Brace height

[Schme1440]

Originally Posted by buzz lite beer

for example hold a pen or pencil loosely between the first joint of your right hand index finger and the thumb, place your left hand index finger on a table and rest the end of the pencil on it, slowly push the pencil forward keeping the tip of your R/H index finger on the surface of the table as you do so, result:- the tip of the pencil drops down toward the table top.

IMO the change in BH is not enough to effect the tune of your setup. If you worried about things like that all the time yu would never have time to shoot as you would be tuning all the time.

[buzz lite beer]

Getting the little things right including brace height could make.

Originally Posted by Schme1440

This years Plans.

1 Attain a 900 Albion (Back to what I was shooting before I moved to compound)
2 Attain a 1200 FITA (Same as above)
3 Attain highest average over summer Outdoor Essex Albion League(missed out by 8 points last year)
4 Attain MB status (Same as 1+2)

Most of my goals aim to get back to where I was just after left the GB junior Team and moved upto Senior. 3 is to settle a score with myself and attain No.1 Rank in our summer leauge. I have never made it before even though my avereage has been well above the rest purely because I missed one of the shoots.

a little easier. Simon Needham is famously quoted if I run my brace height right I get 590 Portsmouth run it 1/4" lower I get 575 Portsmouth.

[Schme1440]

Originally Posted by buzz lite beer

Getting the little things right including brace height could make.
a little easier. Simon Needham is famously quoted if I run my brace height right I get 590 Portsmouth run it 1/4" lower I get 575 Portsmouth.

I never notice big differences with my BH. I will check it once in a while but I dont notice much difference. I will be playing with it tonight and will be keeping a closer eye on it in the future. Hoepfully I can get the bow shooting ove 200fps with just altering the BH. Maybe I should put a little twist on the limb bolts to increase the weight? I jsut feel hitting that 200fps will help my longer distances and correcting the BH and a little on the limbs will help that.

[Murray]

wrong route IMO to maximise fps using brace height. You should look to minimise group size with brace height, nothing else.

[Schme1440]

Originally Posted by Murray

wrong route IMO to maximise fps using brace height. You should look to minimise group size with brace height, nothing else.

Good point. Plan for tonight. Lower BH about 1/4 inch. Increase draw weight by about 1#. Hoepfully the combination of this will give better or at least same groupings and more speed.

[Rik]

I did some testing once on BH and arrow speed. Got an increase of about 7fps, by dropping the BH by about 1.5cm. That's a lot of BH change for a relatively small gain.
(38lb limbs, 66inch bow, BH 22.2cm down to 20.7, lowest speeds up from 203 to 210fps).

I don't know how low you need to go before you see problems with the limbs. I know that I saw problems with the arrows, one time, when I didn't notice that my BH had dropped below 20.5cm. It's difficult to miss symptoms like the nocks pulling out and ending up halfway down the range...

I've seen suggestions before that you can tune the BH by measuring the arrow speed. I don't believe it. You just end up with a low BH that way - the range of speeds, the accuracy of the measuring equipment and the variations due to the archer would rule out being able to see the "sweet-spot" in the BH by that method (for most people - there may be some lucky individuals who could get results that way).

[WhitehartFB]

I have to agree the bracing height is a piece of the puzzle to getting the bow working for you. Since coming back to the sport I have been shooting my bow at my old BH measurement and have never really worried that there might be a better BH position as the bow shoots as I want it to and I was confident that I have it set up fine, however this winter I spent a day just checking things over at 20yrds on a portsmouth face and starting at the top of the BH range moving down gradually (twist at a time ) to the lowest I could physically see the points where the groups open close open close and open again. Also where the groups were the smallest the arrow speed also increased.

There were two points where the bracing height gave better groups one near the top(1) of the range and one near the bottom(2) at point 1 - I was getting around 1-2fps more and at point 2 - 4-5fps compared to the other settings and the bow was noticebly quieter as I expected. The results showed that I had it right for me all the time - well at least I now know.

For reference I have it set at the higher end, the bow design does not allow for a great cut away sight window so the helps with arrow clearance. Still 214fps 41lb on fingers sight all the way out at 90M/100yrds I'm happy.

A tell tale sign if your BH is too low is that when you shoot your bow you will hear a crack rather than a nice boom from your bow this is the sound of the string slapping the limbs. Also look at the profile of the limbs they should at least have a slight curve rather than being flat at points along the limb (especially the middle part).

[joetapley]

Originally Posted by Whitehart

Also where the groups were the smallest the arrow speed also increased.

This is a bit of an illusion. Measured arrow speed is not the arrow linear speed but the time of travel of the arrow point between two planes. Measured speed out of the bow can be up to 2fps say below the actual speed. The better the tuning the nearer the measured speed is to the actual speed.

This phenomenon has been used for fine tuning button spring pressure.

[WhitehartFB]

Originally Posted by joetapley

This is a bit of an illusion. Measured arrow speed is not the arrow linear speed but the time of travel of the arrow point between two planes. Measured speed out of the bow can be up to 2fps say below the actual speed. The better the tuning the nearer the measured speed is to the actual speed.

This phenomenon has been used for fine tuning button spring pressure.

Understand what you are saying and yes if the arrows wobbles to the target the measurement is useless due to the drag factor, but the measurement (which was done out of interest rather than as a tuning tool and taken at 5m from the bow) was clearly detectable and shows a corrolation between BH and arrow speed however small it may be. Whether below GMB it's of any use who knows.

[Schme1440]

BH lowered about 1/4 inch. Bow is little noisey now. String looks at its limit so new slightly longer string is in order I think. Increased draw weight by 1 pound. Spped increased to 199fps. Grouping seemed ok. Was able to consistantly shoot groups. More shooting needed to determine any advantage. I think its down to the string which does seem a little short and well worn.