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Thread: Trying to work out recurve limb weight for a child!

  1. #1
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    Trying to work out recurve limb weight for a child!

    I'm getting to the point where I think it is just guess work!

    I'm in the situation where I don't want to buy new limbs and the nearest archery store is that bit too far away to make it worth while going and trying kit out.

    Basically my daughter currently shoots recurve. She has a Hoyt Excel 21" Riser and some 14# limbs. The tiller bolts are currently wound in all the way and it gives 11# at the fingers. I think draw length is only around 20" - will check next time her bow is strung up.

    She is finding 11# OTF far too easy and can hold it on full draw for an age. It has been useful for her to work on her form but I think it is time for her to increase. I would like to try and get some that would be around 15# OTF for now.

    I've actually ordered some that seemed a good buy, with the thought that if they are too heavy I can save them for a year or two, or just sell them on.

    The ones I've bought are 22# limbs. To be honest I'm guessing they will be too high at 8# heavier but I can wind the tiller bolts out the full 6 turns.

    I just have no idea what it will end up on! I have a hoyt horizon as my riser. I know that my limbs give 38# OTF, with the tiller roughly in the middle. The range on mine goes from 36# all the way out to approx 40# all the way in. So I have a 4# range. Will this be similar on my daughters? Or is the range a percentage or the actual draw weight?


    If I start with hers being 14# limbs (measure at 66") - these become 18# limbs at 62", but then if I take 2# off for each inch less than 28". Then I end up with them being 2# limbs! So obviously that doesn't work out!

    With the new ones being 22#, this would become 26# at 62", but then take of 16# again - makes it 10# at a 20" draw.


    Or looking at it the other way if the current ones are 11# and we do get a range of 4#, then they could be 7# wound all the way out.

    If the new ones are literally just 8# more then this would give 15# to 19#.


    Wow - I feel even more confused! I guess the problem is that junior stuff really takes the calculations to the extreme limits which nobody normally worries about. I presume the guesstimate rules become further and further out the further you deviate from the norm.

    This is partly the reason that I thought, what the hell, and ordered the 22# ones. At least then I can make a comparison and given the good price, I can easily sell them on if required.

    It seems to me that with kids growing and changing draw length on a regular basis (which will then quickly put the poundage up), that ideally I could do with a selection of all the different weight limbs to keep changing between to keep the poundage at the right sort of level!

    What do you reckon?! Make your guesses! What do you reckon 22# limbs will be OTF at a 20" draw on a 62" bow, with the tiller bolts wound out 6 turns!?

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    It's an X AIUK subscriber. Rik's Avatar
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    The weight adjustment isn't quite as simple as that. A better rule of thumb than "2lbs per inch" is "5% of the measured draw weight per inch" but even that is only a guesstimate. If I do that with the 14lb limbs, I get 10.8. Close enough.
    The same calculation would make the 22# limbs come to about 16#. But you'd need to add an error bar to that. Probably not as much as +-1#.
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    Quote Originally Posted by Rik View Post
    The weight adjustment isn't quite as simple as that. A better rule of thumb than "2lbs per inch" is "5% of the measured draw weight per inch" but even that is only a guesstimate. If I do that with the 14lb limbs, I get 10.8. Close enough.
    The same calculation would make the 22# limbs come to about 16#. But you'd need to add an error bar to that. Probably not as much as +-1#.
    Thanks for that 16# doesn't sound too bad. Is that taking into account winding the tile bolts out? Or is that with everything left the same?

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    If you're replacing like for like except for the poundage, i.e. same riser, same length limbs, same draw length, then rather than trying to estimate the # per inch, I would have thought that a simple percentage calculation would give a reasonable idea.
    Whatever your daughters draw length is, she's getting approx 79% of the limb rating @28", so assuming that a heavier limb will have a very similar DFC shape, just a steeper one, then 79% of 22# could be around 17.4# at her current draw length with the limb bolts fully in. Hoyt's manual says "Hoyt Recurve bows are adjustable over a range of approximately 10%" so in very rough terms, winding the bolts fully out might then drop that to around 15.8# - which is pretty similar to Rik's estimate just using a slightly different approach.

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    Having re-read Rik's post, maybe my answer doesn't quite match Rik's, because I suspect from the "The same calculation would make" comment, that his 16# estimate is for the bolts fully in, because that's where your 11# figure comes from.

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    Interesting, thanks Andy. The 10% with filler fits in roughly with my findings on my bow.

    The only variable is the make of limbs is different and the construction. The original ones are a bamboo core, the replacement will be a fibre foam type (I think! - replacement are mybo synergy air)

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