PoleVaultPower.com

Each company has a specific span they use to support the pole. This span gives a reading much different if it is a larger span or a shorter span.
One company uses a longer span as they feel it give them a much more accurate number.
Bottom line the flex number is only a relative stiffness number of what a manufacturer has out there!
Some have lost the reason for the de-flexion measure, as it was made to measure the sail of the pole, the area of bending. A longer span takes other parts of the pole into its calculation area that may no bend! Having more spans does provide a more accurate measure for the manufacturer, but gives the athlete and coach much more change moving to the next length to consider!
Many will be surprised when I state this next fact!
The flex number has no correlation with the weight load of the pole.
In fact, I measured a pvc pipe at the same flex of a 120 lbs vaulting pole, but it would never support that weight!
The weight load of the pole or the rating it is awarded is based on the manufactures pattern of the pole, the amount of wraps of pre-preg glass, the size mandrel, and the type of glass are the basic variables! (and there are many others).
While the flex number of each brand may be different the number awarded to a weight rating is very much equal across the board of brands give or take 2.2 lbs.
The flex number is a guide to allow the manufacturer to measure the pole they just made and how it compares to the ones already in the field!
While many coaches and athletes use the flex number to finite their pole selections it has been on purpose a method of confusion by the manufactures to insure you will stay within their flex system!
I have from time to time seen schools buy the same size pole but in a different brand each year, this is a waste and they should always just fill in their blanks spots of their series! Some very good deals can be made trading poles with other schools and buying used poles from major pole rental companies!
IN today's economy coaches and athletes have to build series of pole for camps, schools and Personal collections. A hodgepodge of many different brands seems to be the norm and acceptable!
I propose we have a manufactures flex number on the pole and a universal flex number that does not use so many spans and can be interpreted easily by all!
I also think there should be a conversion table for the various flex brands so a coach can convert those he has in stock to all be on the same Universal System!
(I am working on such a program to covert all flex numbers!)
Bruce Caldwell

1st - you will never get the manufacturer's to agree on one -- who's would you use or would it be a new

ASTM looked into it - lots of issues - decided not in anyones best interest to pursue

There is some correlation of flex numbers to end loads - load cell to measure how much force to keep pole bent to a certain percent (say 70 percent of orginal length)

Could have endless hours of discussion -- what would it result in?

In our stash of poles we have Skypole, Pacer FX, Spirit, Nordic, Essx, Rocket, A steel Gill Vault Master, Carbon Mystic, Nordic Carbon

Seem to have figured out how they all fit.

I am very curious about the flex number on that steel Vault Master? grin

I value your opinions and comments thank you for a reply!
Glad you see the value of a FLEX converter!
Bruce Caldwell

It would be nice to have a standard and yes I would favor it. On the other hand the real difference in brands is not their mid point flex measurement but instead how they are made and how consistent each pole is made throughout the line. I've got a Pacer Mystic 170 and a Spirit 170, both 12 foot poles with the exact same flex measurement. Do they perform the same? Absolutely not. The sale pieces are in different spots on the poles and the bend and recoil are quite different. The one place where I think benefit could come from would be in determining weight ratings for poles. That would be a area where the manufacturers could come together and determine a universal flex number for a specific weight. Case in point would be the two poles I mentioned above. Both have a 13.5 flex measurement and both are 170's. I can tell you that I am positive that wasn't a planned deal, it just happened that way. All in all, pole manufacturers need to have the ability though to "be different" in their designs and offerings to remain competitive and progressive. There's an argument against any further standardization because it limits further breakthroughs in technology and designs. So my official vote is ......YES!........NO WAIT A MINUTE....I MEAN NO......OR....I'VE GOT IT, ABSOLUTELY DEFINITELY.....MAYBE. Later...............Mike

Souleman you have made some good points. I had always thought standardization of the flex chart would block breakthroughs in technology.
Further tests have resulted in the fact this is a measurement of relative stiffness and if the sail is what is measured the movement of the sail will affect the flex number but the measurement method and results will still be measurable.
I make a new Power-x pole and was surprised to see the flex change due to the position of the sail, however knowing this change I have been able to work around it and provide the product which has a broader range of flexes between sizes. Not to get into pumping my new thing but the pole has been successful and has fallen within the range needed to be comparable to other brands easily! If the industry makes a breakthrough a new measurement method may be needed!
Other words when the shoe industry had sizes then added widths and are now finding other measurable variables to provide the best fit!
A vaulting pole with a exact same flex as another brand if flexed on the Universal flex or the same span even will line up. If my info is correct both of the brands you have are on the same span of measure and you are correct they act and fee different. But the load for each is less than 170 lbs.

All my test and data gathering have resulted in all brand being very close to each other weight wise on the measure.
A 170 on one pole is a 170 on another brand this part is accurate. Furthers acceptance by the public is needed.
Bruce Caldwell

souleman wrote: I've got a Pacer Mystic 170 and a Spirit 170, both 12 foot poles with the exact same flex measurement.

That's surprising because Gill and UCS flex 12' poles on different spans. I bet if you flexed them yourself they would have different numbers from each other. If the Mystic was made before 2003, then it would have a different weight rating and flex number under Gill's current system. Also keep in mind that Gill does their 12' Mystics in 5lb increments and UCS does theirs in 10lb increments. And I generally find that Spirit 12' poles, when held at or under the weight label, tend to feel ~10lb stiffer than current Gill 12' poles.

When you get to 13' poles and longer the manufacturers are all fairly similar in how their poles feel in terms of relative stiffness. ... well I don't have much experience with current Nordic or Altius, but I hear they are similar. 12'9 and shorter is a different story, but with any of the current poles they are within 10-15lbs or so. Enough that it can be a problem if you bounce around between brands, but not a big enough problem that someone is likely to injure themselves because a 12'120 is a bit softer or stiffer than expected.

ESSX wrote:I am very curious about the flex number on that steel Vault Master? grin

I value your opinions and comments thank you for a reply!
Glad you see the value of a FLEX converter!
Bruce Caldwell

0.00

A steel vault master with a 50 lbs weight would be about a 2.0 flex number as the weight would pull it down some grin

(rainbowgirl) but with any of the current poles they are within 10-15lbs or so. Enough that it can be a problem if you bounce around between brands, but not a big enough problem that someone is likely to injure themselves because a 12'120 is a bit softer or stiffer than expected.

Between nordic and altius as well as UCS I have seen almost 10 lbs difference nordic being the stiffer one.
they are about 6.6 lbs stiffer than ESSX and Gill poles. It has been a long time (about1985) since I have seen a 15 LBS difference between poles and it was on a Black Nordic carbon bottom pole!

Bruce Caldwell

ESSX wrote:It has been a long time (about1985) since I have seen a 15 LBS difference between poles and it was on a Black Nordic carbon bottom pole!

Bruce Caldwell

When you get into the 11'6 and shorter poles you can get a pretty wide spread sometimes.

ESSX wrote:Between nordic and altius as well as UCS I have seen almost 10 lbs difference nordic being the stiffer one.

I want to be sure I understand what you mean by this. Is it that a pole rated at xyz lb by company Q is stiffer than a pole by company R rated at the same xyz lb? And that stiffness difference is the equivalent of comparing the xyz lb pole of Q with a xyz+10 lb pole of R? Or said another way that xyz lb pole of Q would have the same deflection measurement (if measured the exact same way) as the xyz+10 lb pole of R?

You are making a good point it is confusing.
but the bottom line is the poles are the same stiffness but with different spans they (each company) provides a different number.
And may be awarded a weight rating a little different than their competition
Where one company is using a different spans to support the pole. the weight will provide a new or different reading.
Picture a span then a weight in the middle the longer the span the softer this pole reads or the bigger the flex number.
And visa-versa if a shorter span.

All we are reading here is the area of the pole that bends with a vaulter, the testing device is the same for all companies and they are all measuring the butt stiffness of the pole , not area 8" up and not the area between your hand grip.

It is all relative to what they already have out there!
I prefer we keep it simple rather than complicated.
Bruce Caldwell