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Main Boards => PowWow => Topic started by: widow sax on October 23, 2011, 04:03:00 AM

Title: Brace height and its affects on speed
Post by: widow sax on October 23, 2011, 04:03:00 AM
I got a new to me acs longbow. I deceided to check what affects changes in brace height has on speed. First let me say I have posted that I believe it does not have a affect on speed so I thought I would back up my words with results. I have a very consistent form, draw and release I usually only very one fps high or low so the results schould be accurate. I have worked with this bow some and I am using a brace height of 7" so I will start lower then this and move up 10 twist at a time untill I go over one inch past starting point and then go back to my 7" were I will keep this bow. I used three different arrow weights let me know what you think and any thoughts about the results. This is a 12" riser 58" bow 45@28" bow I draw 26.5 usualy but with this lower lbs may be 27".  

6 13/16 brace height

387gr 182fps 452gr 177fps 517gr 166fps

7 1/16 brace height

387gr 182fps 452gr 175fps 517gr 165fps

7 5/16 brace height

387gr 182fps 452gr 174fps 517gr 165fps

7 5/8 brace height

387gr 182fps 452gr 174fps 517gr 165fps

7 15/16 brace height

387gr 180fps 452gr 174fps 517gr 163fps

I then went back to my 7" brace height.

387gr 185fps 452gr 178fps 517gr 167fps

I then deceided while I have the crony setup I would check the difference with a hold at full draw and release and the way I shoot a pull threw release. I used one arrow for this it was the 452gr arrow.

Hold and release 174fps

Pull threw release 178fps

So what do you think about the results!

I think I found the correct height for this bow and I will keep it a 7"!

As I thought untill you get a good bit over it does not have any real affect on speed. Widow
Title: Re: Brace height and its affects on speed
Post by: Benny Nganabbarru on October 23, 2011, 05:58:00 AM
Thanks for posting your testing! Interesting stuff, and food for thought... To be honest, I have never been much of a tinkerer with brace height, and approximately the recommended one is always good enough for me, being unable to tell the difference (not counting some of my learning episodes of either way too low or way too high).
Title: Re: Brace height and its affects on speed
Post by: john gerrard on October 23, 2011, 06:41:00 AM
Thank you for posting,very interesting. I am another one who only tinkers a little with brace height. I work mostly for quietness. Brokenwing
Title: Re: Brace height and its affects on speed
Post by: Joe Subler on October 23, 2011, 06:57:00 AM
Widow,  did you take much note about any sound difference at the various brace heights?

Joe
Title: Re: Brace height and its affects on speed
Post by: Flingblade on October 23, 2011, 09:04:00 AM
Nice to know.  I recently padded the ends of my string with wool yarn to quiet my Black Widow PSA and it changed the brace height from 8 1/2" to 9" which is the top of the bowyers recommended brace height.  I liked the way it shot at 9 better so I left it but soon found that the arrows I was shooting were overspined as most shots were well to the left.  I switched from Arrow Dynamics traditionals to the trad lites and they fly great.  Did you notice any difference in how the arrows flew at different brace heights?
Title: Re: Brace height and its affects on speed
Post by: Maxx Black on October 23, 2011, 09:56:00 AM
Thank You for taking the time to check this and then record for us . I find it interesting as I'm always tinkering as well but without really knowing the speed changes.(mostly trying to quiet the bow). That amount of speed changes(lack there of) makes me feel better when I'm playing around. Maxx
Title: Re: Brace height and its affects on speed
Post by: Rob DiStefano on October 23, 2011, 10:10:00 AM
i think that, with trad typical hunting distances in mind (10-20 yards or so), the difference between 163fps and 178fps is nearly meaningless.  i take that back - it is meaningless.

what's most important to me is not dialing in the fastest arrow speed for a particular bow, it's finding the best "stability" for a bow and its arrow.  there is a brace height *range* (not just one specific brace height) that will allow for the bow's best stability with me pulling its string.
Title: Re: Brace height and its affects on speed
Post by: Swamp Yankee on October 23, 2011, 10:13:00 AM
Interesting, but for a max difference of 5fps, I'd be looking for quiet over speed.
Title: Re: Brace height and its affects on speed
Post by: **DONOTDELETE** on October 23, 2011, 10:29:00 AM
That tells me you have a pretty nice set of limbs on your bow with good preload. That... and long bows are a bit more forgiving to different brace heights until you get real low. but testing down to 5" isn't practical or she'd be biting your wrist.

Different bows with different limb designs are going to test differently too. Some recurve limbs are a lot more sensitive to brace height. You may not see a huge jump in speed, but noise and vibration is where you'll notice most the difference.


each bow design has a sweet spot where the tension of the string stops the tips clean with the least vibration.
Title: Re: Brace height and its affects on speed
Post by: Rob DiStefano on October 23, 2011, 10:31:00 AM
QuoteOriginally posted by Kirkll:
That tells me you have a pretty nice set of limbs on your bow with good preload. That... and long bows are a bit more forgiving to different brace heights until you get real low. but testing down to 5" isn't practical or she'd be biting your wrist.

Different bows with different limb designs are going to test differently too. Some recurve limbs are a lot more sensitive to brace height. You may not see a huge jump in speed, but noise and vibration is where you'll notice most the difference.


each bow design has a sweet spot where the tension of the string stops the tips clean with the least vibration.
well said, sir - and right on the money.
Title: Re: Brace height and its affects on speed
Post by: jhg on October 23, 2011, 10:38:00 AM
QuoteOriginally posted by Rob DiStefano:
...it's finding the best "stability" for a bow and its arrow.  there is a brace height *range* (not just one specific brace height) that will allow for the bow's best stability with me pulling its string.
I agree with Rob on this one, but its always worth the effort to explore and experiment. There is nothing wrong with finding within that stability and quiet the sweetest performance your tackle can deliver, whether an extra FPS or 20. Numbers do tell us something. Its worth knowing what they are, even if in the larger context of trad hunting where skill, both woods wise and at the shot, are paramount. But we all know that already anyway ;0)

Joshua
Title: Re: Brace height and its affects on speed
Post by: widow sax on October 23, 2011, 11:00:00 AM
Yes I was checking how the bow felt and sounded with the lower brace height when I untristed the string the beaver balls also untwisted and made a vibrating or buzzing sound and the string seamed to feel that way also. I have found if you do not get beaver balls tight they make a buzzing sound as the string vibrates against the leather inside. AS I twinsted up the string the balls got tingter aroung and that noise went away. I was shooting close so I could not tell any small change in arrow flight but there was a change from the lowest to the hightest in the way they stuck into the target. There was a difference in the sound from the arrow weight but you would expect the lighter one made the most noise and the heaver one made the least. I did not use a crony to come up with the seven inch brace I just shot it after and found I liked 7" the best I got lucky that it was also the fastest for some reasion. The only thing I need to do in make up my mind what weight arrow I will shoot I would like to shoot around 170fps to 172fps as I am use to that trajectory. I know a few fps won't make that big of a difference in that I am going to try to get close to 500grs that schould work for me with this bow I also did a little math and found that this bows speed changes 1.3fps to 1.34fps for every 5gr of arrow weight. I may try this with one of my widows somedsy but I did not want to mess with them now because I am hunting with them. Thanks for you imput guys.   Widow
Title: Re: Brace height and its affects on speed
Post by: widow sax on October 23, 2011, 11:05:00 AM
Sorry about all the missspelled words I was typing fast and did not proofread it enough I guess O and buy the way I can't spell worth a lick anyways LOL.   Widow
Title: Re: Brace height and its affects on speed
Post by: widow sax on October 23, 2011, 11:55:00 AM
(i think that, with trad typical hunting distances in mind (10-20 yards or so), the difference between 163fps and 178fps is nearly meaningless. i take that back - it is meaningless.)

I personaly believe that if I'm putting the effort of pulling the bow then I schould get the most out of the bow for that effort but not at the expence of making the bow shoot bad. It still has to be stable and all the other things that make it a good shooter. I think my findings kind of point out that there is a range and in that range the speed does not change that much so you can find were your bow works good and you do not have to worry about its affect on speed because it realy does not affect it. That is what I was trying to prove because I always heard people saying that lower is faster and higher is slower I always set the bow up to were I liked it and never worried about it but believed it did not have a big affect on the speed. I do not think any infomation is bad you take from it what you want and use it however you want. I happen to love the tec side of things and always will I like to tinker and see its affect be it in speed, arrow flight or how the bow reacts thats what I injoy doing and sometimes post it for all to see. The word speed in now a bad word in the trad comunity it is just one of the many componets that make a good shooting and performing bow there is lots of others and I'm not saying it is the most important one either it is just another measurement.    Widow
Title: Re: Brace height and its affects on speed
Post by: Javi on October 23, 2011, 12:13:00 PM
Now repeat the test going down to 6" and see if you get the same results..

Note: I've done almost the same tests with very different results.. a 49lb@28 1/2" mild R/D longbow shooting a 658 grain arrow.. difference between 7 7/8" and 7 1/4" was 14fps.. above 7 7/8" showed no effect... under 7 1/4" speed fell off slightly.

It's fun to play with stuff....  :goldtooth:
Title: Re: Brace height and its affects on speed
Post by: widow sax on October 23, 2011, 12:34:00 PM
That is amazing good for you. I could not go to much lower because I had a short 6 strand skinny string on the bow that I had on hand. I'm not shure I would want to go lower anyways I would hit my arm I have womans elbow it bends inward and I would not like the way the bow felt either even if it did go faster.I could put the string that came with it on and go lower I may do that when I get time after all it is hunting seasion LOL not that I'm seeing much to hunt. I am still playing around with the two strings but with the string that came with it i liked 7" also.    Widow
Title: Re: Brace height and its affects on speed
Post by: Sixby on October 23, 2011, 01:08:00 PM
I agree with both Rob and Kirk on this one. However in my opinion 5 fps is vry significant in that it basicaly represents 5 lb of draw weight to lose that much speed.

It becomes even more important when we are talking about building efficeint short draw bows for those that are already being challenged performance wise or for those that want the most performance out of an extremely heavy arrow for large or dangerous game.

However a good quiet bow of basicaly any shootable speed is suitable for close range shooting at deer size animals.

That said I will always pick a fast , quiet bow over a slow quiet bow. I also will not own a bow I have to put over one set of silencers on to make it quiet with a hunting weight arrow. 9 gpi or better./

God bless you all, Steve

God bless you all, Steve
Title: Re: Brace height and its affects on speed
Post by: Rob DiStefano on October 23, 2011, 01:19:00 PM
i hear you, steve, about the fps/holding weight thing.  however, i will always take "stability" over *added* fps/holding weight, because "stability" allows consistency.  i think most of us know how fast bows aren't necessarily the most consistent/accurate bows.  to get the most outta yer gear, one DOES need to put in the efforts ...
Title: Re: Brace height and its affects on speed
Post by: **DONOTDELETE** on October 23, 2011, 04:53:00 PM
QuoteOriginally posted by Rob DiStefano:
[qb]      i think most of us know how fast bows aren'y necessarily the most consistent/accurate bows.    
I'm real curious why you would make that statement Rob?  

I understand that generally most of the "Fast" bows you see out there the guys are using ultra light arrows...and light weight arrows are real sensitive to a poor release vs heavier shafts.

but is this the reflection of the archer, not the bow. To say most fast bows are unstable, would be like saying most fast cars are unstable. There are bows out there that cast heavy shafts at impressive speeds that are rock solid in the stability dept.

What difference does this extra speed and extra power in the bow mean to a hunter that shoots 10-20 yards?

Flat trajectory for threading the needle, or missing that branch....

and.... getting that extra power at a lighter draw weight is icing on the cake for when that less than perfect shot hits a shoulder....

Seems to me.... a guy might like those qualities in a bow.
Title: Re: Brace height and its affects on speed
Post by: Rob DiStefano on October 23, 2011, 05:38:00 PM
QuoteOriginally posted by Kirkll:
 
QuoteOriginally posted by Rob DiStefano:
[qb]      i think most of us know how fast bows aren't necessarily the most consistent/accurate bows.    
I'm real curious why you would make that statement Rob?  ... [/b]
didn't say all bows, but *some* bows can be incredibly fast - maybe even by 15/20fps - but at those speeds they may have no stability/consistency, which affects accuracy.  

having such a bow, what would you opt for, speed or stability - or sell it and get a bigfoot?  :D
Title: Re: Brace height and its affects on speed
Post by: Javi on October 23, 2011, 06:35:00 PM
I opt for getting the most performance available out of my bow... performance to me means... the most accurate, most forgiving, quietest and the fastest possible with an arrow of sufficient mass for my intended prey.  It isn't about just one factor, but a synergy of all the factors and I don't want to leave anything on the table because of preconceived notions.
Title: Re: Brace height and its affects on speed
Post by: Sixby on October 23, 2011, 06:41:00 PM
AMENNNNNNNNNNNNN Mike!!!!! Thats the right answer.
Why should anyone have to make excuses when there are so many really great bows to be had?
God bless you all, Steve
Title: Re: Brace height and its affects on speed
Post by: **DONOTDELETE** on October 23, 2011, 08:31:00 PM
Quote
didn't say all bows, but *some* bows can be incredibly fast - maybe even by 15/20fps - but at those speeds they may have no stability/consistency, which affects accuracy.  

having such a bow, what would you opt for, speed or stability - or sell it and get a bigfoot?   :D  [/QB][/quote]i do not understand why you would think that a bow shooting a respectful hunting weight arrow of say 500 grains at 160 fps would be more stable than a bow shooting the same weight arrow at 180 FPS.

i think this "stability/consistency" thing you are referring to here is what has me going.

let me ask you something.... If you have a bow that you really like a lot and shoot pretty darn good with at 10 -20 yards,  and someone handed you a bow that shot as smooth or smoother
than yours did, was noticeably faster, and you could shoot a much flatter trajectory clear out to 30 yards with it.... Wouldn't that raise your eyebrow some?

Now if that faster, very smooth shooting bow happened to be an Eagle Wing, you were probably standing next to Steve.

if it was a "Tornado", you were probably standing next to Mike Rash.

If your feathers went up in flames, it was most likely a Sasquatch the guy handed you....    :biglaugh:    :biglaugh:  

i wouldn't sell my bow and buy a Big Foot bow at all. You have to have slower arrows on those high fire danger days.   :biglaugh:
Title: Re: Brace height and its affects on speed
Post by: stujay on October 23, 2011, 08:34:00 PM
Interesting test and the thoughts expressed as well, especially for those of us that love to tinker with our bows to get the most from it.
Title: Re: Brace height and its affects on speed
Post by: Rob DiStefano on October 23, 2011, 08:39:00 PM
QuoteOriginally posted by Kirkll:
 
Quotedidn't say all bows, but *some* bows can be incredibly fast - maybe even by 15/20fps - but at those speeds they may have no stability/consistency, which affects accuracy.  

having such a bow, what would you opt for, speed or stability - or sell it and get a bigfoot?     :D    [/b]
... i do not understand why you would think that a bow shooting a respectful hunting weight arrow of say 500 grains at 160 fps would be more stable than a bow shooting the same weight arrow at 180 FPS. ... [/QB]
there are limits to all bows.  experiment to find those limits, if need be.  

during experimentation with some bows, as fast or slow as they are, choosing to speed it up isn't such a good thing as stability, consistency and accuracy suffer.  each bow will have a sweet spot for each giver shooter.  that's about it.  nothing new, always been that way with stick bows of all flavors.
Title: Re: Brace height and its affects on speed
Post by: Sixby on October 23, 2011, 09:09:00 PM
Rob:during experimentation with some bows, as fast or slow as they are, choosing to speed it up isn't such a good thing as stability, consistency and accuracy suffer. each bow will have a sweet spot for each giver shooter. that's about it. nothing new, always been that way with stick bows of all flavors.

I only have one problem with this statement. Its the unspoken but insinuated belief that there has to be a compromise in stability and in consistancy and accuracy in order to have speed. Actually they all work together harmoniously in a well designed bow .

As to Kirks statement glorifying his Bigfoot in his mouth . LOL. I haven't been privledged to shoot one of Mikes bows but Kirks is proudly on its place on my rack. It is a great bow and he has every right to be proud of it. If you or anyone else sincerely believes that you have to compromise stability and accuracy and quietness to have a fast bow then you should shoot one of these bows or talk to some folks that have them. You will be pleasantly surprised.

God bless you all, Steve
Title: Re: Brace height and its affects on speed
Post by: **DONOTDELETE** on October 24, 2011, 12:28:00 AM
LOL!  Steve... a guy has gotta have a little fun now and then.... i found the idea of flaming arrows hysterical myself...

Actually Rob will have an opportunity to shoot one of my bows soon enough.

Ok Rob... I'll be completely open minded here. like Steve here, i think you can have the best of both worlds if the bow is built right, and the archer does his part....But I'm willing to experiment....

What would be a detailed explanation of the "type of stability" you are referring to? i only know of two types that effect the way a bow performs.  That is "vertical stability"  and "Torsional" which equates to limb twist and controls limb tracking.


I'd like to hear what suggestions for experimentation you would recommend regarding stability. You are no stranger to the trade.

i respect your opinions Rob. Where would you draw the lines on stability?


Note* Steve, please don't even go there on vertical stability on this thread. we've been there bro... lets save that for another day.
Title: Re: Brace height and its affects on speed
Post by: Sixby on October 24, 2011, 01:54:00 AM
Butttttttttttttttttttttttttttttttttttttttttttt,,

OK I understan, You aren't man enough for Granny Goose yet.
Title: Re: Brace height and its affects on speed
Post by: David Yukon on October 24, 2011, 02:14:00 AM
this is getting interesting...    :campfire:
Title: Re: Brace height and its affects on speed
Post by: Rob DiStefano on October 24, 2011, 06:29:00 AM
yes of course, you definitely can have the "best of both worlds", i never said that wasn't attainable.

my statement contained a logical caveat, the word "some" - i didn't say "all".  if i said "all", that would be stupid let alone dumb.     :)  

there are lotsa variables in bows, arrows, strings, and most importantly, the shooter.  fit the puzzle pieces as best as one can.  nothing new, always been that way.

HOWEVER, starting off with the advantage of a good bow design/materials *may* up the ante for the shooter, and make him/her more consistently accurate (the "stability/speed" factor).  

then again, some shooters aren't gonna be ready for a well designed bow, no matter how stable/fast it is (form, alignment, shooting flaws).  poor souls.  

so many good bows, so many variables.    :D
Title: Re: Brace height and its affects on speed
Post by: Jeff Strubberg on October 24, 2011, 09:33:00 AM
5 fps is definitely worth something to me, but frankly I am surprised the difference wasn't more significant.  Thanks for the post!
Title: Re: Brace height and its affects on speed
Post by: Tom Leemans on October 24, 2011, 10:06:00 AM
Power stroke and RPM's man. Drag racers have known this forever!
Title: Re: Brace height and its affects on speed
Post by: **DONOTDELETE** on October 24, 2011, 10:14:00 AM
Well  shoot.   :p   .. I was all ready to absorb some enlightenment as to some intricate details of balancing a bows limb stability.... and here you were just talking in general.... Hmmmm....  

i guess i need to spend more time shooting than building for awhile, and regroup.   :archer2:  


 
QuoteOriginally posted by Jeff Strubberg:
5 fps is definitely worth something to me, but frankly I am surprised the difference wasn't more significant.  Thanks for the post!
that small difference says something for the bow.
that, and it's a long bow. if you did that same test to most recurve bows from 6" to 8", you'd see a lot different results.