How are/were weight ratings established?

[lonestar]

We all know that poles have both a weight rating in lbs. and a flex number. A weight rating is assigned to the pole based on the flex number. Example: a 15' with a flex range of 17.1-17.9 is assigned a weight rating of 175lbs. The 17.9 would realistically be more like a 171lbs while the 17.1 is more like a 179lbs. (not sure if these numbers are exact, but just as an example)

My question though, is who determined that a 17.3 corresponds to a weight rating of 175lbs, and how was that determination made? I'm sure it wasn't an arbitrary guess, but I'd like some rationale for why a manufacturer says that a 17.3 flex should theoretically only hold a 175lb vaulter.

Also, back in the day, ThermoFlex and I believe Browning Silaflex Skypoles had the handhold to weight rating conversion charts on them. For example, on a 14' pole, holding 14' might have had a 170 rating, holding 13'6 a 180 rating, 13'0=190lbs, 12'6=200 and so on. Why did the manufacturers get away from that?


Bruce, Bryan, Jan - your thoughts please!

Kris

[jhesch]

this is somewhat off topic. nonetheless, im curious as to whether or not any pole manufacturer would consider getting flex numbers a little bit differently. it is my understanding that manufacturers determine flex by placing a designated amount of weight (uniform for all poles), and measuring the displacement of the bend of the pole. because it is uniform weight, a pole designated for much heavier weight would always seem stiffer comparatively, when in fast, it's possible for two people, one light and one heavy, to have the same speed, and the heavier pole is respectively softer. its kinda hard to phrase what im tryin to say. nonetheless i assume several of you will know what i'm talking about. why don't they instead put 10% of the pole's designated max weight as the amount to measure the flex number. therefore, every pole could correspond respectively to whether it could be considered soft, medium, or stiff. i.e. a pole for 100 lbs, measured w/ 10 lbs, might flex X inches, when a 190 lb. pole. measured w/ 10% of ITS weight (19 lbs.) flexes X+3 inches. in this case though the poles are made for different weights, they could be labeled as soft, medium, or stiff. this way it would be much easier to set a standard for which to compare the pole's flex number, and match it almost solely for speed instead of having to look at flex number w/ regard to weight, speed, skill, etc. just a thought, tell me if anybody has any other ideas, comments, and if any manufacturers do this.

J jhesch@earthlink.net

[Bruce Caldwell]

Does the flex number determine the weight of the pole, not entirely?
As there is no published scientific research on this matter. We have as manufacturers used what we have learned over the years from extensive trial and error. We are talking about over 40 years of fiberglass pole manufacturing with HERB JENKS the father of the fiberglass pole doing most all of the research. From a point defined, as the design and flex of a pole to sustain success, for a given weight, and speed of the normal vaulter.
And factors built in to allow for variances.

The flex charts we at ESSX use today are a compilation of poles used in the field by Skypole, Catapole, Accelerator, Altius, Maxima4 and Fibersport.

Yes, I will admit that a 155 weighted vaulter could use a stiffer pole and one must understand that the flex chart is a means for establishing consistency when producing poles, it is not a method to tell one that this flex number will hold a certain weighted vaulter.

A manufacturer can make a pole with as you say 17.1-flex number and it could never hold a 179 lbs vaulter. PS it is 460/80 176 on our chart.

What people forget is it is the pattern design that makes the pole the weight rating it is.

The amount of wraps, the diameter, the taper, the technology and experience the maker has and places into the implement. Vaulting experience plays a big part of how a pole is made; you must understand the vault to produce the best pole.

We are not saying that a 17.1 flex will hold a 176 lbs vaulter we are saying that our pole with its design and a 17.1 flex will work as a normal stiffness for the average 176lbs vaulter.
It Is way more than stiffness, it is tensile strength, flexibility, the way the pole bends over, memory, the weave of the glass the resin content, what temperature and pressure is used and what times are set for curing, etc.

So what seems to be in question here is flex numbers by themselves do not support the weight rating a manufacturer is placing on the pole?
You are right because it is more than the flex number.

[Bruce Caldwell]

Also, back in the day, ThermoFlex and I believe Browning Silaflex Skypoles had the handhold to weight rating conversion charts on them. For example, on a 14' pole, holding 14' might have had a 170 rating, holding 13'6 a 180 rating, 13'0=190lbs, 12'6=200 and so on. Why did the manufacturers get away from that

Yes Skypole use to use a sliding scale of weight ratings in the handgrip area.

After many abused it, selected the pole based on a lower handgrip and then raised it when the adrenaline was flowing and it was zero hour to clear the bar.

You see a pole has a sail in it see
http://f2.pg.photos.yahoo.com/ph/essxsp ... ph&.view=t

[color=blue][b]This sail size increases or decreases the pole flex by the amount of wraps it makes on the pole.
It does not re-enforce the grip area.
If you took the sail out and in order to make that size pole we would have to wrap a full length wrap of glass equal to the sail. You would have a thermoflex brand pole, as they were not made with sail pieces. With this design pole you could have a variable weight. It would be consistent per inch. But if you try to do that with a sail piece type design you will have far to many variables that will work against this type weight rating especially if you allowed a larger person to use the pole holding lower and then they decide to raise the grip at the end of the runway.

I can hear it now I weigh 180 on a 160 test and the pole on the 2nd jump broke and I was holding where I was supposed to one foot down!! Far to many poles would break due to no control of proper usage.

As the pole makers started making better high school poles the variable of weight became a variable of timing within the grip area and the poles have actually become better rated to fit the vaulters in the past 3 years.

Further comments:

Picture a pole with a sail piece; holding low would allow you to have a stiffer entry at the plant and it will hold a larger vaulter, but would a 10lbs bigger vaulter holding 1 foot lower get the same pole reaction?

Would the pole’s memory come back with the same angles of flip?

If the pole was made for variable weight would it work the same for variable weighted vaulters?

NO there is no way it can react the same for different loads and different handholds


I feel there is the need for a variable weight pole in the 11’6â€Â

[Bruce Caldwell]

this is somewhat off topic. nonetheless, im curious as to whether or not any pole manufacturer would consider getting flex numbers a little bit differently. it is my understanding that manufacturers determine flex by placing a designated amount of weight (uniform for all poles), and measuring the displacement of the bend of the pole. because it is uniform weight, a pole designated for much heavier weight would always seem stiffer comparatively, when in fast, it's possible for two people, one light and one heavy, to have the same speed, and the heavier pole is respectively softer. its kinda hard to phrase what im tryin to say. nonetheless i assume several of you will know what i'm talking about. why don't they instead put 10% of the pole's designated max weight as the amount to measure the flex number. therefore, every pole could correspond respectively to whether it could be considered soft, medium, or stiff. i.e. a pole for 100 lbs, measured w/ 10 lbs, might flex X inches, when a 190 lb. pole. measured w/ 10% of ITS weight (19 lbs.) flexes X+3 inches. in this case though the poles are made for different weights, they could be labeled as soft, medium, or stiff. this way it would be much easier to set a standard for which to compare the pole's flex number, and match it almost solely for speed instead of having to look at flex number w/ regard to weight, speed, skill, etc. just a thought, tell me if anybody has any other ideas, comments, and if any manufacturers do this.

J jhesch@earthlink.net

This is an interesting concept, however you are using a weight rating to set the flex number.
I applaud the possibilities and I will study this idea further as it might have some merit. When I look at what number we get using this and then moving to the next size length, I do not get what we strive for a consistent curve in the charts.
It is kind of reverse and the method would again require trial and error testing in the field for another 40 years grin.

[Bruce Caldwell]

The flex method I chuckled at was the thermoflex method;

Where you place the pole on two chairs I think about 2 feet on each side.

You sat on the pole inthe center and if it did not deflect more than 1 foot the pole would fit you.

It had some merit, but was not a consistent method.

[vaultfan]

ESSX wrote:

"The flex charts we at ESSX use today are a copulation...."

Hey Bruce!! Now that's a graphic description of flex charts!!

[Bruce Caldwell]

ESSX wrote:

"The flex charts we at ESSX use today are a copulation...."

Hey Bruce!! Now that's a graphic description of flex charts!!

GRIN your right

Compilation