Backhand vs Forehand spin rate (TechDisc)

[Nick Carroll]

We're seeing some impressive numbers on the TechDisc website. Using their Throw Explorer, you can see the different stats per throw type (among other things). It's interesting to me how much faster the spin rate of the backhand throws are compared to forehand throws, even though there's much less of a speed discrepancy. I feel like this range of differences has started to become more well known, but I've been happy to see some validation of this knowledge by technical means here:

Throw Explorer

techdisc.com

Click Show Filters and then Throw Type if you want to get an idea. As of now it's almost 1000 forehand throws and over 3300 backhand throws - good sample sizes - many of the top examples coming from touring pros.

 

[Sheep]

This is on my "to do list" for studying with video and high speed.

The basics of it is, a backhand leverages more of the disc than a forehand.

I had this figured out forever ago and people just wanted to argue with me about it.

The problem is, I wanna figure out how much leverage forehand vs backhand.

But it was easy to figure out that forehands have less spin. Which means less leverage.
While backhands you can do crazy things to add or loose spin in your throw alone that forehands cannot do.

 

[timothy42b]

But it was easy to figure out that forehands have less spin. Which means less leverage.
While backhands you can do crazy things to add or loose spin in your throw alone that forehands cannot do.

This looks like it might add some spin to a slower forehand, and might be similar to the crazy things you mentioned on backhand.

 

[blayed]

I think it was @Sheep who told me that for BH roughly half of the disc constitutes a "lever arm" whereas on a sidearm its only roughly a quarter of the disc, which seems right. That's why generating spin and reducing OAT is so important on a FH but basically trivial on a BH.

 

[txmxer]

in the archives on disc flight, there is a lot of discussion on spin and it's effects.

Lots of debate on the physics, some more technical than others, but the difficulty has always been testing the ideas. With this new tech we should be able to really advance/confirm/correct our understanding of disc flight.

 

[Nick Carroll]

This is on my "to do list" for studying with video and high speed.

The basics of it is, a backhand leverages more of the disc than a forehand.

I had this figured out forever ago and people just wanted to argue with me about it.

The problem is, I wanna figure out how much leverage forehand vs backhand.

But it was easy to figure out that forehands have less spin. Which means less leverage.
While backhands you can do crazy things to add or loose spin in your throw alone that forehands cannot do.

Yeah I wondered about this a few years ago, then I saw a Dynamic Discs Physics of Flight episode that showed backhand had faster spin from the pros tested there - and by a pretty significant amount, something along the lines of 30-40%. From there I searched on these forums and there was mention of an Erin Hemmings study that found something like 25% difference, back in 2008. That pretty much sealed the deal for me, but I've always wanted some technical verification beyond studies with small sample sizes. And now we have that via these new gadgets.

 

[Sheep]

I think it was @Sheep who told me that for BH roughly half of the disc constitutes a "lever arm" whereas on a sidearm its only roughly a quarter of the disc, which seems right. That's why generating spin and reducing OAT is so important on a FH but basically trivial on a BH.

That was me guessing.

I wanna find out more accurate numbers on it. Just... gotta mount a camera to my ceiling and make it remoteable.

 

[HyzerRoc]

When clicking on the individual throws you can see how the disc moves. Invariable, people do a little loop before sending the discs forward like in these two:

Tech Disc

techdisc.com

Tech Disc

techdisc.com

It reminded me of the gif @HyzerUniBomber made of Nate Doss a while back. Just that you now get this path with every throw they took data of.



Also, anyone has a clean excel sheet of the whole data table or knows a way to export the data into one?

 

[timothy42b]

Lots of debate on the physics, some more technical than others, but the difficulty has always been testing the ideas. With this new tech we should be able to really advance/confirm/correct our understanding of disc flight.

I think the effects on disc flight through the air are well understood; there are several good resources out there. They aren't easy to follow, as they talk vector cross products, right hand rule, and moments. But I don't think there's any debate on what spin does. It seems to me the debate is more on exactly how the spin gets on the disc. (not everybody who throws really far understands the math, so you'll hear some goofy ideas)

The new tech does seem to be a good way to know just how much spin is on a given throw, and to check if what you're doing is affecting it. Ball golf has had that technology for years. Every launch monitor gives spin numbers.

I would like to see disc golf stores with those monitors and a net. I'd go pay $5 to throw into a net a couple of times. A store should make that $300 back pretty quickly.

 

[Sheep]

I think the effects on disc flight through the air are well understood; there are several good resources out there. They aren't easy to follow, as they talk vector cross products, right hand rule, and moments. But I don't think there's any debate on what spin does. It seems to me the debate is more on exactly how the spin gets on the disc. (not everybody who throws really far understands the math, so you'll hear some goofy ideas)

The new tech does seem to be a good way to know just how much spin is on a given throw, and to check if what you're doing is affecting it. Ball golf has had that technology for years. Every launch monitor gives spin numbers.

I would like to see disc golf stores with those monitors and a net. I'd go pay $5 to throw into a net a couple of times. A store should make that $300 back pretty quickly.

You, unfortunately, couldn't be more wrong about peoples understanding of disc flight and spin. The things people will argue with you about on disc flight or how discs do this or that is absolutely insane.

I think there are some of us who understand it better than others, but the majority of everyone doesn't.

The tech stuff is neat, but the problem with it is we don't know its accuracy. So, do we treat it like a dyno, or actual data?

That's a lot of little sensors to pack in that sensor pack, and its trying to read a LOT of sensors at once. And based on the stuff I was seeing with OT .... well, it was dumb what they were doing, but whatever. I'd be pretty susspect of some of the data such as speed, but I think that spin is a good one we can use off of it. I'm also a bit susspect of nose angle on it as well.

It's a toy at the moment to be honest. But a fun toy. It's like buying a speed gun and thinking it will make you throw better. It wont.

 

[Sewer bill]

You, unfortunately, couldn't be more wrong about peoples understanding of disc flight and spin. The things people will argue with you about on disc flight or how discs do this or that is absolutely insane.

I think there are some of us who understand it better than others, but the majority of everyone doesn't.

The tech stuff is neat, but the problem with it is we don't know its accuracy. So, do we treat it like a dyno, or actual data?

That's a lot of little sensors to pack in that sensor pack, and its trying to read a LOT of sensors at once. And based on the stuff I was seeing with OT .... well, it was dumb what they were doing, but whatever. I'd be pretty susspect of some of the data such as speed, but I think that spin is a good one we can use off of it. I'm also a bit susspect of nose angle on it as well.

It's a toy at the moment to be honest. But a fun toy. It's like buying a speed gun and thinking it will make you throw better. It wont.

It would be pretty simple to setup a camera and throw an above and side profile with a reference background to verify if the sensors are accurate, and for disc golf even a +-5% would be significantly useful for data collection and form work.

Personally, I have no doubt the cheap off the shelf mems(microelectromechanical) gyros used in these smart discs or smart sticker pcbs to measure velocity change and heading position are stupidly accurate.

Whether they're calibrated correctly with well written software or can be tricked by off axis torque is another topic. I have 3 dollar mems pcbs from China from the early 2000s for custom rc helicopters and multirotors that can sample at rates so high that the length of trace on the pcb(sub mm) can actually effect the results in final setups, things like a 1 thousandth of an inch bend in a tail rotor shaft swinging a prop 20 thousand rpm can be picked up and adjusted nearly instantaneously to offer servo feedback(this is how people burn up servos in high end 3d helicopters) it's also why mems gyros have to be dumbed down to dampen the input data because they are so damn sensitive to rate of change.

We, the industrialized world, have perfected growing micro machines out of silicon to the point where there's one in every phone and only the really fancy ones that run two or more simultaneously to check eachother are used for industrial robotics or weapons systems.

The goal is to treat it like an automotive dynamometer, to infer useful data and filter the noise but without knowing the specifics of the software it's hard to say what they have the sample rates setup at and whether they're adjustable and what they're including or leaving out. A single mems gyro could absolutely plot out millions of points of data in a single rpm of a disc but that is too narrow of a use case for these types of products and we need actually much less information than they could on paper provide.

 

[timothy42b]

You, unfortunately, couldn't be more wrong about peoples understanding of disc flight and spin. The things people will argue with you about on disc flight or how discs do this or that is absolutely insane.

You're probably right. All of my ball golf friends know how the spin gets on a golf ball. But that isn't really how it happens.

 

[Sheep]

You're probably right. All of my ball golf friends know how the spin gets on a golf ball. But that isn't really how it happens.

The issue is that we don't ever really wanna feel dumb or seem dumb.
We think were good at disc golf, so we think we know it all.

It's just the Dunning Kruger effect. And its everywhere all the time.
For anyone who doesn't know, it's a chart/curve based on actual knowledge, and perceived knowledge. This is what stems the idea of "you don't really know anything until you know what questions to ask." Or some things similar to this.

Were currently stuck with a bunch of youtubers who are stuck in this effect and have no clue, even when they are told. They are at the start of it, they know they are not 100%, but they think they know more than everyone else. But they really don't know a whole lot of anything.
This is why Josh and Trent and so many others get slammed by anyone with actual coaching knowledge on disc golf. But nobody but a few of us will just outright say "that is wrong, you need to do better."
Everyone is to busy trying to suck them off because they are on the bandwagon, or because they want to ride their glory.

Until these guys have any level of realization that they don't know what they think they know, they are not informed coaches to me. They might step on a few good idea's here or there, but they are usually from others.
And this is why I complain about coaches not talking enough. It's because you'll never get questions unless you talk. You'll just live in your echo chamber forever and ever.

And this is what happens with spin and flight. I have lots of questions. I want the answers. I'm going to get the answers. I just know our current understanding is really poor on the subject, nobody has looked into it at all, they just make wild assumptions and accusations.
And if you say ANYTHING to the contrary, they will try and shred you.

I'm just done with the stupidity of online coaches. I tried to be nice. I tried to help a bunch of people. And most of them are to concerned with all the wrong things. I wanna be good at what I do, and learn. I have no effing clue what they are doing other than sponsored ad's and really crappy experiments throwing through a doorway in what looks like some dudes garage turned into an air bnb.

 

[Ryan P.]

What's the longest throw anyone has been able to calculate on their simulator? 3D Throw Viewer

 

[Nick Carroll]

What's the longest throw anyone has been able to calculate on their simulator? 3D Throw Viewer

Backhand is 603' currently. Forehand is 485'. It's quite possible there were earlier data sets, and longer distances for each. I'm only aware of the current set.

 

[BrotherDave]

This is on my "to do list" for studying with video and high speed.

The basics of it is, a backhand leverages more of the disc than a forehand.

I had this figured out forever ago and people just wanted to argue with me about it.

The problem is, I wanna figure out how much leverage forehand vs backhand.

But it was easy to figure out that forehands have less spin. Which means less leverage.
While backhands you can do crazy things to add or loose spin in your throw alone that forehands cannot do.

If I had to guess it's because backhand is a longer lever from disc to bracing foot. It's really difficult to achieve as long a brace with forehand as you can backhand.

 

[sidewinder22]

 

[sidewinder22]

 

[Brychanus]

(two combinations)

This comparison of the two is interesting and a couple pros come to mind that would map to each. I wonder how many combinations exist that would predict 600'+.

 

[Ryan P.]

After a lot of tweaking, I broke 700. 3D Throw Viewer

There's also a parameter in the URL for wind, but there's nothing on the site to adjust it. 1,920. 3D Throw Viewer