here and Here.
When Dave switched to Latitude 64 from Innova, he promptly won an A-tier in Las Vegas, beating Will Schusterick on the final hole with a massive 90-metre headwind approach, which he successfully parked with a Sinus. Shortly afterwards he made an In-The-Bag video where he sang the praises of this new disc. Here it is, cued up for you:
Timestamp 8:12 for the Sinus.
I took that advice, and bought two, and then not long after another one, and another one, and another… and today I have 11, but I've had as many as 14.
Years later in 2015, when I finally met Dave, who I share a birthday with, and spent quite some time with him and Synthia, I asked him to sign some discs, and he was happy to oblige. I pulled out my stack of 10 Sinuses, and he asked me with some incredulity, “Chris, why have you got so many Sinuses?” and I replied, “Because you told us they are excellent, and to go and buy them. So that is what I did.” He laughed loudly, told me I had done good, and then happily got busy with his sharpie.
Grabbing my first Sinuses was one of the best Pro-Tips I ever took, so why not grab one today? We have good stocks of Soft, Medium, Hard, and Zero Burst Medium.