Scott Gags

I shoot a 70 pound single cam bow and use a TKO dropaway rest along with a string loop. Is there a downside to having too much spine besisdes the arrow may be heavier?

Trapper_Hunter

THere is a chance they might not group as well.

Sniper151

Scott, you have it right on the money. Arrows heavier that recommended on the arrow charts can be tuned to perfection. The positive: increased kinetic energy. The negative: slower arrow speed. Problems begin when shooters start to drop well below the recommended arrow spine. Tuning problems, string and cable failures and the big one, limb cracking or failure are all inherent traits of under spined arrows.

Bees

seems the bows will accept heavy spine, but they don't like to light of spine. I hunt heavy spine on my hunting arrows and my bow loves it..

BobCo19-65

An arrow with a stiffer spine is not necessarily heavier. Take a 2512 Easton (deflection:.321, weight at 29": 281 grains)and compare it to a 2020 Easton (deflection: .426, weight at 29": 392). There are also heavier carbons out nowwith less spine.

But to answer your question, yes there is a down side to being overspined. What you want is the correct spined (not over or under). What you want is the arrow which shoots through the centershot of a perfectly tuned bow.

Scott Gags

I have heard that too much spine can be a bad thing. I am curious if you or anyone else knows what happens during the firing of the arrow that throws things off. I am not questioning whether you are right or not, just trying to understand why it does it.

elkaddict

If shooting a release (where the significant side to side movement caused by an imperfet finger release is eliminated) what downside is there to being overspined? True, its hard to paper tune accurately, but what practical detriment is there? It seems even with broadheads, there would be litle downside. I have read that even with a release there is still notable up and down flexing and thus perhaps the weaker spined arrow will absorb it and revert to true center sooner, but isn't it harder to get that stiffer arrow oscilating to begin with? Also, is the stiffer arrow going to mean better penetration becaue less energy is expended oscilating? I'm far from an expert in all the nuances of archery. However, noone has provided an explanation that clicks (may be I'm simply to thickheaded to understand). Does the equation change if a drop away rest is used and there is no arrow contact to be worked upon by some up and down oscilation? I've experienced first hand the detriment of weak spined arrows with fixed broadheads--the eratic arrow flight is quite apparent. I've simply not experienced any downside with overspined arrows. Please share your expertise, experience or wild ass speculation!

Rick James

Honestly I feel that the overspine is not an argument that has any definite answer. You will have to see what works on your setup.

I personally shoot a GoldTip Pro 22 series (spine of .300) cut at 28" with a 85 grain tip, which is way overspined according to everyones charts. I have no problems with tears, and it bareshaft tunes well. I have a friend with a 65lb Mathews Outback, he is shooting 27" X-Cutters (.250 spine) with 65 grain points and his bow shoots bullet holes and bare shaft tunes excellent as well. We both shoot these arrows and setups because they are wide diameter arrows and catch a few extra lines for us in competitive 3D, and because they are both very close to the 5 grain per lb IBO minimums.

On the other hand, I hear of people claiming to have bad tears due to overspined arrows all the time on different forums. I really think it is all in how well the bow is tuned, and who knows what else. I have never specifically seen issues myself though with my equipment with overspine.

BobCo19-65

I'm not sure what you are saying. What I am reading is that side to side movement is elliminated when using a release. In that case what would be the difference in using an underspined arrow with a release?

Papertuning will show how the arrow is coming off the bow (I used to use a max of six feet on the compound, I don't papertune my longbow). If the arrow is underspined, or overspined, the hole should note the difference assuming the person shooting the bow has perfect or close to perfect form. It is easy to understand that an arrow coming off the bow straight will not need as much stabilization from the fletches as one that is coming off the bow overspined or underspined. Either way, if the arrow is not coming off the bow straight to begin with, accuracy will be effected. Minor inconsistancy in arrows, fletching, broadheads, form, etc, willmagnify the effects.Paper tuning, if done right, should get you very close to a good tune. However, if you are getting bullet holes with papertuning and you are not close to centershot, then something is wrong.An over spined arrowcan tuned to a bow, however, if the tune is not at or close to centershot, an new arrow size is needed.

Rick James

Good explanation.....

I feel overspine tuning problems are mostly magnified by a improperly tuned bow, or magnified by bad form.