Here's a little thought does brace height really effect how the bow shoots, or is it more a case of a noisy bow distracts you from your shot and the anticipation of the noise is enough to make you tense up?
I don't know the answer all I do know is I like my bow to be as quiet as possible and this seems to help with my groups. Changing the brace height will only alter the tension on the string at rest not at full draw, so it can be compared to tuning a guitar string by increasing or decreasing the tension on it and therefore it's 'tune'. I find that is the brace height is too low I get a 'buzzing' sound from the bow, which I think is the top and bottom of the string vibrating against the limbs, if the brace height is too high the bow seems to make more of a 'thunk' or 'slap' and this I think is down to the tension on the string being so high that the limbs are almost pulled to a stop. At the 'best' brace height for me (about 9.25 inches) the bow 'thrums' and just feels nice to shoot.
The other problem I have is how people say brace height effects groups, other than what I have said about being distracted by a noisy bow I cannot see the vibration of the string effecting the arrow. After release you get the power stroke as the string pushes the arrow forward this whole movement from the release point until the string reaches it brace height again is part of one oscillation (so at this point the only vibration will from a poor release see a little release in the snow), the string will continue past the it's brace height and as it does will start to slow down at which point the arrow will leave the string and from watching high speed videos of releases it would seem that the arrow leaves the bow before the string has started it's return journey, so again I wonder if the only effect the brace height has on the shot is the anticipation of the noise. Of course changing the brace height will slightly alter the nocking height and this will have a small effect on the arrows flight.
Your style is so unique compared to other people I've read stuff from. I appreciate you for posting when you have the opportunity, Guess I will just book mark this blog.
ReplyDeleteAlso visit my web blog - best online education service
Part of the attraction of the Revolution was how quiet my "rig" became, and that has been commented on by other users here and elsewhere, too.
DeleteHowever, of late I had become lazy with checking the bracing height when I set up: didn't seem to affect my accuracy or lack of too much, or not so I'd notice.
BUT what was beginning to irritate was that I was realising that the bow was becoming "buzzy", and I'd check the tightness of the various appendages, and put it down to the clicker on this bow (plate on plate...), so I put a rubber pad on the strike plate and that made a little difference.
However, yesterday, when putting some new ACE arrows through a chronometer/chronograph, I checked the brace height and found it low at 8", and I moved it to 8.75"...and what a difference to the enjoyment of the bow...SOOOO quiet again. Lesson learnt, don't be lazy.....( on a 70" bow, I probably need to bring the height out to 9"?)
...have now moved it to 9"...yum!!
DeleteI am currently shooting at about 9 5/8".
Delete.
WOW! I will move tomorrow night to 9" I measured today, thinking it was 9" but not quite......
ReplyDelete(I hope this reads ok???)
Bought my revolution last Thursday, my very first bow and love it, however it does buzz a little on shooting, certainly doesn't seem to be the super quiet bow I'd read about. Taking it back to the shop on Saturday to discuss bracing height as I'm hoping this will sweeten up my new pride and joy!
ReplyDeleteNice to find a site dedicated to this bow, such an awesome bit of kit and so little information about it online!
Mike
Oh and also try taking everything off the bow to eliminate a loose part on the sight or stabs making a noise.
DeleteHi Mike welcome to the blog.
ReplyDeleteWhich limbs and brace height are you using at the moment?
As has been mentioned here the Revolution needs quite a high one, I am currently shooting with my brace hieght at 9.5 ". If your is much lower ( half an inch is a lot for brace height) then I would add two or three twists, shoot three arrows (first one will make sure limbs are settled again), then repeat until you find a sweet spot. It is a lot like tuning an instrument you can keep adding and adding thinking this is not helping and then suddenly you find that spot the works.
Thanks for the welcome Tony, currently shooting 30lb SF Axiom limbs for a 66" bow.
ReplyDeleteI identified the source of much of the vibration when a nylon bush fell out of my sight! This has now been replaced and is shooting much quieter
Where do you measure brace height to? Measuring to the back edge of the riser I'm at around 195mm which is around 7.75". From the deepest part of the grip this is probably closer to 7.25". I'll have a play next time I'm at the range!.
Thanks for your advice.
Mike
Mike, you should be measuring your brace height from the deepest part of the grip (the throat of the bow). Most people find that the revolution tunes nicely around 8.5-9.5 inches.
DeleteHi Tony.
DeleteJust got my revo, not shot it yet, still setting it up.
I shoot a 66" bow. The leaflet it came with states 7.5 - 8.5 for a 66 er.
Got it at 8" at the moment.
Put some 36lb winnex limbs & a Spigarelli sight.
Hoping to have it running smoothly for this seasons Frostbite.
Thanks for the Blog.
Gary
Sounds like a nice setup, please come back and let us know how you get on, particularly with the brace height. I would recommend at least exploring the higher heights. Have fun
DeleteTony G
Been playing around with brace height on my Spig Revo so thought I'd see what others were saying out there. Came across Tony G's post and wanted to comment on how BH can have an effect on grouping size. If you make a significant change in BH you need to go back and check your overall tune. A big increase in BH will likely cause your arrows to show weak (changes the dynamic spine of the arrow, probably due to the longer distance between the string and the plunger at the time the nock leaves the string - at least that's the explanation I've read that makes sense since the change in DW is very little). To support this with hard data, I went from a brace height of 8 1/2" (what turns out to be the lower 'sweet spot' for my 70" SF Carbon Elites, drawing about 34# otf, 29" DL) to a higher sweet spot of 9 3/16". This increase of 11/16" caused about a 0.25 pound increase in DW (probably about the range of error for the digital fish / bow scale I have), but my bareshafts went from hitting 3-4" right of my fletched group to 14-16" right at 18m, and my fletched groups spread out significantly.
ReplyDeleteAfter cutting 1/4" off my arrow shafts, backing my limb bolts off 3/4 turn, and doing some fine tuning with my plunger tension my bareshafts are hitting in the fletched group, and my fletched groups are tightened back up again.
Smaller changes in BH might only require plunger spring tension adjustment to tighten group size due to the change in dynamic pine.
Also remember that changing BH changes the height of your nocking point, so that can contribute to things not being in perfect tune (and thus larger groups / lower scores) if you forget to re-position your nock set(s) after changing BH.
After this experience I will always go back through the full tuning process after any change in BH (or changes to anythings else for that matter - everything is interconnected in how the bow transfers energy to the arrow). Luckily I'm shooting barebow so I don't have as many different "moving parts" that can impact that perfect tune! :-)
Thanks for the blog Tony G.
-A
Hi Aisis,
DeleteThanks for the contribution, it is interesting that changing your brace height had such an effect on you arrows. I have always tuned the bow so it shoots quietly and then looked at what spine I would need and so far have never needed to then change my brace height more than 1/4" and so have never encountered this before.