After reading some topics about the misleading spinevalues of carbon arrows and some people don't know how to deal with it, I think it's about time to open a topic about this.
A nice subject for my 1000-th post! :saywhat:
Lots of people seem to think that a shaft saying 15-35 is meant for bows within the range of 15 to 35 lbs. This is not true!
The 15-35 comes out of the compound world and has nothing to do with our traditional bows!
Lets take a look at the most common values: 15-35, 35-55, 55-75, and 75-95. More important here is the deflection. This means how much the shaft flexes with a weight of exactly 2 lbs on it, supported on both ends at 26".
If you want to converse these values to more traditional spinevalues, you will have to do some maths. First we look for the deflection value (which is mostly printed on the shaft and is in 1/1000 of an inch) For example 0.600 means that the shaft flexes 0.6 inch when putting a weight on it from 2 lbs supported at both ends at a lenght of 26 inches. This is the same method as with wood, only with wood it is measured at 28 inches. Then we devide the deflection value by 26 and multiply it with 1,2115 which is the factor for carbon.
This should give you the following table:
15-35 or 0.600" becomes: 26/0,6 x 1,2115 = 52,5 lbs
35-55 or 0.500" becomes: 26/0,5 x 1,2115 = 63 lbs
55-75 or 0.400" becomes: 26/0,4 x 1,2115 = 78 lbs
75-95 or 0.300" becomes: 26/0,3 x 1,2115 = 105 lbs
On these calculated lbs values all normal archery laws are applicable: shortening the shaft means a stiffer spine, higher point-weight means a weaker spine.
So for my 45 lbs bow I use a 1535 shaft. On a full lenght of 30,5" and with a 85 grains fieldpoint and standard insert it flies great. Bareshafting tells the same. My woodies tell the same: I use on the same bow 53 +/- 1 lbs Sitka shafts.. That's pretty close to the 52,5 lbs from a 15-35 carbon shaft!
YMMV, so if you have other ideas, theories or whatever, don't hold back. Afterall we are here to learn and share! I am sure there are some people here who do know a whole lot more about arrows than I do :D
It's been my experience with carbons that changing the length of the shaft and adjusting the point weight do not have the exact same effect and should not necessarily be considered an interchangeable fix. I believe that for a given problem changing one of them will work better than changing the other.
I do use a weaker spined carbon shaft than recommended anywhere, but they are the right shaft for my bow, regardless of what the calculators and charts say.
I am just getting into carbon arrows so don't know much. So far my very limited experience would agree with the spine table you have listed. Ordered what I thought were 3555 but put the wrong item number down and received 1535s they shoot great from my 46# recurve. The only thing I did was put some nylon cord in the shaft to get the weight up a little.
When shooting no heavy front weight, total arrow weight can become an issue. You can put something like cord in the shaft, paint the last part of the shaft, glue little leadballs in the nock which asks for a hevaier point, etc. I always take care that I shoot around the 9GPP at least with 10 GPP as max.
I spined some carbon shafts a while back, and your values are about what I came up with. I think that's what started the heavy point craze. You NEEDED 300 grain points to get those stiff shafts flying right.
You might have nailed it :)
Yup all good info there. I use 500 and 600 spine (lon the longer end)on most of my bows from 45-55. Fly awesome. And with 200 gr up front. To combat the weight issue. I've been using the grizzly sticks. They are considerably heavier.
Dutchman: Your numbers are pretty close, accurate for the measurements you're taking, but the premise is a little off.
In the U.S., the 2# weight is used on shafts suspended between posts 26 inches apart, not 28 inches. A similar set up has recently come into use for carbon shafts. In this case a 1.94# weight is used on shafts suspended between posts 28 inches apart. The two measurement devices yield similar, though not identical results.
I have found that carbons can sometimes vary quite a bit in spine. I have 10 Gold Tip 55/75 XTs, for example that spine about 85# (2# wt with 26-inch centers). However, one of those shafts spine over 100#. Maybe mislabled. Don't know, but it's marked the same 55/75 as all the rest.
All the scientific input is great, but the reality is that spine is somewhat relative...
Factors I've found over the past 15 yrs that affect spine with carbons are:
* Draw weight
* arrow length
* Point weight
* Tail weight
* Fletching size and shape
* Riser center cut amount
After factoring in all those things, recently I learned more interesting data from a chap who had built carbon and aluminum arrows for the demanding tournament circuit shooters, both compound and trad.
Enter a new conundrum! :)
His information was that due to the demands of his clientele, he weighed, spined and batched all the arrows he bought. He found that almost all carbon arrow makers have considerable spine variance in any given dozen... and some are worse than others!
Shafts I used were some of the worst...so I ended up bare shaft tuning each and EVERY shaft and found that I had to cut arrows different lengths...some, to get to fly right, were as much as a 1/4" different and some only 1/16th.
Lots of variables in carbon as with natural materials. Learning to eliminate those variables goes a long way toward helping anyone be more consistent in their shooting.
Equipment and form. Variance in either is a real challenge!
Orion, I think the dutchman meant that the shafts were suspended at 26", and the values applied to a 28" arrow. That has been my understanding, anyway.
That explains some recent issues I have been having with the 5575 blems I just ordered for my 58# @28" R/D....Darn it!
My experience with carbons has been limited because I found a combo I like and have stuck with it so far. That said, before even thinking about tuning arrows you have to have consistent form. If you plan to bareshaft tune to your bow you will find that the release is critically important. Assuming you have good (a.k.a. consistent) form the rest is a lot of personal preference...some prefer to pick a point weight and trim the shaft, others build out their riser to weaken the arrow's spine, I like to leave them full length(32" draw does that) and pile on the point weight till it flies straight.
QuoteOriginally posted by Doc Nock:
All the scientific input is great, but the reality is that spine is somewhat relative...
Factors I've found over the past 15 yrs that affect spine with carbons are:
* Draw weight
* arrow length
* Point weight
* Tail weight
* Fletching size and shape
* Riser center cut amount
After factoring in all those things, recently I learned more interesting data from a chap who had built carbon and aluminum arrows for the demanding tournament circuit shooters, both compound and trad.
Enter a new conundrum! :)
His information was that due to the demands of his clientele, he weighed, spined and batched all the arrows he bought. He found that almost all carbon arrow makers have considerable spine variance in any given dozen... and some are worse than others!
Shafts I used were some of the worst...so I ended up bare shaft tuning each and EVERY shaft and found that I had to cut arrows different lengths...some, to get to fly right, were as much as a 1/4" different and some only 1/16th.
Lots of variables in carbon as with natural materials. Learning to eliminate those variables goes a long way toward helping anyone be more consistent in their shooting.
Equipment and form. Variance in either is a real challenge!
You are absolutely right Doc Noc. That's why I sad: On these calculated lbs values all normal archery laws are applicable :) .
I also putted my part of carbon shafts on the spine tester and found out that the the spine value of carbon is not very consistent to say the least. I found deviations as big as 7 lbs on 15-35 shafts. The weight however is very consistent...
I started this thread only to give an understanding how the carbon spine values really are and give a starting point for those struggling with it..
Thank you for clearing out that there is more in this game then static spine-value only, I couldn't agree more with you! :) Dynamic spine value is another thing.
My post was more meant for people saying: "Ok I have a 60 lbs bow, so I have to start with a 55-75 shaft....
Doc,
I found the same thing as far as variation with some. My son also bought some high dollar carbons for his wheelie bow and out of a half dozen, only three flew well, one so-so, and two wouldn't work with his broadheads at all. Oddly enough, the shafts I have found to be most consistent were also the cheapest: Beman ICS Bowhunter. They are not perfect, but they are the closest I have tried. I didn't spine them, as I have no tester, but paper tuning and broadhead tuning gave me very consistent results with them. GT 35-55s are supposed to be .500 spine, but I have to leave them at least an inch longer than the Bemans with the same weight up front. Out of two dozen Bemans, I have had only one that refused to cooperate.
I was thinking about some Beman Bone collectors or some Easton AXIS, has anyone compared these for spine consistancy?
Great post. I agree that centershot is a huge variable. I have a number of recurves from the same bowyer, and the lightest in the group (54#) shoots .400 Beman MFX Classics, just like the 60#. But the 56# and 57# need a .500. Centershot is a major determining factor.
Flying D,
IT was a worthwhile motivation...and I was just building on that... not trying to counter.
I would bare shaft 3 and fletch 3 and then trim to get them all to fly the same...but I'd see "tailing" when I'd get back to 20-25 yards and ignored it...cause they hit the same... uh-huh-uh!
So while you had their attention, I just was hoping to encourage folks to NOT figure because they're high tech carbon that when they get one or 3 to fly well, to cut them all the same...cause there are big variances in a given dozen.
I was AMAZEDin how much effect in flight an 1/8" in length made in how they tailed either left or right!
there is research about indigenous tribes in S. America that tune EVERY arrow to THEIR bow! They may have natural fiber shafting with steel points and each one in their quiver might be a different length... so nothing new here.
And yeah, form is critical...which is why my tuning source recommends shooting 2 shafts at a time and shooting them both at least 4-5 times with total focus on form... to see if you get consistent results before cutting.
Now worries Dave,I didn't see it as a counter...I seldom do. As I said we are here to learn form each other and to share.
I have no problems in cutting woodies to the same langht, but they are spined properly, that is within + or - 1 lsb.
Suppose you would have carbons spined very precise, would tou still have to cut them at different lenght you think? And Yes, carbon is very vulnerable for lenght!
Here is what I learned about carbon shafting recently. I shoot Gold Tip 55/75 XT Hunter shafts. I had my bow shooting perfectly when I set it up a couple years ago. Last year a guy was shooting thru the paper and I shot a couple thru it just cause I was there. At this point my arrows were showing to be stiff. I had no clue why and just thought it was something I was doing different than before.
Fast forward a couple months and I ran across a great deal on a good spine tester. This is one of the ones for carbon arrows and uses the 1.94# weight and gives you a deflection reading in inches. So now I started to run arrows thru the spine tester and I was amazed at what I found. All of my arrows were factory marked as if they were .400 spine. I tested 3 dozen shafts and found NONE OF THEM to be .400 spine. They were all stiffer than .400 ranging from .342 to .371, with most of them being in the .360 to .380 range.
So here is what I now believe: when I initially set my bow up I had shafts that were a bit lighter spined and they tuned perfectly. When I shot thru the paper at the shop I was using other shafts than I had used at first and they were probably stiffer and that is why they showed stiff in the paper.
I now run all my shafts thru the spine tester and group them in .010" sets to use as needed. And Doc Nock was right. Each group needs to cut just a tad bit different to tune perfectly.
Bisch
Carbon's tricky. :D
Last week I traded for some GT XT Hunter 5575's to play with. I removed all inserts, fletching and wraps. I then put them on my spine tester and rotated them about an 1/8" and respined all the way around. After doing a few to see what the range was, I then marked all of them where they spined .380 and then finished them out with the cock feather opposite this mark so that I had the .380 side against the riser. Even though all shafts are cut the same at 30", I have 2-3 out of 11 that just won't group with the rest and probably need to follow Doc's advice and tune them all individually. Problem is.....I'd rather shoot wood. :archer2:
Interesting. Just spined a half-dozen new Easton Axis N-fused .400s. On my spine tester (2#@26 inches) they all spine 80 pounds or a little better -- 3 at 80#, 2@82# and one about 84#. My spine tester doesn't provide actual deflection. The measurement is converted to poundage on the scale. .400 is supposed to be 65#; 80# is about .325 deflection (2#@26 inches).
Maybe my spine tester is off. However, I've checked it against vendor supplied shafts many, many times over the years. Anybody else measure actual deflection on Axis .400s?
Oops. Just checked a chart that shows the deflection using 1.94#@28 inches, which what Easton uses. Using that system, a deflection of .39 is 80#. Close enough.
Obviously, we get very close to the same poundage result, but the deflection related to that poundage varies depending on which measuring system one uses. Looks like to compare apples to apples, we'll always need to state which spine measuring parameters we're using.
If I had a spine tester, I'd use it.
Personally, I wouldn't get too hung up on the 26" vs. 28" center test... or the ACTUAL spine...
Like speed, it's only a measure... I'd be looking for CONSISTENCY... I wouldn't care so much what the actual #-age was, but if there were variance among the dozen!
What I was told is that GT and Victory can be off 6-7# over any given dozen! That is going to take a lot of individual tuning to get them to all group together!!
I got in a verbal tussle with some good folks who touted wood... over carbon due to consistency.
My BAD! Course, I always figured the way they were made and sold, they'd have better control than wood...
One thing I will still say...carbon seems to either be straight or broken... Once you have them individually tuned to your set up...they also seem to last and don't change!
I'll fuss with my gear once to get it right, but I don't care for continued fussing over brace, or arrow straightness... I just want to shoot after all the blood -letting testing is done! :rolleyes: :saywhat:
I have never spine tested and have never tuned my arrows :eek:
but have shot through paper, maybe I'm lucky but it's always been a bullet hole. When I switched from GT3555 to GT1535 My friends thought I was crazy, until they saw me shoot, then many of them switched to GT1535's because we all shoot about the same weight bows.
I just received a new batch of GT1535's in right wing ( I always shoot left wing) and have been shooting GT3555's out of a recurve I recently purchased, now even though they shoot great, I think the 1535's will shoot just as good but a little faster.
By the way, GREAT POST !
Most informative post I've read in a long time. I'm already squirreling away money for a spine tester. IMO this takes out the biggest variable in consistent shooting.
I fletch and wrap all my arrows in different color schemes so that no two are alike - so I can tell which ones are misbehaving. Plus it's camo that way.
Old orangey (orange wrap, two orange and a barred feather) has killed a hog and a rattlesnake this year, so it's my first string. Had to refletch it the other day.
That's science!
I've been running into some of these issues as well. A few good arrows and then the few that refuse to go to the same spot! :banghead:
I discovered that long time ago ,that carbon is not really consistent in spine,like AL.So if you want to have a good matching set you have to spine test every single shaft and make groups that can be set a little differently,like lenght and point weight.
all arrows have both static and dynamic spine values.
the bugaboo is with carbon arrow shafting, and this variation of static and dynamic spine values is far less with wood and aluminum arrow shafts.
almost all carbon arrows are listed with static spine values that are far too heavy in dynamic spine for a trad bow. this is the failure of the carbon arrow industry to take into account how a trad bow engine operates.
what matters most is NOT the static value, it's the DYNAMIC value that decides what best matches a particular length for a particular bow for a particular archer with a particular string. each of these criteria all all encompassing, meaning that in the case of the bow, it's the type of bow, it's stored weight at a particular draw length, and how far the shaft lies from centershot on the arrow rest.
Great post! And what I have learned over the past months with carbons is how centershot places such a great role when considering spine type. Also, how little of shaft length removal can affect arrow flight...it only takes a small amount to make a change.
Good thread.
Alot has to do with how our trad bow shelves are cut. My cut past center shelves shoot a stiffer spine very well as they don't have to flex around the riser during the shot.
A couple of things I have learned shooting carbons over the years is:
1. Start out with them full length and work your way down.(when trying something new).
2. When adding weight behind the insert it doesn't have as much effect as adding it to tip weight.
3. Adding weight tubes don't work well for me.
4. The same spine in small diameter arrows will shoot different than regular size carbon arrows like gold tip. (they seem more forgiving).
5. A 1/4" in arrow length can make a big difference in how it shoots.
I have shot carbons for years I prefer them to other shafting especially for hunting. If I couldn't shoot them anymore I would shoot wood shafts.
Just what I have learned.
LCH
Lee,
For years I've tried to preach the same thing about riser cut as a huge influence on spine.
Years ago, I was testing some new mfg arrows for a friend and made up a 3fletch/3 bare shaft test kit.
Took them to a shoot. All of us who shot around 48-50# bows had risers cut 3/16 past center . They shot weak for us. All had the same draw length, btw.
Another buddy walks up with an IBO legal long bow...cut 1/8 SHY of center. Same draw length.
His bow, BTW, was 65# compared to our 48-50# bows!
They shot STIFF for him and 2 others with risers cut shy of center!
And yet, his bow and the others that shot stiff were all in mid 60# range! At least 15# more draw weight than those of us with weak results but hard center cut risers!
Go figure! Simple stick bows have a host of very subtle nuances that make huge impacts on tuning...
Back in the 60's and 70's I always bareshafted my target tackle (freestyle fingers, recurves, X7's, heavy points and spin wings), and I still believe this is still the correct way to go for a target bow.
I carried the bareshaft process forward with my barebow hunting tackle and found too many occasions when well tuned bareshafts reacted quite differently when fletched. I found it best for me to just tune the fletched arrow to the bow and my shooting style. Target archery and bowhunting have little in common - that's just my observation.
I have no hunting arrow flight issues (using two different types of carbons, Beman's and AD's), they fly straight and true and fast with field points, judos or broadheads. The GPP and fletch cut and FOC and point types don't matter as much as gets touted. I can make most any fletched arrow work well out of my D or r/d longbows with a bit of tweaking here and there at best.
As I was careful to say, "... for me" - I'd never knock what works for others.
There are a *LOT* of factors that will determine what arrow type and spine will work best with what bow and what archer - the archer plays a key role, as your form, physique and aiming method can radically alter the arrow spex.
IMO, some of my opinions on matching arrows to bows and archers ...
(soapbox on)
the closer the arrow plate is to the center of the riser, the far less that spine matters, if at all.
carbon arrows have a FAR greater range of dynamic spine than static spine, which is the reason all carbon manufacturers list a very broad range of static spine for one shaft type and spine. dynamic spine is most important.
if you're a bowhunter, spine will matter less that for a target archer, because target archers need to remove as many variables as possible and always shoot with the same upright stance and vertical bow. we don't. not ever.
carbons LOVE to be pushed hard. this means that you want to start off with a weak spined carbon shaft. at my draw length and arrow length, and with the 250-350 grains up front that i use, the beman charts tell me i should be shooting a 340, instead a 500 fits the bill for me best. that's two spine ranges lower than recommended. partly due to listing static spine, which for carbons is plain dumb.
figure to shoot around 10gpp. this means an efficient transfer of energy from the limbs, through the string, to the arrow, and the arrow will have enuf mass weight to absorb it all. not so good things happen when going much under 9gpp. in fact bumping up higher will yield more benefits, such as less noise on release and more release and inflight bow/arrow "stability".
how you aim plays a critical part of how the arrow will fly, regardless of the arrow's spine. yes. read that again. if you learn to aim the arrow (as all old time longbow archers did), and not the bow, spine is nearly meaningless. this is one reason why howard hill could pick an arrow from the quivers of 10 different archers and put all of them in the bull at 30 yards. aiming the arrow was greatly discussed by jim ploen (21st century bows, and a champion target archer and accomplished hunter) in articles he wrote for instinctive archer.
(soapbox off)
Has anyone with a spine tester ever done any testing On brands such as
Goldtip Trads
Carbon Express Herritage
beman ics hunter
easton axis
Traditional Only
To see which brand is the most consistent from lot to lot or just in a dozen arrows.
Rob's got it pretty much nailed and saved me a bunch of typing. :thumbsup:
However, I still remember testing 35-55's for my 38lbs longbow, a long time ago. No matter what I tried, they would not fly as they should. In the end I took some 1535's and ended up with a 145 grains front load to make them fly right.
So I think spine value can be important, if you are way off, that arrow just won't fly as it should.
I think if you will go above or under 10 lbs, you will notice it. At least, that's my experience. But I think distance plays a role too. When I shoot at 15 yards, I can shoot every arrow, every spine, every weight, every FOC. When I shoot at 50 yards, the story becomes quite different...
I have a spine tester and have spined FMJs and the MFs classic Beman 400s. The Dozen sets I have spined have all spined the same. on my spine tester set at 28in, not 26 with a 2 lb weight spined 425 or 2216 alumimun..I have found these to be as close as aluminum shafts.