spine, why is too stiff bad?

[Palmetto Bug]

I understand that a traditional bow shot with fingers needs some flex in the shaft but on a centershot compound bow shot with a release, what problem will result from a too-stiff arrow? Why does an arrow from a centershot bow with a release need to flex? I figured it was imply a trade off with weight; stiffer means heavier so folks go with as light as possible for speed.

From my own experimenting, going too flexible on spine ruins accuracy but I've seen no perceptible difference going stiffer, as long as I maintain acceptable FOC.

Stripa or other bowmasters, Can you enlighten me?

[dixiedeerslaya]

So you like stiff shafts ehh?

[Palmetto Bug]

Can any heterosexuals answer my question?

[duckduckdog]

Glenn can - oh wait, you siad hetero..... sorry.

I really don't think that too stiff will hurt anything other than adding weight as you already said. I'm not a bowmaster, but that's what my thought process tells me. The less stiff, the more engery you lose through flex in the arrow, so in theory, a stiffer shaft would result in less engery loss so, you should be able to find a stiffness /weight combination that balances resulting in the optimal speed.

[FBT]

arrow flight issues are magnified when your arrow is overspined. If your setup is perfectly tuned, overspine should not be a problem. that was just a guess but it sounds good. someone who knows for certain please clarify.

[Glenn]

arrow flight issues are magnified when your arrow is overspined. If your setup is perfectly tuned, overspine should not be a problem. that was just a guess but it sounds good. someone who knows for certain please clarify.

Pfff, democrat please. FBT knows and he said it.

Too stiff is/can be an issue with center shot bows and I don't care how stiff it is, when that string is turned loose that arrow is flexing. Bank it.

The more stiff the arrow the faster it will recover but it'll flex no doubt.

All a center shot bow gives you is a wider spine range that will "work" for your bow/arrow combination. I.e. you can shoot the same arrow with the same weight but have more range in point weight.

[Stripa Swipa]

I'm reachin here but you called me out.....

There is very little chance that the force applied to the arrow will be directed perfectly down the center of the shaft...even on well tuned center shot bows. So, you need some flex for forgiveness...even if in tiny amounts on modern rocket launchers. If the shaft is too stiff, it would magnify whatever force is at play that isn't in perfect alignment.

How'd I do? Only one shot into the Black Bush.

[duckduckdog]

See - I told ya I didn't know...

[2thDoc]

stiff is bad bc it WONT flex and recover. bows are just not exact enough. without flex you get straight(er) arrow flight, likely in the wrong direction.

[turbo]

Don't think that just because you're shooting a release aid, you're not torquing the string somewhat.

As has been said a couple of times here, the flex is your friend... You need some...

[Dook]

That lil bit of flex we do need is in the composition of the arrah right? I mean they wouldn't sell arrahs that state they can be cut down to 26" - if when cut they were lacking the flex to be accurate (release/flex/straighten in flight/pop target). Correct? I mean as bow hunters and arrah makers we don't make up the composition of the shafts we shoot right.......

use small wurds so I don't get confused....LOL/

[Catdaddy]

That lil bit of flex we do need is in the composition of the arrah right? I mean they wouldn't sell arrahs that state they can be cut down to 26" - if when cut they were lacking the flex to be accurate (release/flex/straighten in flight/pop target). Correct? I mean as bow hunters and arrah makers we don't make up the composition of the shafts we shoot right.......

use small wurds so I don't get confused....LOL/

Dook, when they say the arrow doesn't flex, they are meaning it doesn't for the force/push that a particular bow puts on the arrow. Keep in mind that an arrow that doesn't flex with a 60 lb bow may flex perfect for an 80 lb bow.


So you need to match your arrow with the poundage and draw length you are shooting.

[Palmetto Bug]

Stripa's reply makes sense to me. I'd still like to see a super slow motion video of it to help me visualize it. I still can't totally buy it because like I said in the original post, my experimenting doesn't seem to show any problem with overspined shafts. Perhaps my stiffest arrows are still in the acceptable range of spine for my set up? The moral for me was to err on the side of too stiff instead of too limber.

[2thDoc]

for a compound, yes. but the range of acceptable spines is much smaller in a traditional bow.

[Stripa Swipa]

For Dook and maybe others....just a different angle on spine (stiffness).

When I wuz a younger dude, Gary Loomis shared the simplest explanation I've heard on spine. I was playing with fishing rod designs and he was as knowledgable as they come in that industry.

Think of a diving board. It's stiffness is fixed. If you jump off of it you'll get thrown a certain distance. If you hang a bucket of concrete off of the end, it isn't going to throw you as far. The diving board's stiffness hasn't changed, but it's ability to toss you has. Arrows have a fixed stiffness (spine). When you change point weight, force applied from bow, alignment, length etc etc you are changing it's ability to perform a certain way.

When tuning, you have started with a shaft that's stiffness is fixed. With compounds, you have umpteen factors to worry about, play with, adjust etc that will have some impact on the shafts performance. What is material to you (Palmetto Bug in this case) is totally up to you.

I enjoy tinkering for good arrow flight and better penetration. As I've said before, though, that is probably a small part of recovering game. Quietly putting an arrow through both lungs is 90% of the game....there were no carbon arrows in Agincourt I'm guessing.

[2thDoc]

first one i could find. I am sure there are others that are better.

[2thDoc]

mythbusters: I didnt watch it, but here's the link

[Dook]

Thanks, I got a good visual of it, and maybe I am going to over simplify here with toof, and say if it ain't broke, I ain't fixin it.

I have to ultimately agree with Stripa, hitting him in the right place is the 90% I need to worry about, and I will let carbon xpress worry bout buildin arrahs.

[Stripa Swipa]

Dook,

There is only downside to that approach....
When you stop hitting him where you want to, diagnosing the problem requires others. If you aren't hunting in BFE, that may not be a problem for more than a morning hunt.

[Stripa Swipa]

One other thought for Bug on the practical value of an arrow having some flex....PENETRATION

No arrow is going to hit the target in perfect alignment. As the broadhead starts to penetrate, it's ability to continue penetration on that path is by having the flex of the shaft make up for the arse end that is carrying momentum towards a different point of impact.

Disclaimer.....no Black Bush to help this train of thought so it might be off the mark.