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Discussion Starter · #1 ·


you can see riser flex especially at the top of the window, where the pcoket attaches, at the point of closure at the 1 min mark.

you can also see the longrod holding its position.
but you can see the root of the longrod taking a bit of load mid power stroke and especially during closure

from 3min on, you get to see quite a bit of rotational movement in the riser.

at 3:11 you can see during the power stroke the back side of the window twist out. showing bow induced torque.

you can see the top pocket twist as the bow unloads and the shock of closure. makes that top pocket shake a little

little bit of video i found that i thought interesting
 

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Very nice video.

I was very interested in the archer form. Don't mean to get on a tanget, but couldn't wonder if his hand would come back that far if he anchored at the side of his mouth.

Bowmania
 

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There isn't a piece of that bow that isn't vibrating/twisting/oscillating after the shot. Question is this: how much of it is normal? I'm no expert but something has to absorb all the left over energy that isn't absorbed by the arrow. Is this bad? Or do all risers flex/twist/torque to some degree?
 

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Very nice video.

I was very interested in the archer form. Don't mean to get on a tanget, but couldn't wonder if his hand would come back that far if he anchored at the side of his mouth.

Bowmania
With proper back tension it will
 

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My hand comes back further with a chin anchor then my high anchor. But no one said I was doing it correctly and no one might be right :)
 

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Discussion Starter · #6 ·
there was a older beiter video showing a older cast riser and it turned to jelly on closure.
but riser flex and vibration is much much less than it used to be.
 

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There isn't a piece of that bow that isn't vibrating/twisting/oscillating after the shot. Question is this: how much of it is normal? I'm no expert but something has to absorb all the left over energy that isn't absorbed by the arrow. Is this bad? Or do all risers flex/twist/torque to some degree?
Good points UDS. Like yourself, I'm no expert, but it seems reasonable to assume that structures experiencing that degree of force will deform and flex to a certain degree. If there is no deformation of the riser and limbs will that produce hand shock??? ... just my thoughts
 

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Discussion Starter · #8 ·
Good points UDS. Like yourself, I'm no expert, but it seems reasonable to assume that structures experiencing that degree of force will deform and flex to a certain degree. If there is no deformation of the riser and limbs will that produce hand shock??? ... just my thoughts
if the vibrations clash at the wrong point, you will get a thump through the riser.

you dont want 2 vibrations, clashing at the grip
 

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at 3:11 you can see during the power stroke the back side of the window twist out. showing bow induced torque.
I'm a little confused with what you describe as "bow induced torque."

Isn't the torque induced by the lateral movement of the sting coming off the fingers, which in turn torques the limbs, and therefore causes the torque in the riser? It would seem to me that this phenomenon is what makes a limbs resistance to that lateral movement of the string so important. Whatever starts in the limbs resonates through the riser, yes?
 

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Discussion Starter · #10 ·
I'm a little confused with what you describe as "bow induced torque."

Isn't the torque induced by the lateral movement of the sting coming off the fingers, which in turn torques the limbs, and therefore causes the torque in the riser? It would seem to me that this phenomenon is what makes a limbs resistance to that lateral movement of the string so important. Whatever starts in the limbs resonates through the riser, yes?
its different to hand induced torque by way of pushing the grip off centre
 

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I think I understand what you are saying.

So then is hand induced torque what you were referring to when you said bow induced torque?
 

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I remember a video of a bridge oscillating in high winds, at a frequency complimentary to the wind, and the bridge did not collapse as it was structurally sound and built to absorb these oscillations.

So, perhaps a well built riser will absorb or flow with the natural frequencies of the limbs and string resulting in a cleaner and more comfortable shot??
 

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Discussion Starter · #13 ·
I remember a video of a bridge oscillating in high winds, at a frequency complimentary to the wind, and the bridge did not collapse as it was structurally sound and built to absorb these oscillations.

So, perhaps a well built riser will absorb or flow with the natural frequencies of the limbs and string resulting in a cleaner and more comfortable shot??
there was a company that tried to sell that sales pitch.

My question is, what frequency to you get from a 20lbs vs 50lbs bow.
bow with a stabiliser vs one without
Bow with glass limbs vs one with carbon limbs.
one with a top weight vs one with a bottom weight...

all these will change how the harmonics work.

string mass and arrow mass and draw length all change things.
 

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The riser looks to be a PSE X-factor, which are supposed to be pretty stiff. I wonder what an Excell with hunting weight limbs looks like?


-Grant
 

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Grant I am getting a gopro, and have a 21" excel with 54lbs limbs on it... I will shoot it and video it so we can see... I also have a 23" GMX to compare with.
 
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The riser looks to be a PSE X-factor, which are supposed to be pretty stiff. I wonder what an Excell with hunting weight limbs looks like?

-Grant
I have 50# limbs on an Excel. Just dont have a good video camera. That would be interesting because although I like the riser you can definitely feel it flex when you draw. I've shot very well with this riser and 40# limbs, though.

I guess my bigger question is this, and maybe its just personal taste, is there an optimum stiffnes to a riser? Can it be too stiff? Personally, I like the feel of a stiffer riser, and find more benefit from a riser that has heavier mass and good balance.
 

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Discussion Starter · #17 ·
Grant I am getting a gopro, and have a 21" excel with 54lbs limbs on it... I will shoot it and video it so we can see... I also have a 23" GMX to compare with.
caution. the go pro does suffer from rolling shutter effect.

so if the movement is close or faster than the speed the Cmos sensor picks up the image, you can get some strange effects.

Diagonal trucks
Wobbly bow strings.

decent high speed costs LOTS of money.
 

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Discussion Starter · #18 ·
I have 50# limbs on an Excel. Just dont have a good video camera. That would be interesting because although I like the riser you can definitely feel it flex when you draw. I've shot very well with this riser and 40# limbs, though.

I guess my bigger question is this, and maybe its just personal taste, is there an optimum stiffnes to a riser? Can it be too stiff? Personally, I like the feel of a stiffer riser, and find more benefit from a riser that has heavier mass and good balance.
I think stiffer is better.
trying to find optimal is a mission as every bow is different.
 

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If bow torque of any variety is enough to twist an aluminum riser what is it doing to the limbs? There is no way the limbs are laterally stiffer than that riser.
 

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Discussion Starter · #20 ·
If bow torque of any variety is enough to twist an aluminum riser what is it doing to the limbs? There is no way the limbs are laterally stiffer than that riser.
so whats your point?

I dare say, you would be foolish to abandon laterally stiff limbs just because the riser flexes.

Stiffen the riser and allow the stiff limbs to do their trick....

that's kinda what we have been trying to do...
 
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