2016 vs 2018 spine when adding weight

[Strutter]

I am currently shooting a 2016 @ 28" with 155 grains up front.  They fly and bareshaft great.  Total weight is 495 and my bow is [email protected]. If I went to a 2018 the same length the weight would be 540 with the same BH that I have now.  I assume they would be stiff so what I would like to know is how much weight would I have to add up front to get the 2018 to spine like the 2016 does now?  Is there a way to figure this?Hope this makes some sense.  I think I may want a little heavier shaft for elk or is the 9 gr per lb that I now have enough.

Thanks,
Rob

[The Whittler]

Get a couple and try um. You may have to have the arrow a little longer. Alan

[Seeking Trad Deer]

I shoot 2018's at 29 1/2" out of a 60" Fedora 560 that is 60# at my draw with a 125 grain Magnus II and a 75 grain insert (total of 200 up front).  I haven't tried much more as I'm up there at 18% FOC territory if I remember correctly.  Total arrow weight is 600 grains.

[Steelhead]

You can try a heavier point but i think just cutting the 2018 a inch or 2 longer would work very well.They might even work at the same length.especially if the bows center shot and spine tolerant.I have bows that shoot 2018 and 2020s both well.I am shootin 2018s out of my 51 pound at 30 inches longbow and am gonna try some 2016s out of it soon.I suspect they will be okay out of this bow.Only testing will tell for sure.good luck

[Jerry Jeffer]

You might not have to add weight or length at that draw weight. Again depends on bow tolerence.

[DarkeGreen]

I don't think you'll have to change anything. I have two 2018's cut to 29" with 125 gr points on them. When shot from my 55# @28" longbow they are my best flying arrows.

When I plug your numbers in to the program it says you should be using a 2018 if you longbow is of modern design (mine is). If you're shooting a slow bow or selfbow that may be why they fly okay. I tried 2016 from mine and thought they flew good until I went with the 2018's I discovery the flyers and other weird things I noticed from time to time went away. The 2016 where just slightly under spined and when I drew short they flew good, the extra inch I drew as my draw increase caused the 2016 to go crazy from time to time.

Buy one 2018 and give it a try.

[ckruse]

The spine difference between 2016 and 2018 is only about 6 pounds. Should be an easy adjustment with the above advice. CKruse

[Longbowmark]

Strutter,
After years of working in a traditional archery shop I can tell you that spine is not just an issue of comparing the bow weight to the arrow lenght Many factors effect how your arrow shoots.  Adding arrow lenth does drop the stiffness but two more inches of arrow can be a pain when crawling through the bushes.  I would suggest two things.  One, if you can get your alluminum arrows sweged.  This will increase stiffness a little but it makes the allum. arrow easy to work with.  If you have done that, you can ad an insert into the arrow in the form of some of that weed wacking string.  This is flexable and wont effect spine but will give you the extra weight.  You can also spray non expanding foam into the shaft before an insert is placed in or it is tapered.  This will help quiet your arrows as well.  Now, if you go to the 2018 which I dont thing you will need to after the last two ideas,  you can cut your arrow to lenth, swadge (sp) the arrow and us a heavy (190 gr) broad head.  I bet you will be amazed at the flight with the weight forward configuation. Best of luck