Will a standardized pole rating system work?

[Rocket Vaulter]

I am coaching a team of brand new jumpers and I ran into an interesting problem with respect to pole weight rating and pole progression. As the kids improve, they progress up through a series of progressively stiffer poles. Our pole inventoryis comprised of of UCS, Cata-pole, Pacer, Skypole, and Fibersport poles. We have a series of 13' poles starting at 120 lbs moving up to 150 lbs, 5 lbs at a time. The apparent increase in "stiffness" in moving from the 13x120 to 13x125 to the 13x130 seems to be right. However when moving from the 13x130 to the 13x135 lb appears to be 15-20 lbs as the kids go from blowing through the pole to not being able to make the pit (as if they raised their grip by 12".) The 130 lb is a UCS and the 135 is a Skypole.

It is always possible to mislabel a pole, but it seems unlikely to be the cause. The quality control coupled with the care used in cutting the fiberglass material means that what goes into the oven comes out as expected. The lack of a "standardized" procedure for determining the flex rating of poles means implies that the actual "weight rating" is arbitrary and is selected/defined by each pole manufacturer. Further it appears that it can't be standardized because different manufacturers have different sized sailpieces with different shapes and are located in different places to control the orientation and position of the top of the pole (i.e. the portion of the pole the vaulter grips.) as the pole bends and unbends. If material for two poles of the same weight and length are cut out and the only difference is the location of the sailpiece, when flexed those poles will come out with different weight ratings. This leads to the question: What criteria did the manufacturers use to be able to determine how to map ranges of deflection to weight ratings? What I would like to be able to do is to take all of the poles and "rate" them so at least I know the difference, as far as my flex tester is concern, between each pole.

I built a flex testing machine with the 50 lb weight and the fulcrums to hold the pole but I haven't been able to calibrate the machine and reproduce the flex numbers inscribed on my test pole, which leaves me stuck.

I have spent a considerable amount of time looking for flex charts and explanations which describes in enough detail, how their machines operate and are setup, and how the displacement data translates to a weight rating with no luck locating and information at all. It would seem that knowing what the pole distribution looks like with static weight has to be better than the current current model. Any thoughts on this? Again, my primary concern is to protect pole vaulters.

Any help that can be provided in obtaining flex charts used by each pole manufacturer would really be appreciated.

Thanks in advance,


Rocket Vaulter
UP, up and away!

[KirkB]

Any help that can be provided in obtaining flex charts used by each pole manufacturer would really be appreciated.

These charts would be quite useful to you if you can get them. However, I think your BIGGER problem is in determining the gaps between brands ... and possibly also in comparing poles of different lengths. I doubt that any manufacturers will disclose their flex comparisons of their poles with their competitors. You'll have to get that data from someone that's already done this ... or calibrate them yourself.

Incidentally, there's several threads on PVP that already warn against the futility of comparing poles of different brands ... exactly becuz of the other (non-flex) differences between brands that you're already aware of ... like sail piece design and hoop strength.

Regardless, I still think you're on the right track by personally calibrating comparative poles of different brands and different lengths. Calibrate them, using the identical fulcrums on both ... say 6" from the bottom and the same distance between the fulcrums (leaving a variable length above the top fulcrum).

You only need to worry about when the next pole up for a vaulter with a given grip needs a longer pole or a different brand pole. For each of these cases, you measure the next pole up AND the next pole down in the series.

Based on your own calibrations, you can then know with confidence that "a brand b1 13-0 pole has my personally measured flex of f1, whereas a brand b2 13-6 pole has a flex of f2" ... for example. (i.e. I would trust the official flexes of same-brand/same-length poles.)

Then, when a vaulter goes up a pole, he and you will know it's relative flex ... compared to if he went down a pole.

Obviously, the bigger the gap (and the more vaulters you have in that flex range), the greater the need to fill the gap with an additional pole (assuming one is available to buy).

I think you've already figured out most of this, so I apologize for stating anything that's already obvious to you.

Kirk

[rainbowgirl28]

Don't worry about trying to hit the manufacturer's flex, just get your own system in place so you can compare your poles. And even then, differences in sailpiece design could make one pole "feel" a lot stiffer than another, even if they are similar in flex number. Flex number is not the whole story (which is part of the reason a standardized flex system is not the world's most practical idea).

This is why it's best to stick with the same manufacturer when buying poles of the same length. You probably have a soft 130 Spirit and a stiff 135 Skypole. Also, if it's a really really old Skypole (like pre-1995), it might be before BestFlex. Also, SOME people think that SOME Spirit poles get softer over time.

[Decamouse]

Becca is right on -- few tidbits based on my experience and testing -- newer Spirit poles do not get softer with use - look at the Skypole (is it the darker green with black labels - check flex - if in inches - ie. low number under 15 - it was flexed in inches and is an old system - would be rated differently than if tested today - somewhere Jan J. has a chart that did a relative of pre Best Flex)

just another note - ASTM looked at some form of std and decided it would not happen plus the cost to the sport would have been - lets say - not a wise move

Cheers

[Divalent]

Your own flex measurements should allow you to calibrate your own poles, at least roughly, despite the brand and weight rating differences. Hence, you'll find out which are stiffer than expected, and where your gaps are. In my very limited experience (flexing about 15 poles this season), at least the older Skypoles ran about 10-15 lbs stiffer than other brands. (I borrowed a bunch of poles this season from various sources, and invariable when handed a Skypole the comment was something like "It says 130, but it's really more like a 140 or more"; and indeed when flexed the data confirmed their impression of how stiff it was.) (Kind of puts the lie to the claim that weight ratings are rigorously and precisely related to safety).

In constructing a table of what you got at different lengths, you might also find it helpful to also flex your longer poles at shorter lengths (e.g., also flex a 13' pole over the same span you flex a 12'-6, and again at 12'). This will give you a better picture of how the pole might operate if a vaulter needs more stiffness, but not necessarily the additional length.

BTW, I would be interested in seeing the data you generate, across different brands and lengths.

[ClintonMagus]

I am still VERY new to the pole vault game, but I have set up a simple flexing system in my garage (based on information from Earl Bell) so I can get a standard system of flex measurements. My daughter's coach and I looked through her poles (Altius, Skypoles, Spirits, and Mystics), got a basic idea about how she might progress through them, and flexed each pole at its recommended length, as well as at the lengths of the next two poles "down". This turned up some interesting results, but it does allow us to make more informed choices as she moves up.

[stylus]

I have had this problem as well. I had an 11’ 110lb and 130lbs Skypoles and both were BestFlex rated. I then got a 11' 120lbs Mystic pole, they were back ordered on Skypoles so I got the same flex in a Mystic, and it seemed a little bit stiffer than the new 120. I thought it felt about a pound stiffer and my vaulters just thought it was about the same, but the flex numbers didn't match up at all. So I called Gill and talked to Brian to see what they said. I found out that they, Gill, redid their flex system and the 110 was more like a 120. In fact the flex he said it was comparable to .1 lower that the 120. Which meant it would be a little stiffer. I tried to get a 120 label and they said I needed to send it to them and pay $50 to get it recertified if I wanted to get a 120 label.

The moral of the story is there is THREE, or more for the various brands, flex systems for Gill. The old, Best Flex and New Best Flex. Some time around 2003 Gill change how they flexed their shorter poles. So check the label, etchings, if it is pre Sep. 1, 1998 you can use the BestFlex relative Weight Chart to see where it would be. If it is BestFlex, but before the serial #'s, 2003, and 13' or under, it may be 10 stiffer than the label. You can call Gill and they may be able to tell you what the new flex would be. Compared to the New BestFlex system Pacer poles tend to be just a little softer than Spirit. But that is because of length, 12’ 1.5 vs. 12'

I also had a 12' 140 Mystic 2002 Bestflex rated, I called and they said it would be a 150 whith the new BestFlex system, I sent the old and new flex info for a new label and they sent me a 145 lbs label.

[Decamouse]

FIrst you need to compare apples to apples -- some poles where only offered in 10lb breaks - others in 5 lb increments -- so changes made would impact each differently -- second these where made in 2003-2004.

"The following details the adjustments in the current spans and flex number chart. This modification will be incorporated in the charts for the 1 September, 2003 change to -------

Span length Adjustment:
1. Currently poles from the 13’ (4.00M) length through the 16’ (4.90M) are flexed with fulcrums set at X” from the tip and Y” from the top end of the pole.
2. Poles 12’6” and shorter had an inconsistent pattern of top fulcrum placement. Additionally, the wider fulcrum spacing resulted in higher deflections which result in higher variances and increase the difficulty of consistent pole production for the pole room."

This is also the time ASTM was exploring the "possibility" of a National Standard -- if your system does not follow rational/good eng. principle - would be hard to justify

This is just a small inkling of why this is a little more complex from the anal eng. perspective - but from the coach- athlete - most HS and even college vaulters can not tell the difference of .1 or .2 in flex (we are not talking the elite) -- we at the lower end of vault efficiency have way to much inconsistentancy in our vault to make that type of true anaylsis and statement.

Changes can be made because your aim is to improve the accuracy or simple improve the system - or you can take the tack - well that's how it always has been done

From the HS rule aspect -- it did have a small impact in 2003-4

[rainbowgirl28]

The moral of the story is there is THREE, or more for the various brands, flex systems for Gill.

Only for poles 12'6 and shorter. Girls poles. Which makes sense because fiberglass poles have been made since the 60s or whatever, but girls only really started vaulting in the mid to late 90s, or even later in some areas. So it's taken time to develop the best system of length/flex/weight rating for the poles that girls most commonly use.

If I were a dealer, I would never sell someone a pole without first finding out what they have. They can tell by the flex numbers if a pole is under the old flex system or the new, so whoever sold you the 11'120 probably should have put in more effort to make sure that what you were getting was actually what you needed. IMO.

[Decamouse]

well said -