Maybe it's been discussed here before, but I can't seem to find anything.
How many of you carbon shooters notice your arrows loosing spine strength after shooting them a good while?
They say they are either lost or broke, but I have to disagree. I've shot Gold Tips, Carbon Express and Beman MFX's over the years. All of them start flying poorly after about a year or a little more.
I really can't relate "exactly" how much I shoot, just depends. But, this time of year and sometimes during the Summer it's not uncommon for me to shoot a few hundred arrows or more a week.
Anyhow, after shooting a little the other night and just not hitting well at all, I started trying to pick apart what the hell I was doing wrong. After banging my head, I remembered those other times and switched to some new shafts to check......problem gone. I guess that's the most frustrating part, you don't know quite when it's gonna happen.
I've noticed the same thing as well. I probably should cut them down 1/4" or so.
Was thinking the same, but I keep my arrows as short as I can to help with pass throughs while hunting. They're only 1/4" longer than my draw, so cutting them isn't an option. Next dozen I buy, I'll probably go to the next spine range for a longer arrow, then I can trim them and see how that works.
How about spine testing them? It seems you shold be able to see a difference in spine on a spine tester. If you can't find a spine tester locally you could send the shafts to me and I could test them.
My practice arrows have been shot THOUSANDS of times. I started wondering the same thing right before the IBO Trad Worlds when I was shooting 500+ per week. I have a "Hobbiest" spine tester from 3-Rivers. I spined my practice arrows as well as new arrows and there was NO difference in spine. I have been shooting the same practice arrows for the past two years, and I shoot year round, so when I say they have THOUSANDS of shots, it isn't an exageration. All of my arrows are CX Heritage 250's.
I have some Easton evolutions that are going on 10yrs with alot of shooting out of 75# longbows. No spine change period. Maybe you guys shooting so much your getting sloppy? Don't take that the wrong way! You know what I mean, too much is not always better.
Maybe you got stronger after tuning your arrows and you're coming to a fuller drawer and your draw length has gradually increased over time thus making your arrows react weaker.
Thats it! Your shooting those bows so much your weakening the limbs and they are coming back further.
Guys used to say you could shoot the spine out of aluminums, but I've never heard of it with carbons.
Usually when I suddenly have shooting issues I find my brace height is off.
I don't shoot near that much, so can't speak relative to the shooting frequency.
I do have some arrows that I have been shooting a long time from a wheelie. They have never gotten weaker that I can tell.
What type of carbons are you using? If they lose spine, I will be sure to stay away from them.
I can honestly say that IMO carbons are the most durable, and will take more abuse (bad shots, hitting rocks, trees) than any other type of shaft. They are hard to get up in grain wt., but lb for lb or gr. for gr. they are the most durable.
Farmer
I'll keep some handy to check with a tester. I don't have access to one right now.
I stripped the fletching off a couple to check bareshaft flight and they were weak. Then picked out some new shafts and they shot great.
Some of the other comments are possibilities, but I know that some of the beeman mfx coating gets worn off of my carbons, so I would assume that and other wear could affect spine. I don't have a spine tester, though.
Without measuring the static spines before and
then after, it's a subjective guessing-game. Not saying
there's no merit to the possibility....but this is clearly a
case where some simple spine testing would give you cold hard facts.
What happened is that you form got better and therefore the spine showed weaker. The spine weight doesn't get worn out of them.
In the owner's manual of my Ram Carbon QC spine tester, there's a section on spine degradation. It says spine will degrade with repeated use. Amount depends on type of arrow, type of target, and amount of flexing the arrow goes through. Shows up as a remarkable weak spine point rotationally around the arrow.
QuoteIn the owner's manual of my Ram Carbon QC spine tester, there's a section on spine degradation. It says spine will degrade with repeated use. Amount depends on type of arrow, type of target, and amount of flexing the arrow goes through. Shows up as a remarkable weak spine point rotationally around the arrow.
Starting to think I should pick up a spine tester just to keep track of how my arrows are holding up.
I'll report back if I get my hands on one.
Sounds like you are on the edge to start with. Then any small fluctuation caused you to be out of spine. Gary
P.S. Try a lighter tip
I think freefeet is right !!
I'm inclined to think Freefeet is on the right track. My draw length can vary an inch or more depending on how much I'm shooting. For the life of me I don't know how, but the tape doesn't lie. I think the more my back muscles get engaged the less I drop my head to meet anchor, which doesn't change. I just know to be aware of it and tune it out with point weight over the course of the season.
The statement that all you're shafts are 1/4" longer than you're draw gives me a clue into your thinking.
In my experience it is nearly impossible, without extreme luck or the ability to adjust the bow and tip weight in small ammounts,to cut carbons to an exact length and get them to tune.I always tune a set of arrows to a bow by shaving length in small ammounts untill I reach an acceptable degree of tune.A set of arrows may be any length from 1" to 3" longer than my draw.
It is possible that during tuning a slight variation in form caused your shafts to look tuned.Later your form changed and changed the shafts.
They may or may not shoot weaker over time.Without an accurate spine tester and repeated testing there are just too many variables to say for certin.
I am an engineer and have done quite a bit of work with matrix materials ( carbon is one ). Degredation of spine on a carbon arrows would be very tough if not almost impossible to achieve. Carbon does not degrade over time, and neither does the resins. Both are inert materials. Constant flexion stresses on the arrows can cause degredation over time. Heres the catch. It wouldn't change the arrow spine for very long. Degredation always comes from a hard hit and a crack along the carbon fiber - resin interface. Once a microscopic crack is formed the arrows life is going to be short. An extreme failure will come along shortly, and you will be buying a new arrow to replace the broken one.
I would look to changing form, such as slightly changing draw length due to regular shooting and your arms getting stronger, or perhaps that you are pulling further at the shot for the same reason. A good buddy and mentor of mine in traditional archery says it is the ground connections causing the problem. i.e. I am the reason things are off.
One also has to consider that modern Formula 1 cars are built from carbon fibre and have far more stresses put through them than an arrow and they do not lose strength or rigidity at all.
The Ducati MotoGP bike has carbon fibre sub frames holding it together, and like the F1 car does not lose strength or rigidity the more Casey Stoner hammers it around the track hour after hour - it's the same corner after corner after corner.
Aircraft have been using modern composite materials for a long time, and i'm not aware of any that have fallen out of the sky due to carbon fibre losing rigidity. If it did it would be banned from aircraft use.
Why should a carbon fibre arrow be any different?
QuoteIn my experience it is nearly impossible, without extreme luck or the ability to adjust the bow and tip weight in small ammounts,to cut carbons to an exact length and get them to tune.I always tune a set of arrows to a bow by shaving length in small ammounts untill I reach an acceptable degree of tune.A set of arrows may be any length from 1" to 3" longer than my draw.
I used various brass insert and tip weights. I also added weight (inserts) to the rear of the shafts to get them to spine correctly at that length.
I feel I'm a pretty consistent shooter as far as form, never have much problem reading my bareshaft results to select arrow combinations. I do agree there are plenty variables that can happen.
As far as my draw length increasing, that did happen a few years back when I changed to a different anchor style. But, I sincerely doubt that has any issue here at this time regarding this issue.
I can take this group of 7 arrows (bareshaft now) that are a bit over a year old and they are all shooting weak to some degree.
A new batch (same brand, model and spine) that I made up to the exact specs as my old ones will shoot correctly (bareshaft).
I dropped the point weight down 25 grains and the older shafts are now shooting appropriately.
The spine tester would be the best judgement. But, looking at it from consistent results, common sense says there's a little degredation in the spine.
This thread has definitely got me interested in getting them on a spine tester. I will post the info back up when I get that chance.