# An approach of understanding Verta-Tune



## MrPhil (Aug 14, 2017)

Oh god, I'm sorry for the horrible layout in the first post. I'm unable to edit it, so here you go again...


I would like to gain a better understanding of the Hoyt Verta-Tunesystem to optimize my bow for my individual needs.

Please refrain from giving the typical "trial and error"-advice, and I'm well aware that tinkering with this topic is not relevant for shooting world class scores. I also know that my time is better spent on the shooting line, but I'm a physicist so thinking about this stuff is part of the fun.

Anyway, I have a particular example (mine) in mind:

I shoot a normal Olympic Recurve bow, using a 27" Hoyt Faktor with long limbs with the typical Hoyt High Wrist grip. My pressure point is on the lower side due to rather large hands. I've chosen the high Verta-Tune plate for my initial setup since Brady also used it on his 27" Faktor. My tiller is +3mm and importantly, but my nocking point height (NPH) is on the higher side with ~16mm (measured from arrow rest to lower edge of upper NP using ACE 570 arrows).

The bow shoots and tunes decent, but I would like to find a setup with a lower NPH for testing purposes.

My idea consists of changing to the *low* Verta-Tune plate, thus reducing the distance between arrow rest and pressure point. This will make the lower limb work harder such that I can either reduce the tiller *or* reduce the relative NPH. Is this correct or is there any mistake in my thinking?

If this idea is correct, the Verta-Tune plates can be used to adjust the modern Hoyt bows to the individual archer in a rather systematic way, i.e., if you have a rather low pressure point think about using the low plate and vice versa. Obviously, this needs a careful evaluation of the individual shooting form as finger pressure and release direction also influence the NPH. But it seems almost nobody has the slightest clue how to use the Verta-Tune system for tuning.

I'm looking for fruitful discussions!


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## tunedlow (Nov 7, 2012)

MrPhil said:


> Please refrain from giving the typical "trial and error"-advice, and I'm well aware that tinkering with this topic is not relevant for shooting world class scores. I also know that my time is better spent on the shooting line, but I'm a physicist so thinking about this stuff is part of the fun.


Like science, trial and error is the part of the process of tweaking your archery setup and is, in fact, very relevant to shooting well with your bow so you aren't fighting against it. Looks to me that the application of the vertatune plate is to change the level of the rest height that is used with a particular arrow size. On a non-verta tune riser, folks would just loosen the hex bolt on their rest and adjust for the size of a different arrow. In your case, changing to a low verta tune rest would still require trial and error testing because I would put more stock in the grouping of arrows on a target face to determine where my nock height should be and adjust the tiller to suit as well. I don't think there is a way around evaluating arrow shot patterns plus the shooting form/finger pressure that is used to tune and shoot the bow because tweaking the equipment should be based on those parameters to ensure that the bow and archer is optimized together properly.


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## MrPhil (Aug 14, 2017)

You are right, but I intentionally asked to avoid this discussion because I'm well aware of these points.
I simply tend to test stuff only after having a hypothesis of what will change, and in this matter I'm not sure, hence seeking for feedback. 
But using this approach for testing stuff, i.e., testing with an hypothesis in mind, I will end up with an deeper understanding of what is going on, not only with experience. This is also what you do in science.

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## MrPhil (Aug 14, 2017)

tunedlow said:


> I got nothing, then. Seems like there is a dichotomy of being aware of the need for testing but simultaneously not wanting to discuss relevant parameters that cause variation in performance and outcome of the shot patterns. I guess pick the low veratune and see how it works with your hypothesis -whatever it is. I am a scientist and the point really doesn't make sense to me but good luck!


I don't see where you try to discuss relevant parameters, you only state that I should test and evaluate the performance. But this is common sense and obviously the next step as I stated in my first post. However, since changing the plate involves moving the rest or buying a new one, I would rather make sure that my goal of reducing the NPH (and possibly the tiller) can be most likely achieved by this approach. This was and is still my question. The ability to generalize it to any archer could be a follow-up topic.


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## theminoritydude (Feb 11, 2013)

MrPhil said:


> The bow shoots and tunes decent, but I would like to find a setup with a
> lower NPH for testing purposes.
> 
> My idea consists of changing to the *low* Verta-Tune plate, thus
> ...


Vittorio has a post somewhere in the forum that specifically addresses the issue of a high verta-tune setting vs a low setting, which may at first seem rather counter-intuitive, but makes sense as long as one considers the problem to be that of error management (how to position your settings at a region of minimum range of error and sacrificing a rather negligible amount of efficiency, instead of maximizing efficiency by attempting to operate in a region that if one fails to stay within, results in a larger range of output errors. Did I get it right Vit?), rather than that of trying to close up the gap between force vectors.

I'm reading your question as the intention to set the bow up in a way that does not specifically pursue efficiency, but merely to 'clean up' some asymmetry that seems to bother you (does it?). These asymmetries exist because, well, there is no way to shoot the bow through your hand, and there is the issue of gravity.

The truth is, tuning is a process that involves trials and errors. Without trial and error, there is no tuning. That is called "setting".


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## tunedlow (Nov 7, 2012)

MrPhil said:


> I don't see where you try to discuss relevant parameters, you only state that I should test and evaluate the performance. But this is common sense and obviously the next step as I stated in my first post. However, since changing the plate involves moving the rest or buying a new one, I would rather make sure that my goal of reducing the NPH (and possibly the tiller) can be most likely achieved by this approach. This was and is still my question. The ability to generalize it to any archer could be a follow-up topic.


The relevant parameters i mentioned are evaluation of the shot patterns on the bale. How you shoot is a parameter, and an important part of tuning at that. This is common sense to anyone tuning a bow. Your question is can you reduce NPH with a low vertatune plate? Possible. I've seen a high plate used on fat arrows so if you want a lower NPH, a low plate may give you what you seek. Will it possibly give you the tiller setting you want? Depends how you shoot.


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## Viper1 (Aug 21, 2003)

MrPhil -

Seeing as I'm pissing people off today, I guess it's your turn. 

The "Verta-tune" thingy ain't new. Hoyt tried a similar setup back on old Gold Medalist risers, it was as much of a flop then as it is useless now. 
In general terms, you want the arrow to rest as close to the pivot point as possible while maintaining adequate fletch and hand clearance. The guys who designed the bow put the plunger hole (rest area) in the optimal place. 

What you are describing can and is accomplished by basic tuning with nock point and tiller. The Verta-tune is just more marketing Hype. So, the real answer is the one you didn't want, if you "think" you have to use it, or it will be any kind of benefit, you're going to have play with it and then adjust the rest of the tune to compensate. 

And for the record, while you gave a good description, you didn't mention how long you've been shooting and what scores you're averaging. That's kinda important. 

Viper1 out.


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## MrPhil (Aug 14, 2017)

theminoritydude said:


> Vittorio has a post somewhere in the forum that specifically addresses the issue of a high verta-tune setting vs a low setting, which may at first seem rather counter-intuitive, but makes sense as long as one considers the problem to be that of error management (how to position your settings at a region of minimum range of error and sacrificing a rather negligible amount of efficiency, instead of maximizing efficiency by attempting to operate in a region that if one fails to stay within, results in a larger range of output errors. Did I get it right Vit?), rather than that of trying to close up the gap between force vectors.
> 
> I'm reading your question as the intention to set the bow up in a way that does not specifically pursue efficiency, but merely to 'clean up' some asymmetry that seems to bother you (does it?). These asymmetries exist because, well, there is no way to shoot the bow through your hand, and there is the issue of gravity.
> 
> The truth is, tuning is a process that involves trials and errors. Without trial and error, there is no tuning. That is called "setting".


I'm fairly sure that I've read Vittorio's post as well, and it's insights were part of the reason why I'm using the high plate right now. But I think he was also stating that there is an optimal distance between pressure point and rest height which the Earl Hoyt geometry got right. 

Now if this optimal distance exists and the Earl Hoyt geometry got it right, the average archer should use the middle plate. However, in case of a rather high pressure point one should use the high plate and vice versa for a low pressure point. Do you agree? Defining what is a high or low pressure point is a different story.

You are correct about calling this "setting". But imho, anything beyond basic basic bareshaft and walk-back tuning is a waste of time for an ordinary archer like me. It requires statistic long-time testing to come to a meaningful conclusion. Therefore, such fine-tuning steps like verta-tune plate height should be rather *set* to what you think is the optimal choice.
You could argue that I'm contradicting myself because I'm aware that it is not relevant, but let this be my problem.
You are also right about my concerns regarding the balance of force vectors. I understand that it is not necesserily bad to be slightly off to have a more forgiving bow, but balanced forces might help me holding steadier, and this is actually one of my problems while shooting right now. Efficiency is indeed not a major concern.


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## MrPhil (Aug 14, 2017)

Viper1 said:


> MrPhil -
> 
> Seeing as I'm pissing people off today, I guess it's your turn.
> 
> ...


Don't worry, I don't get pissed off easily.

As you state, I should go for the lowest Verta-tune plate as long as long as I do not experience any clearance issues. Can you elaborate on why having the rest as close as possible to the pivot point is the best option? I'm wondering since there are arguments against it (see the previous posts in this thread).

Actually, I found the Gold Medalist instructions for the Verta-tune today and they were simply stating that it could be used for fine-tuning regarding pressure point etc., but no instructions on what to do exactly. And I have to agree that it is probably impossible to give an universal advise as it comes down to the individual archer.

I'm shooting for about 3 years, averaging 560 rings on a normal 70m round. Hence, I will not be able to distinguish between the different verta-tune plate positions by comparing my average scores.


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## Viper1 (Aug 21, 2003)

MrPhil -

Assuming the riser and limbs are properly matched you kinda want the forces from both limbs to be fairly equal on the arrow at launch and the hand to be centered on the bow's forces as well. Since that's physically impossible, there has to be a compromise, and we usually want that compromise to be as small as possible. 

If the limb forces on the arrow weren't nearly equal, you'd get up and down flirting, and if your hand (pivot point) wasn't nearly centered on the riser, the bow would feel like it's pull up or down on the draw and be uncomfortable at anchor. 

I'm sure there are more technical reasons for playing with rest position, but to my way of thinking, if it doesn't affect my shooting, it's not worth worrying about. 

With the GM most every one I knew just dropped the plunger bushing as low as possible and forgot about it.

Viper1 out.


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## MrPhil (Aug 14, 2017)

If most GM shooters used the lowest position, why isn't this the case nowadays? The riser geometry should be the same, so what has changed? Almost everyone sets the mid position and leaves it there.

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## lees (Feb 10, 2017)

MrPhil said:


> If most GM shooters used the lowest position, why isn't this the case nowadays? The riser geometry should be the same, so what has changed? Almost everyone sets the mid position and leaves it there.


The reason is it doesn't make enough difference on the recurve bow to matter where it is, within the "vertatune" range, so it's usually set with the TLAR method (That Looks About Right). And everyone just forgets about it and goes shooting.

I had a TD4+ GM back in college which had the vertical adjustment and I can confirm Viper's report on its worthlessness. Its only apparent use seemed to be just to come loose in the middle of a round. It served no other detectable function that I was ever able to find.

From the compound perspective, however, the rest height does make a measurable difference in how the bow tunes. In terms of the geometry, the operative factors are the same, but even small movements of 1/4" up or down, for example, are much larger in magnitude relative to the ATA length of the compound bow vs the typical olympic style recurve. So the tillering (both offset limb poundage and wheel/cam detiming) actually does produce a measureable change in the knock travel as the bow discharges.

The general variables and I mean very general, are:
- the higher the knocking point above the center of the string, the closer the grip can be positioned to the string center, improving the hold of the bow. But this also has the effect of requiring more positive tiller (more poundage on the bottom limb, or timing the bottom cam fast) to avoid a knock-high on the bareshaft.
- the closer the knocking point to the center of the string, the further down from string center the grip has to be, which can make the bow feel skiddish in the hold (bowarm has to be held lower, especially at shorter distances). But this reduces the amount of tillering required to keep a flat bareshaft.

The other item is where the pull of the string is centered with respect to the knocking point. On the compound bow shot with a d-loop and release aid, these are in very nearly the same spot on the main string; with a finger release on any bow, the center of pull is below the knocking point by some amount. With a 3 under hook, that's probably the furthest down, and a 2 finger split hook, that's probably the closest to the knocking point.

Again, on the compound bow, for a finger release, the knocking point is usually raised above the center of the string to help account for this. And raised a bunch, sometimes as much as 3" above the string center (like my hoyt tribute finger bows). Meaning, not as much tiller is required for tuning with a finger release because the center of pull is closer to the string center than it otherwise would be. Where a d-loop/release aid is intended, usually the bow is designed to have the knocking point closer to the center of the string (and in some modern cases like my PSE shootdown, slap dead-on the string center).

Anyway, those are the general geometric principles for the different design choices as well as I've been able to learn them over the years. I may be wrong on some of those, so this is worth only what you paid for it. But to the best of my knowledge, this is generally the why's and hows of it....

lee.


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## Viper1 (Aug 21, 2003)

MrP -

Can I call you MrP now that we've been talking a bit?



MrPhil said:


> If most GM shooters used the lowest position, why isn't this the case nowadays? The riser geometry should be the same, so what has changed? Almost everyone sets the mid position and leaves it there.


Nothing changed and Lee is correct, it's about it looking right. (aka the 3 Bears theory)
Remember the current VT has three plunger positions, the old GM bushing just slid up and down.
keeping it low follows the old theory that you can't fall off the floor. 

Viper1 out.


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## tunedlow (Nov 7, 2012)

Viper1 said:


> MrP -
> 
> Can I call you MrP now that we've been talking a bit?
> 
> ...


I am curious -if the 2 plunger design was enough -why is Hoyt bothering with this whole Vertatune thing enough to even bring it back from the GM days when it was a flop of a feature? From an engineering perspective, if the 2 plunger buttons were sufficient and people continue to shoot world class scores with them, adding a movable bow feature that could fail doesn't really make sense much.


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## Viper1 (Aug 21, 2003)

tune - 

Marketing.
It's not the first time and won't be the last it's been done. 
Hey, they have a right to make money, and we have a right to go elsewhere. 

Viper1 out.


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## tunedlow (Nov 7, 2012)

Viper1 said:


> tune -
> 
> Marketing.
> It's not the first time and won't be the last it's been done.
> ...


Gotcha. I was just wondering if there was any legit merit to it. The Vertatune reminds me of those Hoyt string stoppers that came out not long ago.


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## Viper1 (Aug 21, 2003)

tune -

I'm sure it helped somebody, somewhere...:zip:

Seriously, the only benefit I can imagine is with some really ham-handed giants who's hands ride over the shelf and the standard position rest could have resulted in hand cuts from the fletch. Yeah, it's a stretch, I know. 

Viper1 out.


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## tunedlow (Nov 7, 2012)

Viper1 said:


> tune -
> 
> I'm sure it helped somebody, somewhere...:zip:
> 
> ...


Them must be some big hands!


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