Will restringing change my poundage ?

[SaltyDawg]

BTW:  I never thought it was about a specific string maker and didn't even know you made strings until this last post. [/QB]

OOOOPs    

I'll add one more thing, and then I really will bow out.

The inline string stress at brace on a recurve will a lot of the time be from 18 - 25 percent greater in poundage than the draw weight of the bow. That depends on the bow, and the amount of preload it yields.

On most lonbows it is from 10 - 15 percent increase. Some have higher, and closer to that of a recurve, but few.

[olddogrib]

Trab,
I'm definitely not knowledgeable enough on the matter to explain why, but would highly recommend re-checking the bow's tune after changing strings unless your replacing it with an identical one.  My experience has been that material, # of strands, etc. can make your arrow appear slightly weak or stiff after a change. Most of the time it's required nothing more than tweaking point weight.  That's one reason I prefer to shoot 150-175 gr. heads to give me some range on either side. Obviously you need to reproduce your brace height and keep it there as the new one stretches in also.

[Caughtandhobble]

Yes there is a difference is strings...

I do shoot Rick's strings and I had to increase my arrow spine when I started using his strings. I was shooting FF before I started using Rick's strings and the difference was astonishing.

PS... FYI, I do not know Rick, we've never met but he makes a fine string.

I think that is where some fellows are finding that their Hills are way stiffer than they ordered. The Hill standard is dacron, add a fast flight and the claims of miss marked bows come marching in.  On one that I tillered myself, it drew 55@25, 57.5@26 and 60@27, I put a padded fast flight on it and it jumped up over two pounds.  No big deal, I like how it shoots with it.

[Caughtandhobble]

Originally posted by pavan:
I think that is where some fellows are finding that their Hills are way stiffer than they ordered. The Hill standard is dacron, add a fast flight and the claims of miss marked bows come marching in.

That's not the case here on my part  

Did you get a heavier than expected longbow?

[Caughtandhobble]

Originally posted by pavan:
Did you get a heavier than expected longbow?

Negative, I my bows are rated for FF and are spot on specs. Rick makes the skinny strings and they do require more spine from an arrow than the standard run of the mill FF strings.

I'm a tuning nut to the point that I've been called anal. When I put the 1st string that I got from him my bare shaft poi was about a foot to the right (I'm right handed). I can't verify that the strings have actually changed the poundage itself but I can testify that the strings increases the dynamic spine required.

On my longbows a fast flight will put me one spine size up in aluminum and  5 to 10 pounds spine up with cedar arrows.

[sledge]

does the weight increase of the new string material translate to arrow speed at a higher, lower, or equal rate compared to what 1 might expect from a bow of similar additional weight, but with the original string material?

thanks.

joe

[Jeff Strubberg]

Hrm...

The only way I can see a string change affecting draw weight is if the string stretched enough during the draw to affect how far the limbs pulled during the draw.

If the stretch of the string materials are similar, meaning you are bending the limb the same distance, the weight would have to stay the same.


 

The string/strings actually begin to contract/shrink as the bow is being drawn, and the inline stress starts to decrease.

Say what?

[LBR]

"The string/strings actually begin to contract/shrink as the bow is being drawn, and the inline stress starts to decrease."

How does adding tension reduce tension?

"If I build a string for someone, and the measurement they give me is from their relaxed string measurement. Even if I hit that measurement exactly, my string will be to short for them to use on their bow. Why? Because the string I build won't stretch as much on the bow as most others."

A flemish string is going to settle some, regardless of who makes it or what material it's made from.  I always ask for a measurement under tension for the same reason--strings contract when tension is removed.  Measure it off the bow, it's going to be short.

Again, if you are showing a 4# draw weight difference with everything else identical, just by changing the string, something is missing.

[Trab]

Sorry guys, been out of the house all day and haven't been able to thank everyone for their thoughts and advice. From the general sounds of things, I need to match what I had, and then can expect minimal changes if at all....
Much obliged !!          
Trab

[SaltyDawg]

OK, you drew me back in.    

Let me see if I can explain it.

As the limbs bend you are adding load to them yes, but that same bending is lending leverage to the string, because the stress is no longer being applied to it on a straight line.

Couple that leverage with the 3rd contact point (you fingers), and the string tension actually does decrease as the bow is drawn.

Not counting the apex of the shot - The string tension is at it's highest point when the bow is setting at brace. Any decreas of in line stress, and the string will begin to contract just like any material that has any amount of elasticity.

Trust me - I didn't believe it either, but after after having it explained to me by a cable engineer, and then testing it myself, my eyes were opened. Amazed would be a good way of putting it.

I've repeated the test several times with both recurve & longbow, and the results are always the same, which is - there is always a decrease in string stress as the bow is drawn, and often there is an increase in draw weight between to different strings. The draw weight change will vary, but as stated before, I've seen as much as 4# increase.

Rick

[LBR]

Ok, for the sake of argument say that is the case.  

A 4# difference in draw weight means over an inch of draw length lost.  Dynaflight doesn't have anything close to that kind of elasticity.  Dacron doesn't have that kind of elasticity--not even artificial sinew.

[SaltyDawg]

Chad, what are you doing up so late?

I could ask the same of myself. You know us old guys need our sleep.
Probably like me, and tons of stuff to finish up before the weekend.

Think of it like this.

From how you are stating it - What you are seeing as the draw weight increase is only the bending of the limbs created by the increase of the horizontal draw measurement.

Now look at it this way - a draw weight increase resulting from only the bending of the limbs. Pretty much the same thing as a shorter string.

Shortening of the string increases brace height yes, and it increases the draw weight of the bow, but without changing the actual draw length on the horizontal plane. It is simply bending the limbs more due to the shorter string length.

Now - think about how far the limbs would actually have to travel on the draw, to make a 1/4" difference in the tip to tip measurement of the limbs.

Best I got right now. I'm to tired to put much into it.

Night Brother. Have a great weekend.

Rick

Rick has it right. If you want to really make a bow jump in poundage that has had a flemish dacron on it, put an endless fast flight on the bow, no twists to stretch at all.  Try it on a bow that you don't care if the tips snap off.

[bamboo]

i see it like this--3/16"--really?--4#?!--i call pseudo science!!---the guy asked a simple question which called for a simple answer!!

[SaltyDawg]

bamboo - you need to look at it again.

The 3/16" was when drawn to 28", and there was only a 2# difference.

The 4# difference is when drawn to 29"

Pseudo science? Really now  

[SaltyDawg]

Oh, and P.S.

Yes the guy asked a simple question, and I gave an answer.

Yes - changing the string can make a difference in draw weight of the bow. That don't mean it will. Just means there is the possibility.

[elknutz]

Thanks Rick, I wasn't buying it at first but your explanation certainly makes sense to me.  Your not saying it will make a 4lb difference, only that it could be possible depending on the string and the variables of material and make. THe idea of string tension reducing as the bow is being drawn is a totally new concept to me, but I think I get it.  I'm not much of a scientist, in fact it was only a few years ago I finally believed the earth might not be flat!