brace heights. a manufacturers perspective. not a mythical thumb suck.

[@vicheksink5100]

As new archer ,i love all the science behind bow anatomy and I'm very much appreciated for your explanation those issues - in human language :) I'm looking forward to come and shoot your amazing range again Sid. All the best !

[@lyrtl]

Very good Information ... thank you ... all the best Hannes / Austria

[@ludodg]

Here you have an expert explaining very! Interesting bow-technical stuff :) … and myself as an amateur-scientist with autistic tendencies getting all confused by the use of turns,twists, …-words. I’ll have to look this through more then once to be able to understand what mr Border is talking about. Vertical tension on the limb .. and then showing an horizontal movement … ? Confusing for me :)

[@Michael-pn2ye]

Love your information keep up your great work 🏹🦌

[@666mwj]

more food for thought 🙂 Being a thicko lol using the string grooves to shorten effective string length and reduce nock travel had never occurred to me! I know 'rules of thumb' can be dangerous things but would it be fair (given the huge range of risers out there, all with different ILF ranges and deflex, both of which influence the measured BH) to say that 'wind bolts fully out then in a bit (for tiller adjustment) and then set your BH so that the string leaves the limb at or very close to the end of the string groove when braced' would be a reasonable 'first approximation' to start finer tuning? Though I can see the 'massive ILF range' risers interfering with that, I'm thinking in terms of the more usual '10% adjustment' ones

[@BorderArcheryLTD]

@@666mwj that's roughly how we aim to be.

[@BorderArcheryLTD]

@@666mwj yes. The wide range adjustment risers 110 make no sense to me there is an optimal, everything else gets further and further away. That is if you know how to measure optimal. But there is so little information out there, even crap designs can't get spotted for myth and marketting

[@666mwj]

@@BorderArcheryLTD I remember when I was up a few years ago and walked away with an order for one of the very first pairs of CV9s I was privileged to spend an hour or 2 talking with your Dad (RIP) and he was less than complementary about the problems ILF can cause bowyers, not just in terms of limb angle/preload but also alignment, proper limb fit and ample scope to get it completely wrong. Border are the only company I've ever seen who take the trouble to explain, everyone else nearly always just does ''look at how brilliant our new riser / limbs are' (though I might see if I can find that '3 s' video you mentioned) so keep up the 'Master classes' Sid you're doing a cracking job of educating the hitherto appallingly uneducated 🙂

[@fotoservid]

Can you make your graphs available online?

[@BorderArcheryLTD]

@@fotoservid this graph only applies to that bow. Every bow needs its own graph, so there is little you can gain from one or two graph, other than the principal

[@stevehunt4660]

I am sure there are "bowyers" around the place getting cranky at you but from this little piece of the archery community a big thankyou for sharing your knowledge..

[@BorderArcheryLTD]

I can see it now. 2 months time I'm going to be accused of being full of hyperbole. But it will be from people with no numbers of R&D to back it up

[@BorderArcheryLTD]

We were accused of being full.of it by senior recurve engineers at a large US brand. But they adopted our 45deg carbon technology just like everyone else has. Because we are not wrong. At least not wrong yet.

[@harryvandevondervoort5695]

Dear Sid, I'm an old chap in archery. Mainly handling recurve bows for over 50 years now. Just to make sure I understand the setting of the situation : You displayed results of empirical testing on 1 specific bow setup where you showed measured values on 2 aspects of the setup referring to 4 limb bold settings and a range of brace heights. I assume the variety of the brace heights was obtained by twisting the bowstring, starting from BH 6" until you reach BH 9". Right? The 2 relevant aspects you have been measuring: 1. String tension 2. Vertical stability (nocking point deflection / 'nock travel') Nowadays, I see bows offered in riser lengths combined with limb sets mainly defined by limb fit (most ILF or HOYT Formula) Your video heading suggests disclosing news on manufacturers' justification of recommendations on BH. IN your video, you mention 'bow forgiveness' and 'risk of damaging your bow/limbs' without any reference/definition of these understandings. So, you got me confused about what you want to state with your empirically gathered data. I just don’t manage to recognize the (missing) input of the ‘bowyer’ or the suggested mythical thumb suck. Can you help me out?

[@BorderArcheryLTD]

@@harryvandevondervoort5695 if they choose the thumb suck that is sound. What string and strand count gives them thier correct sound, and what poundage. If they used the look of the bow. What looks right?? I'm not sure what is not easy to understand here. So... what do you think happens if the riser is 4" longer with the same limb exit angles??

[@harryvandevondervoort5695]

@@BorderArcheryLTD What do you exactly want to state with your empirically gathered data? For me, your reasoning sounds like beating around the bush. I don't refute your information, but I can not relate it to 'missing the input of a bowyer'.

[@davidkenyon249]

Sid, how do long draw lenghts affect any of that?

[@BorderArcheryLTD]

@@davidkenyon249 every limb length will have its own string tension/vertical deflection data. Limb model and profile

[@Morfabici]

Otra vez muchas gracias¡¡

[@derekhunt9118]

Interesting but quite confusing when you talk of 9 turns adj when most bows only have 6 or less. There are aspects which you have left out, a low brace height can often cause the string to hit the arm and the cheaper the limbs the more this effect, simple less torsional stability in a basic limb. My range is 6 mm up or down brace height. The chrono can simplify the best point within this range but not decide a range from scratch.I agree in most risers there is a point when the bolts are undone a few turns and the bow seems to prefer this setting but nothing empirical.

[@BorderArcheryLTD]

@@derekhunt9118 I didn't leave it out. Low brace heights have substantial loss in string tension meaning the string doesn't stop as quickly. Meaning it's follow through is more, thus slapping your wrist. I also chose a riser with a obscene adjustability as it proves the point of overadjustiment ranges.

[@Tom-d6l]

Check vintage issues of Archery World magazine Nov 75 page 38 for Norbert Muallaneys bow efficiency method. Tom Lund

[@BorderArcheryLTD]

@@Tom-d6l how do I get my hands on that?

[@peterxyz3541]

I need to have enough drinks with this guy so he can dump all his wisdom on me 👍🏼👍🏼👍🏼. I can imagine: the more alcohol, the more mythical the bow becomes. Toward the end of the night, I can imagine he’ll design bows that will take on gods 👽….and the more I want to own one of his bow! Much respect from Ohio! 👍🏼

[@BorderArcheryLTD]

@@peterxyz3541 where are you in the world? And what's your occupation?

[@parandersson8655]

So, if I pick up a random bow, with no available information from the manufacturer, how should I start to work out best brace height?

[@BorderArcheryLTD]

@@parandersson8655 depends on what the manufacturer decided was the main aim of the bow. If stability came second or 3rd... but I'd opt for this

[@dominicking1530]

Is this still relevant when shooting outside of centre on a trad bow when arrow angle changes with the bh?

[@BorderArcheryLTD]

@@dominicking1530 yes. Its always relevant. The nock end movement on low torsionally stable bows is allowed to move lots based on human and spine variances. Centreshot is only a location for catching that lateral outward step of the release(spine) Is that what you meant?

[@tobermory-womble]

Can you explain why increased resistance to vertical nock deflection is a good idea. I'd have thought it would lead to greater transmission of vertical hand torque to arrow flight?

[@BorderArcheryLTD]

@@tobermory-womble if the bow isn't vertically stable or has high resistance to movement, then nock separation can happen at different vertical positions due to varied human input. If you have poor hand pressure on the bow, you simply will never shoot well. But low vertical resistance to movement has much less desire to haul things straight.

[@tobermory-womble]

Thanks Sid ​@@BorderArcheryLTD and thanks for the thought provoking videos. Awesome.

[@ColoursOfDan02]

Good timing. I've been setting up some new limbs with lighter arrows but really struggling to get it to have any forgiveness. I had started in the mid to high brace height and only increased it so far. At the higher end it made me feel like my entire form was garbage. Interestingly it also felt like it had heaps of tension at brace. Time to play with some mid to low settings and see what happens.

[@BorderArcheryLTD]

@@ColoursOfDan02 not just brace, but bolt.positions too

[@ColoursOfDan02]

@@BorderArcheryLTD True, I'll have to try limb bolt positions as well. Thanks.

[@petrokemikal]

If your not carefull a wrong brace height will break a bow.. I bought a new ilf olympic bow 2 years ago and set the brace up roughly midway between the ranges suggested in the manual.. 2 weeks later I started to hear some unerving creaks out of the top limb.. I didnt thnk much of it until one day I said ohh no thats definately getting worse now.. On inspection, the top limb right underneath the string groove was cracked down about 3 inches.. The top fiberglass skin was sompletely delamed, and the creaking was obviously whe youd haul the string back, the crack was opening and spreading progressivly further down the limb.. The cause was the brace height being too short, the string was smacking into the limb skin right underneath the string groove.. I complained to the manufacturer who made me take pictures ect ect I could tell they were thinking I probably dont know how to use a bow.. I told him hey buddy, your recommended brace height is clearly the issue here..I reassembled the bow which showed clear pictures where the string was touching the bow right where the crack started to propagate.. They sent me new top limb after that..

[@BorderArcheryLTD]

@@petrokemikal apparently some limbs are not laminated. But delaminate. Hope you were treated fairly

[@BorderArcheryLTD]

@@petrokemikal riser choice makes a difference in brace height. Low deflex risers. Are always our concerns. Especially ones with more aggressive limb exit angles. There was a German made riser that added 2lbs as well as reduced deflex. Caused all sorts of problems but I was designed by a student. And not a real bowyer

[@petrokemikal]

@@BorderArcheryLTD The bow in question that I had issues with was there own riser and limbs.. Limb 100% delaminated from the string shock.. It was backed with white painted fiberglass on both sides with a maple core.. On a side view you could see the 3 individual layers.. The crack started on the belly side obviously where the string was touching just outside the string groove and ran down about 3 inches before I noticed it.. I could stick a flat head screw driver between the maple and fiberglass layer where it was delamed.. Wouldnt have happened if the brace height was another inch or so.. I know this becase I have the same limb again and now I made damn sure that string was not touching the limb outside the string groove pocket.. Bow is now holding up fine with no issues.. But like you said.. The manufacturer of the bow didnt 100% know how to make the bow with a proper brace height so just lumped in the general 1 to 2 inches... I repaired that limb by injecting laminating resin into the crack and hanging a weight off the tip to close up the gap.. I use it on a homemade bow and its shooting fine.. Freaks me out a bit, but its repaired well... Manufacturer went silent after I sent the pictures of where the string touched the limbs with a tape measure in the pic showing the brace height in there recommended range.. He was all chatty beforehand, obviously thinking I dont know what im doing.. Until he realised I did know what I was doing and then he said Fkkk this im off.. ill send him a limb and he will leave me alone..lol.. They have since change the brace height in the manual Im led to belive..