How to understand Reflex and Deflex

September 14, 2015

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Archery   archery tips   Arrow Spine   Physics   recurve bow   Target archery  


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Understanding Reflex and Deflex risers

 

Thousands of years ago man did not have a true understanding of technology and how it affected the bow. Different styles of recurve bows were used in different cultures. By understanding the differences in their style of archery and hunting, you can see why some cultures chose different styles of bows.

 

Today we still toy around with different types of bows and when you are talking about recurves in competition you see manufactures selling you on the idea of a “more deflex” tuned bow. Understanding the purpose of what a more deflex bow does will help you gauge why all the hype is around today.

 

How well do you understand reflex vs deflex?

To make this simple for you to understand and not go into the science and technical aspects that most won’t understand, this article is a base to help you to get to know the difference and why they are important.

 

Reflex bows are designed to have the limbs pivot point in front of the archers hand or more easily to see in front of the grip pivot point. As you can see in the picture, this bow has a slight reflex design and puts the limb pivot points in front of the hand. (This is a deflex riser but with a more relflex design than normal. You will understand better later on.) The red line is drawn from the limb pivot point to show you the relation from the riser ends and the distance from the grip. 

 

Deflex bows are designed in the opposite way. The limb pivot point is behind the pivot point of the grip. Take a look at the picture and compare it to the one above to clearly see the difference. By using the red arrows you can see how the more deflex riser has more gap from the grip in comparison. You will notice this later on in the article as well. 

 

As for the definition of the two styles, this is as simple as it gets. Reflex and deflex simply refers to where the pivot point of the limb sits in relation to the pivot point of the grip. Simple right? You bet it is, at least until you start thinking about why the two designs and how they play a role in our shooting.

 

Reflex bows are much faster than a deflex bow design. There are several factors that come into play to make this happen. If you are up to speed on how brace height affects arrow speed, than this will be easy to understand. The lower the brace height, brace height is the distance from the throat of the grip, the faster the speed. We know this because by lowering the brace height you in turn weaken the arrow shaft spine, thus meaning more speed is introduced.

 

Purpose of each design has had its place in traditional archery designs and is now making its way back into the market.

 

If you have a short draw length and just cannot get the speed you are wanting, then a reflex design is more your speed. On the other hand if you are looking for a more forgiving bow and speed is not a concern, then a deflex bow is what you want.

 

 

In an age where speed seems to dictate what we buy, the idea behind a more reflex design bow has been a focus. Speed sells to the masses, but accuracy is what wins. With speed you will certainly sacrifice some accuracy. The trade-off is of personal preference in the end, but the end result for some is pin-point accuracy.

 

 

So how does each design make or break the archer?

 

If you are an incredibly accurate archer with little mistakes being made, then you can shoot a more reflex design bow. For the masses however, a more deflex bow is better and more forgiving.

 

 

Most recurve bows today are of deflex design. The question becomes how much deflex is built into the riser? Most entry level good risers have quite a bit of deflex built into them. The reason is simple. The more deflex the more forgiving the bow is and the more accurate. By giving a new archer a bow that shoots more accurately the more confidence they have quicker. The quicker they get better, the quicker they buy a new riser.  So why not make every riser with more deflex to begin with? The reason is because in the midst of having a more deflex riser with more accuracy, the less deflex riser is faster and faster wins in the wind and at distance. There is a trade-off remember and you can cross that fine line easily.

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Win & Win make mostly high deflex risers from the base range to the top end. Ask many archers why they love their Win & Win and they will tell you that the bow just seems to shoot better. Hoyt on the other hand has used a much less deflex design in recent years on their high end bows. They have found a balance with speed and stability, and it shows. Recently Hoyt have brought back the RX design which has more deflex than in previous models. Notice in the picture below how the old RX design had more deflex built in versus the HPX, which was and has been a very successful bow.

 

Why more delfex now then? Back to the beginning of what the modern riser design is mostly based on, the Hoyt GM TD2. Earl Hoyt used more deflex in his original design than anyone probably ever thought of without notice. The following decades gave way to very similar geometry with very slight differences. The more modern times with technology has introduced risers with less deflex making for quicker bows.

 

 

Whether you are new to archery or an expert with decades of shooting skills, the more deflex designs offer more accuracy regardless of brand. Shoot a less deflex riser well and the more deflex risers will help make you even more accurate.

 

 

If you don’t understand how brace height affects the arrow, then don’t feel alone.

 

There are two types of brace height. No not high and low.

 

The first type I call “Natural Brace Height”. This is the bows natural brace height based on the geometry of the riser design, is it reflex or deflex in design. As stated before a reflex design will have a lower brace height and a deflex design will be higher. Given the same limbs and length of string with the same number of twists, you would see this naturally happening. This is why I call it the Natural Brace Height. You can achieve the same brace height for each design by making the string longer or shorter when made or changing the number of twists.

 

The second type of brace height is what I simply call, “Adjusted”. By changing the string length as stated above, you can adjust the brace height for either design of riser to be the same.

 

So why the fuss with two designs, reflex or deflex, if you can “adjust” the brace height from its natural location?

 

If the riser has more deflex design then the natural brace height will be higher. Remember the higher the brace height the slower the arrow, but the more stable and more forgiving it will be. A riser with less deflex with a natural brace height being lower will be faster and not as forgiving. You can change the brace height by adjusting it, but you are changing the natural nature of the bow.

 

 

Let’s say that the less deflex riser naturally rests at 8.5” of brace height and the more deflex riser naturally rests at 9.0” brace height. Just as an example without adjusting anything, you can see that the more deflex riser is already closer to a more forgiving setup without any adjustment yet. By adjusting the less deflex riser and bringing the brace height up to 9.0” we have to shorted the string via twists if possible. This increase in brace height will affect the arrow spine some and stiffen it. To go up to 9.25” of brace height we will drastically change the arrow flight and tune, where the more deflex riser will be naturally closer to the 9.25” of brace height with only a few twists. This allows us to keep the spine much closer for tuning and still give even more forgiveness without being far from the natural design of the bow.

 

Forgiveness is a term used lightly and nothing makes it truly more forgiving, but what it does refer to is a more forgiving bow is purely just a more stable and accurate bow.

 

While a higher brace height is a tad slower, it is however more stable. The idea is to introduce more deflex into a riser so that the bow is more stable.

 

So what do you know now? You know that a reflex design is faster at the cost of accuracy because the bow naturally is not as stable. You know that a deflex design is slower at the cost of more accuracy because it is more stable.

 

Want to see the proof? Over the past year or so you started to see some changes in what risers are being used. Take a look at some top archers and you will notice that more and more Hoyt GMX risers are being used. The Hoyt GMX is an ILF riser with more deflex geometry built into it. You will also start seeing a lot more Hoyt Prodigy RX risers being used which also have more deflex built into it. Both risers use Earl Hoyts original geometry dating back to the TD2 over 30 years ago. Win & Win already use a more deflex design and have had their success stories as well, but keep in mind that they stuck with their geometry for the most part for all of these years.

 

The simple truth is that more deflex to equal a natural 9” brace height is still the way to go to achieve a bow that is more stable and accurate. Technology is moving forward only to find that old designs are more in tune than we ever imagined.

Hoyt Formula RX and Hoyt GMX (Old deflex geometry, just like the TD4)

 

So the next time you are shopping for a new riser or bow, you will now have one more thing to think about before pulling the trigger. It better be an accurate decision.

 




Tony Brasher
Tony Brasher

Author



4 Responses

Paul norbury
Paul norbury

January 29, 2017

You are spot on .i have noticed fellow archers going back to there Hoyt gms and getting higher scores .and notice how gm risers in good condition are going up in value.paul norbury

Philip
Philip

January 22, 2017

Good article, well structured and well broken down, I enjoyed it and thank you for the value you bring.

I’ve checked out the other articles as well and I really enjoy them, keep them coming!

Kind regards,
Philip

http://buyarcherybows.com/

John Buckley
John Buckley

September 14, 2016

Great article. You propose more prodigy RX will be used due to a return to a more deflex design. Today Hoyt just told me the opposite the new Prodigy RX,is designed to be more reflex to gain speed about 3-5 fps so I don’t understand you closing conclusions,something is wrong or have I not understood part of you closing comments ?

James Hallows
James Hallows

March 10, 2016

Great article – thanks, but just to let you know the image links seem to be all broken.

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