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This past season I had a kid who could consistently jump 6-9 inches higher on a 14'6"-21.0 Pacer than a 14'-18.1 Spirit. He gripped both at 13'7". He just seemed to come off the top of the Pacer with more of a vertical velocity component. He jumped with the standards at 26-30 in. with both. The stiffness of the poles are about equal as evidenced by his similar penetration.(in fact the Pacer may be slighly softer) So I rationalized the difference as the 14'6" has a higher sailpiece position. Now I am wondering what the real reason for this is. How does the Sailpiece position really affect the physics of the vault? Or am I dreaming?
Any thoughts?

Did you notice any difference in the appearance of the bend? Was the bend higher in the Pacer than in the Spirit? Which pole bent more?

Oldcoach wrote:This past season I had a kid who could consistently jump 6-9 inches higher on a 14'6"-21.0 Pacer than a 14'-18.1 Spirit. He gripped both at 13'7". He just seemed to come off the top of the Pacer with more of a vertical velocity component. He jumped with the standards at 26-30 in. with both. The stiffness of the poles are about equal as evidenced by his similar penetration.(in fact the Pacer may be slighly softer) So I rationalized the difference as the 14'6" has a higher sailpiece position. Now I am wondering what the real reason for this is. How does the Sailpiece position really affect the physics of the vault? Or am I dreaming?
Any thoughts?

Let’s walk through this for a possible answer!
14-18.1 is a 165
14’6’ 21.0 is a 156
on our charts
18.1 x 110%=19.1

[color=green][b]So a 19.1 would be an equal with the same grip distance from the top of the 14’0â€Â

Further Info,
Both of the poles were manufactured in 1999.
The Spirit has a weight label of 160 lbs and the Pacer- 155 lbs
I cannot comment on the position (high, low) of the bend in each
The Pacer seemed to bend to a greater angle

one possibility may be that the pacer may compliment the timing of his swing better. i'd guess to say that the longer pacer moves a little slower than the spirit, giving him a little more time to rock back. I can't claim this is true since i've never seen him jump, but through my own vaulting i've experienced this before.

Ash,
I think your right that the Pacer was slower (more bend- could get on top of the bend better). So what makes it slower? is it the sailpiece construction or something else.I would venture to guess that every size of pole does not get a unique optimized sailpiece for that mandrel and length to simplify the manufacturing process. So its possible that this combo for the Pacer fit my vaulter better?

It may be exactly as stated - this pole worked well for the jumper.

The flex number think is a little more interesting - if you flex both at the 13'7" hold that would give you a comparison of the initial stiffenss - what happens when they are bent or loaded up - that is when the hoop strength and when and how much it ovals comes in - also how fast it responds -

Since the flex numbers and wgts are when the pole ships from the factory and Spirits have had some history of softening initially with use - the Spirit could in fact be slightly softer or lighter.

Sail piece design does effect the bend - so does the amount of resin and various other factors.

Not a colorful as Bruce - but hope it helps -

What is your take on why a pole would change it's size after leaving the factory?

Could that be that you are measuring it on a differrent machine and the number you get does not match the one on your flex machine????

I would say that if the pole changed flex or got softer that would be sad for the athlete that paid the money and then had a pole get softer.

What tests have you taken to prove this statement?

Do you have examples of poles that are on the spirit flex machines that are now lighter when measured on their machine again?

I am curious LOL love the colors on here

ESSX wrote:What is your take on why a pole would change it's size after leaving the factory?

Could that be that you are measuring it on a differrent machine and the number you get does not match the one on your flex machine????

I would say that if the pole changed flex or got softer that would be sad for the athlete that paid the money and then had a pole get softer.

What tests have you taken to prove this statement?

Do you have examples of poles that are on the spirit flex machines that are now lighter when measured on their machine again?

I am curious LOL love the colors on here

Jan Johnson did some testing on ALL brand poles a few years ago, flexing them brand new, taking a certain number of jumps, flexing them again, jumping more, flexing again, jumping more, flexing again. He found that Spirits did indeed gain a certain amount of flex(ie: the number increased) the more jumps they had on them. Other brands had minimal changes if any in flex.

Gee Bruce - it sounds like a test question - does the softening happen - yes it does - we have even played with prototypes and by changing certain variables we can build a pole that will continue to soften through quite a few jumps - and by at least 2 cm - we don't recommend building them that way and do not build our production poles that way. I am sure you are well aware of some of these parameters.

The only way I know of a pole becoming softer is something being taken away from it. Like glass or resin?

An old method of coating the mandrel with a resin before tacking used to cause a breaking of resin inside the pole. This would cause a powder to develop on the poles in the pole tip area after about 10-15 jumps.

Thermoflex was the brand name they are not producing poles, as their poles would talk to you when you bend them with a crackle.

We had a similar problem with white training poles and Wonder poles made by Shakespeare the filament winding had resin breaking loose on the inside and the poles after flexing did lose a flex or two. But in all cases we caused this to happen before allowing the pole out, so it had the correct flex on it.

I would think a company would do that first before allowing it to soften in the field? I have seen poles various brands that read different flexes on our flex system, and we felt it was just the differences in the machine.

The system to flex a pole is not perfect. As when we moved the flex machine from Salt Lake City UTAH then to Mexico then to Sun Valley, Ca and now to Fort Worth, TX, the flex reads different by a few clicks in each of these locations.

I heard there was also a difference in flexes when the Skypole flex machine was moved from Ca. to Texas then to ILL and then to Jan’s House in Ca. (Round trip LOL)
The method may be similar but when set up many factors play a part in the reading. Now the differences we have seen at each location and the ones on other brand poles is not enough to be concerned over, maybe the difference of a soft flex compared to maybe a stiff flex. We have a test pole that we use to calibrate and it has not changed flex now for over 6 years.
(Of course we bend it in the machine and no one has vaulted on it!)