Dumb question

[bear bowman]

I see posts quite often regarding tuning arrows. I'm relatively new to all of this so here is my question or questions.
I see that so and so shoots a 50# bow and shoots a certain spine weight carbon. He only draws X" so his draw weight is more like 46#. Why is it that one persons setup at a certain weight could vary so much from mine or anyone else's? Are the bow efficiencies that varied?
I ask because I shoot roughly 47# with a 35/55 and 175 up front and the next guy will shoot 55/75 out of a similar set up with about the same weight up front and get good results also?
I'm a little confused to say the least. Again, I'm pretty new to this stuff.

[DDawg]

If I'm getting what your asking,
The stated draw weight of a given bow is usually based on a baseline draw length of 28".  Hence, 50# at 28".
So if your draw length is less than or greater than 28" you will be pulling less/more weight than 50#'s, and that must be compensated for in your arrows.
I kinda new too so sorry if I miss read your question.

[Orion]

To start with, most bows will shoot a range of arrow spines quite well. Though there probably is one optimal spine, arrow weight, point weight, bow weight, etc., combination, most folks don't have form good enough to find it.  That's not really a problem.  They can still find a combination that shoots well for them.

The amount of centershot on the arrow shelf has a substantial effect  on tuning -- the more centershot, the more spine is required.  

Arrow length also affects the dynamic spine of the arrow, the shorter the arrow, the stiffer it becomes dynamically, the longer, the softer.

Of course, the amount of weight up front also affects the dynamic spine, the more weight, the greater the foc and the more it weakens the dynamic spine.

All this to say that the bow/arrow combination will act differently depending on the construction of both the arrow and the bow.

And, on top of that, there is individual shooting style/form. It probably has as much to do with what arrows fly right out of a bow than any other factor.

Just a lot of variables involved and no one size fits all.

[reddogge]

Orion basically covered it. Depending on the length of your arrow (some people like me like to shoot long arrows even though my draw length is not that long) and point weight a wide range of arrows could be shot out of a particular bow. I shoot .500 and 2213s out of 45# bows but I have a 47# bow that loves .400s.

The only way to find out what will shoot out of your bow is do a tuning session. Use some basic guidelines to select a starting shaft and tune for a certain broadhead in mind or a certain shaft length in mind.

[olddogrib]

Orion nailed it...centershot.  but now you know that the "dweeb" who claims his 40# bow shoots so hard it has to have 75/95 spine is totally clueless...and likely has arrows that are tuned even worse, lol!

[bear bowman]

Thanks guys. The more I read, the more confused I was getting. I was starting to question my setup based on others. I need to stay with what works. Thanks again

[Cavscout9753]

It can get a little crazy, I agree. Sometime for fun go over to 3 Rivers Archery's web page. They have a spine calculator thats fun to play with. You just input the data and it'll tell you how close your setup is to being "tunable", its not perfect (what is?) but it always gets me pretty close. Like Orion said, individual form plays a factor, but if you want to mix it up like say, trying for heavier or lighter arrow weight, or some broadheads you want to try, it will get you close to what spine you should be looking at. It doesn't negate tunning of course, but its fun to see what you can cook up without piles of shaft test kits and a mound of tips and 1/4" pieces of carbon arrows laying all over.

[Yewbender]

Bear Bowman...not a dumb ? The great thing about Tradgang is the guys on this site are Willing to help others out and they are a wealth of knowledge. Orion hit it on the head and some other good advise too from others.

[Russ Clagett]

That's a great question.

"How many barks does a dog have?"

Now THAT'S a dumb question.

[Butch Speer]

Bear,
What Orion said.

If your broadhead arrows fly good and hit where you're looking, then you have the right arrows. Really doesn't matter what the charts say, although they do help, or anyone else shoots.

[Butch Speer]

Sorry for the double.

[**DONOTDELETE**]

Orion listed just about everything except the variance in different bows efficiency....

There is a much wider range in bow efficiency out there than most archers realize..... The farther the bow is cut to, or cut past center, the wider the spine range will be to get arrows tuned....

 The center shot location, and arrow length has a much more dramatic effect on dynamic spine than tip weight alone.... the longer the arrow is, the more the tip weight comes into play in effecting dynamic spine.