ABOUT FLEX NUMBERS!

Indoor industrial workspace with pipes and equipment.

The Truth About Flex Numbers

The flex number is awarded to a vaulting pole to help Pole Makers produce consistently the same pole as is in the field. Keeping consistency over the years is important to ensure the pole is cured and produced in the oven with as many consistent variables as can be maintained. The same pattern, the same resin percentage, stable heat and humidity, and other natural variables that affect the outcome of the pole. Any variant of the pattern will change the pole's stiffness.

Diagram of a triangle with labeled segments A, B, C, D, and E.

Flex Number Origin

The origin of flex system for vaulting poles was introduced to the industry by Herb Jenks, carried over from the defection measure of an arrow shaft's spine. He designed a vaulting pole with multi-variable sail wrap widths that changed the stiffness of the pole. His original setup was strictly to measure the sail wrap. This measured 6 inches up from the butt of the pole and right at the tip of the top of the sail piece. (See Photo image to the right) and required a set span that matched the sail's length for each length. A 144" (12' ) span for 14' poles was what he started with. When hanging a 50 lb weight from the middle of the span on the vaulting pole, the pole deflected in inches (") today converted to centimeters (cm). All PoleMakers use a metric measure; Altius still uses Inches. Those can be converted Inches to metric example, 7.4" X 2.54=18.8 cm.

Cartoon boy on weighing scale with the word 'Weight'.

Flex Number Myth's

When the Pole is positioned on the span 6" from the butt end and the full span length, the less friction that ...can achieve yields with the most accurate measure; believe me, this is a good system. It is used by many trying to perfect it to an exact measure that an engineer in the business would seek.

(However, Flex Numbers are Overrated!)

Please do not lose any sleep over trying to be a perfect flex, as you will never get an exact number even on your own system. Many variables are here in this system humidity, weight deviation spans used, and location from the equarter, one may have to check it 3 times we do it 5 times. The system has flaws, and knowing this, I have found that if you strive to make a pole with a mid-flex number, you can eliminate pole crossover weight ratings. This will help you to move from one pole to another.

Overcoming Flex numbers

A measure of .1 (") or 2.5 (cm) is about one lb. of stiffness, and why do people get so wrapped up in the most accurate flex number that can be overcome by just raising or lowering the hand grip, 1 or 2 inches?

MORE FLEX NUMBER INFORMATION

Weight Ratings

Weight ratings are always very similar, from Brand to brand one Brand, Sometimes 3 lbs. to 5 lbs. softer or stiffer. This difference is based on two things:

How easy the pole was made to have a durable bend, pre-bent, or the ability to roll-over.
The weight load cell reading.

In the past, Pole Makers used to measure the weight load of 140 lbs., but call it a 130 test to add what was called back in the day a "fudge factor" (a calculation to account for error or unanticipated circumstances.) They also made poles with the sailwrap longer and higher than today. This made the pole hard for novice vaulters to bend and those that may have bought a pole longer than their ability. (defined as a pole 18" above the vaulter's best ability.) We have a true-weight rating with no "fudge factor". Bending a pole is necessary only after you have learned how to swing on the pole. The process has to be easy, or you will be thrown back down the runway. Let a qualified FiberSport reseller help you to be fitted to a pole. You will jump higher and save money on poles.

Modern Evolution in the Pole Making today!

Since 1980. improved designs in the sail wrap design to facilitate the pole to roll-over better, allowing athletes to capture the ride (So to speak). Improved resin systems to coat and impregnate the fabric improved in 1989. IN 2012, Improved consistency fabric weaving of fabric. I introduced a better compaction system to eliminate air voids in the fabric and seal the pole. This has proven to be the answer to "the Durable Vaulting pole."

Pole Makers cannot use a Universal Flex Chart.

We have studied this and have introduced the idea at ASTM meetings to no avail. Far too many variables and variances, plus engineering ideas, seem to overthink this, in my opinion.

Reasons why not!

1. The span to support the pole is different for each manufacturer.

Some measure bigger spans and more of the pole. Some think this is better, and they have forgotten it is a SAIL WRAP measurement.

2. Some use a weight in pounds and others in kilograms. (22K does not equal 50 lb.)

3. Some measure 6" from the butt of the pole, and others 12".

4. Many have had their FLEX NUMBER out in the marketplace for years, and to change or adjust at this point would be devastating to match future poles to what you are using.

I was once told that there were ten increment #s for each 5 lb. No way can that work on this system; as the pole gets stiffer, the increments are less. Soft poles have a span of about 14 increments, each 5lb. And stiffer poles such as 14-185 5 increments per 5 lb. This is why most pole makers do not make 9'-45lbs poles or 14-210 poles because they don't understand this process. I was told at my previous pole brand, which I sold, that I was giving them the wrong flex chart. Yet they were engineers who needed a constant number. When they don't understand, you have to stop teaching them!

SOLUTION: Very SIMPLE - Only compare flex numbers between the same brand, not other brands. Pay attention here. When you go to the next length pole, there is a new span, except UCS and FiberSport use a progressive flex system. 12' same scale span as 12'7"- 13' same scale span as 13'7" 14' same scale span as 14'7" 15' same scale span as 15'7" and 16' same scale span as 16'5 & 16'9" length poles.

(PLEASE NOTE: Don't sweat the little stuff! The difference between 21.0 and 21.3 is one lb., and a 21.0 to a 21.6 is almost 2 lbs)

adjust your grip up or down in the grip area to average this! (1" = 1lb to 2lb depending on the brand)

For those engineers, it is .9887563354 Lbs to one-inch differential within the pole grip area LOL Holding is lower than the grip area, and the number is much greater, 2.2; lb per inch. One might think, "I can hold a foot below the grip area to make a 14-160 work at 180 load. A 160lb pole is a 161 load, and it cannot get stronger to move the grip down below the grip area. BNesided the bend curvature is a " C" that throws you fast at the bar, not over it.