Byron Ferguson and brace height tuning

[SELFBOW19953]

[NothingHappenedToday]

SELFBOW19953  -- I think that the "why" does matter, at least so me. I don't want to just randomly increase or decrease my brace height and hope that I stumble upon the right string length for my setup. If my arrow is slightly stiff, I'd like to know if I'm better off increasing or decreasing my brace height. Plus, I just find the mechanics and physics of this hobby fascinating.

[Caughtandhobble]

NothingHappenedToday-
Thanks for a great thread, sometimes the simplicity of traditional archery is not that simple. A few years ago I saw a similar thread on another site and it was pretty much divided down the middle on opinions. Through my trials and errors have to stand firm on my beliefs.

Go out and play with your set-up and see what works best for you. After you do, please report back on your individual findings. From looking at your avatar it looks like you have great form and should be able to come to your own conclusion.

[Mo0se]

If you actually spend time testing it, you'd know the answer       Think of brace height as preload on your limbs, the higher the brace, the more preload on the limbs transmitted to the arrow. The lower the brace the less preload you have.

You shorten the power stroke when increasing brace height, and lengthen it with a low brace height. Think of it as horsepower, the more stress you put in the limbs, the more initial power you have, but because the string is now shorter, you have taken away some of the limbs travel at the end of the stroke.

Lower brace heights are faster because the entire power stroke is longer. Higher brace heights are slower because the string is shorter.

[stonewall]

I adjust my brace for quieter and the beat feel. Maybe the editor got the phrase wrong in the book. It does happen

[katman]

Lets not forget the change of arrow angle when changing brace height. Lowering brace in effect moves arrow further from center shot at window(points further left for RH shooter) so it shoots stiffer. Raising brace moves arrow closer to center shot at sight window(points more towards target), shoots weaker. Also agree raising brace increases poundage and makes arrow shoot weaker, at least for me. Clear as mud now.  

Either way the effect is very small and may help with extra fine tuning, like trimming or moving out a string silencer makes arrow shoot weaker, etc.

[Clint B.]

I copied this passage from Easton's Tuning Manual:

"For recurve bows, another way of altering arrow spine is with the brace height. By increasing or decreasing the distance from the bowstring to the pivot point of the grip, the dynamic spine of the arrow can be made slightly weaker or stiffer. Increasing brace height will make the arrow shoot weaker, and decreasing brace height will make the arrow shoot stiffer."

[katman]

So Mr. Ferguson's book and Easton's manual contradict one another? Hmmmm.

I will set the bow up and stay within the bowyers recommended brace heights for max efficiency. Prefer to tune arrow and centershot for tune on a non ILf bow.

[mgf]

Caughtandhobble is correct. It's not about the poundage or the power stroke. It's about the angle of the arrow to the riser. The closer the nock gets to the riser the more acute the angle to the left (for a right handed shooter).

Therefor, increasing the brace height makes an arrow act weaker...a lower angle when the arrow leaves the string.

Try it for yourself. Opinion doesn't have anything to do with it. Byron is wrong.

[shedhunta]

Its the angle.  Somewhere on this website there is a good picture describing brace height and the arrow angle as it leaves the bow.  I will try and find it.  This is more dramatic on bows not cut close to center.

[The Whittler]

I know what works for me. When I started trad. over 25yr ago I was told if your arrows are shooting straight but are going to the left some you raise your BH up until your arrows start to come back to center. This is for a right hand shooter.

 This has worked for me ever since.

[NothingHappenedToday]

Maybe both are correct? So, since changing brace height changes the angle of the arrow on a non-centershot bow, then there's no angle to change on a centershot bow. Therefore, INCREASING brace height on a centershot bow will stiffen the arrow (shorten powerstroke/transfer less energy to the arrow), but will weaken the arrow on a shy-of-center bow (change angle of arrow more towards center).

[Mark R]

I think somewhere this got off track, you want your bow to shoot at its best for you, sure you need a good starting point,most of the spine charts are a good place to start, the bowyers suggested brace height should be followed,  then find an appropriate arrow using the spine chart,then you should find the (sweet spot) on your bow, different arrows have different sweet spots they all have one,this could take some time and experimenting with brace height but should not be much, in the end you find what works best for you,nothing is a given. To say one way works best for all is misleading, the bow will tell you what it wants. Different bow designs, three fingers under,split finger,draw length, rest and plate material, and type of string all play a part. Generally speaking match the arrow to the bow set up and not the bow to the arrow, and kiss, arrows are cheaper than bows.

[**DONOTDELETE**]

I'm with Mark here totally on this issue.

I wouldn't recommend changing the brace height on your bow to tune arrows at all....

Yes it can effect the arrow spine a little bit, and on bows with the shelf cut "Before center" or even cut "To-center" changing brace  will have more effect on point of impact windage.....

But it also has an effect on the bows efficiency, how quiet it is, and the amount of vibration.

Every bow has an optimum brace height where the string is at it's peak tension level. That's where you want it to stay. Its always best to tune your arrows to your bow after finding the sweet spot in the brace.

Changing strike plate material density, and thickness is another way to fine tune an arrow to the bow.....If that doesn't work you need to consider different spine arrows...... My .02 cents worth...

[Clint B.]

Let's say you're out roving on a warm day with your bow with a relatively new Dacron string.  As the day wears on, the string stretches and the brace height lowers. What is the effect on your arrow flight?

[Orion]

Would have the effect of weakening the dynamic arrow spine little, but probably not enough to notice in how the arrow flies.  As I pointed out in my initial post, small changes in brace height that some folks use to tune are really small.  They yield very small results. Some folks say they can detect these results.  Most can't, IMO.

Really not something to get one's undies in a bundle about.  I tend to do what Kirkill does, i.e.  manipulate brace height to find the sweet spot and do any additional tuning with point weight, arrow length and side plate thickness. Of course, the sweet spot itself is also influenced by arrow length, weight and weight distribution, amount of centershot, etc.

[Clint B.]

I'm not too precise. I check my brace height with my palm and outstretched thumb.  

[Smallwood]

My own findings show an increase in bh weakens arrow spine, and decrease stiffens spine.
Best thing to do is test it for yourself...drop your bh to the lowest recommended and shoot a group. then crank it up to the highest recommended bh and shoot a group. What are Your results?

[**DONOTDELETE**]

Originally posted by Smallwood:
My own findings show an increase in bh weakens arrow spine, and decrease stiffens spine.
Best thing to do is test it for yourself...drop your bh to the lowest recommended and shoot a group. then crank it up to the highest recommended bh and shoot a group. What are Your results?

Exactly.     ... How hard is that to do? And while you are slowly changing your brace height, pay attention to how the bow feels in your hand after you drop the string...and when it becomes the most quiet....You'll find it's both at the same brace height and that IS the sweet spot. It  will also give you the best performance at that brace...

Then ya leave the dad burn thing alone, and tune your dad burn arrows, or adjust your strike a bit...

[olddogrib]

With all due respect to Byron, raising the brace height will weaken dynamic spine and vice versa. This question probably wins the award across archery forums as most debated topic...and the responses are always about 50/50, lol!  Which tells you something else...if our form was perfect enough, we wouldn't have to ask and could all agree.  The rest are just guessing, lol.  Not a criticism, I certainly had to research it.  Somewhere there's a PhD dissertation on it.  Turns out the logical power stroke argument loses.  If I remember correctly, it's the fact that a low brace height keeps the nock on the string slightly longer affecting paradox and biasing the path of arrow travel back to the left (RH shooter).  Don't blame me, I didn't dream it up...but I did stay at a Holiday Inn Express last night.  The downside, if you were counting on a few twists (untwists) to solve all your tuning woes...probably not going to happen!  Most can recognize crappy arrow flight and it's a bigger problem than BH adjustment.