# Board Flex Ratting



## mallrat (Oct 27, 2009)

Previous board was an '01 Lib Tech Jamie Lynn and current an '09 Uninc 159

Jamie Lynn (6.5)
Uninc (5)


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## snoeboarder (Sep 19, 2008)

whats the basis though ... if mr x has ridden 10 boards total and mr y has ridden 5 total ... there is a better chance mr x will rate it one to two points differently because he has more to compare with

the number is relative only within the same company to be truly accurate


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## DC5R (Feb 21, 2008)

This is a good idea, but I'm not too sure how this should work. What are you rating your board flex against? There needs to be some standard to base your flex on. As an example of how this could vary so much, if I think the Signal Park Rocker is a 4, would the Agent be an 9?


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## DC5R (Feb 21, 2008)

Dammit...been ninja'd


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## mallrat (Oct 27, 2009)

I'd just go on your own opinion. Someone will find some combarable and then be able to equate that way.


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## crazyface (Mar 1, 2008)

Lib Tech TRS (7)


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## BurtonAvenger (Aug 14, 2007)

Board flex determined by a bunch of guys hand flexing in a shop saying it feels like a 6 no it feels like a 7 ok we'll rate it a 6.5


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## earl_je (Oct 20, 2009)

signal park rocker - wet noodle 
skate bananer - 4x4 
NS evo-r - tupperware


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## legallyillegal (Oct 6, 2008)

flex ratting

as in ratting out teh lies

haha they said the WWW was a 3 but it;s actually a 2 haha


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## twin89 (Jan 21, 2009)

There should really be a standard measurement for board flex, like the amount of Work required to flex the center of the board 1 inch from its resting point.


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## MunkySpunk (Jan 7, 2009)

DC5R said:


> This is a good idea, but I'm not too sure how this should work. What are you rating your board flex against? There needs to be some standard to base your flex on. As an example of how this could vary so much, if I think the Signal Park Rocker is a 4, would the Agent be an 9?


QFT. Numbers are meaningless without a frame of reference. Chunky the Human Beanbag and Stretch the Human Beanpole each have the same board. Chunky's going to rate it much flexier. And who's to say Chunky's 5 doesn't mean my 9?



legallyillegal said:


> flex ratting












twin89 said:


> There should really be a standard measurement for board flex, like the amount of Work required to flex the center of the board 1 inch from its resting point.


Good luck.


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## Tarzanman (Dec 20, 2008)

That still might not tell you much because some materials don't have linear/constant spring constants (meaning that even though 2 different boards might flex 1" under the same force, the force required to push them to a 2nd inch might be different.

How do you know that the "6/10" or "7/10" flex value isn't an inverse of the spring constant or something? Anyone wanna test it?


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## kingkoajmr (Nov 12, 2008)

twin89 said:


> There should really be a standard measurement for board flex, like the amount of Work required to flex the center of the board 1 inch from its resting point.


I agree with you. They do that with hockey sticks. Most companies make an flex of 85ish, 100ish, and 110ish. I believe the number represents the amount of weight suspended from the midpoint to get one inch of deflection. I think a system like this would help riders make a more educated choice on purchases.

This would obviously only account for longitudinal flex. Torsional would be a whole different issue.


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## walove (May 1, 2009)

im working on a project like this right now. I have access to extensionometers (big force and distance measuring machines) I plan to test longitudinal and torsional flex for the tail, mid, and tip sections. Use the data to create a meaningful flex scale. I want to test new boards and used board to determine how fast and where boards break down. It'll won't be done until sometime this summer, but i'll keep you posted as it goes along.


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## Tarzanman (Dec 20, 2008)

No need to do all that! All you really need are two stools, some weights and some rulers.

If you want to be uber-high tech then you can use some laser levels!

The problem you'll run into is how to compensate for different board lengths and different cambers.

There are ways to make it more complicated.... but what most people care usually care about is how much the middle of the board will bend when put under strain where the bindings are attached.



walove said:


> im working on a project like this right now. I have access to extensionometers (big force and distance measuring machines) I plan to test longitudinal and torsional flex for the tail, mid, and tip sections. Use the data to create a meaningful flex scale. I want to test new boards and used board to determine how fast and where boards break down. It'll won't be done until sometime this summer, but i'll keep you posted as it goes along.


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## walove (May 1, 2009)

Tarzanman said:


> No need to do all that! All you really need are two stools, some weights and some rulers.
> 
> If you want to be uber-high tech then you can use some laser levels!
> 
> ...


I work in a lab at school an have been talking to some experts and they tell me that i can mount the tail firm and flex the entire board to a specified distance. Then uses a mounted camera to measure deflection in the tip mid and tail. I can then perform one test to get all three values. Same goes for torsion. Im working on the rig now, figuring the best way to mount the tail so it won't move at all but still does not effect the flex. I think i am going with two round bars wrapped in rubber to clamp the tail and mount that to a big steel frame with room for counter weights if needed. 

as for different lengths, i will be measuring valus for the tip/mid (center of inserts to center of inserts)/tail. It will be up to people to interpret the data for different lengths. (longer board with the same strength will feel stiffer) But this will allow for someone who wants a board out of their weight range to get a actual value. Not a suggested value for an ideal rider.

As for rocker. I will be flexing the board much past the rocker profile, and imagine the strengths here will be similar for both rocker and camber. If you look at the strength curves though the rocker boards will return a negative value until it reaches its natural shape and then increase as it is flexed past that point.


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## leif (Dec 10, 2009)

Nobody has mentioned yet how different boards flex due to the rider weight. My Nitro swindle 152 has about a mid flex to me (150 lbs), but when my buddy who is 180 straps in he can flex it way more. 
You'd have to make sure that everybody the proper board size in order to have a 'universal scale.' Otherwise youd have to assign every board size in every company's line up a specific number, like the hockey stick idea.


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## kingkoajmr (Nov 12, 2008)

leif said:


> Otherwise youd have to assign every board size in every company's line up a specific number, like the hockey stick idea.


For each inch cut of a stick you add approx 5% stiffness. 

I understand that the tech is very different and snowboards have a variety of camber options, but I wonder if walove's research will reveal something analogous. If so, companies could say something like their 158 has a flex rating of blah blah blah and for every 3cm shorter/longer the flex decreases/increases by thusandso%. With every company having their own take on camber/rev. a companies flex rating might only be comparable to their board line and not another companies line. Which already achieved by the current rating system.


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## walove (May 1, 2009)

im looking to get hard data for each board that then each rider can interpret it for their own weight, and mostly compare between boards. As for board length (this might change once i get data) if i get a strength number, i can divide it by a unit lenght to get a standardized value. Snowboards are relatively close in size, the difference between a large to small board for one person are probably within 10% of total length, so i am not convinced that length will be a big factor.


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## c1rca491 (Dec 11, 2009)

What if they determine flex by a frequency. Like set up a board on a machine moves linearly at a constant rate and measure the frequency that the board flexes at and some how come up with a scale. Riders weights wouldn't matter because its all for reference compared to other boards. Just make sure when your comparing boards they they are the same length


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## walove (May 1, 2009)

i believe a finding a fundamental frequency and resulting range of motion would give you a information about the livelyness / dampness of a board. Its an important characteristic but a lot can assumed about dampness from the construction technique and core used in the board. I would like to work with one test and perfect it.


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## banana420 (Dec 7, 2009)

i think it really depends on the flux capacitor.... lets be realistic here there will never be a general board flex rating between different companys.


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## Triple8Sol (Nov 24, 2008)

Nobody likes a rat.


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## walove (May 1, 2009)

banana420 said:


> \ lets be realistic here there will never be a general board flex rating between different companys.


not between or even with companies. This is to be a completely second party test. No bias no hype, just hard numbers. Gatering the boards to test is the biggest issue. Im working with shops in town to put some new shapes through the test. Will every board be in my test, no but i hope to make the rig simple enough that any student at a university with access to a extenionometer (pretty much any engineering student) could replicate the test and get quanitfiable numbers.


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