how to measure the flex of a board

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Dave
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how to measure the flex of a board

Post by Dave » Tuesday 23 November 2004, 15:39

Hey

I was wonderring how people know when a board has a hard or a soft flex?!

dave

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vkrouverk
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Post by vkrouverk » Tuesday 23 November 2004, 21:24

By experience or comparing their flex directly?
One possibility is to measure BOBSI and compare it with other boards. Unfortunately old Bomber forum which contained data for different board's BOBSI is unavailable, but if you have access to different boards and want to use 'scientific' approach instead of bending boards by hand then it might help....
Converting potential energy to kinetic..

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skywalker
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MHO

Post by skywalker » Wednesday 24 November 2004, 10:11

Hi,

I think, measuring overall flex of a snowboard is rather useless. It might give one a comparison, which boards are harder than others, but it won't answer the question which board fits me perfectly. To answer this, you need the contribution of the flex, which might be given in a graph. In this way you could detect a for example rather soft board with stiff nose.

Usually flex comparison is done by pushing a board by hand. With some experience, you can see the bend curve of the board, feel the flex of the nose, feel the response. All this will give you a hint how a board m i g h t behave. The more boards you have felt and the more you know about the board in your hands, the better the estimation will be.

On the other hand it's quite interesting to bend a board that you have ridden and try to find explanations for that, what you have felt during your ride.
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Post by tigger » Wednesday 24 November 2004, 14:02

bobsi..... sounds funny, but made me curious,
as i have some boards by the hand( kingpaddels and mine) i tested some.
the results might be a bit incorrect due to incorrect measurement and uneven floor but the differences are less than 5% i guess. the results seem to be right compared to each other and with my felling.
the results:
hot blast164 (1997) 10,3
trans FE160(middleages) 8,7
nitroGT160 (?1996) 9,1
völkl RT163 (?99) 8,7 (mine 77kg after 25days!!)
völkl RT163 (?99) 7,3 (Kingpaddels 85kg after 30days!!!)
speedsterRS164 (?95) 9,6
F2 speedride170 (04) 10,0
nitro titanium 159 (00) 8,9 (my old freeridecucumber)
POGO 164 1998 12,2
virus gladiator 04 13,8
...seems to make sense, although i think skywalker is right.
specially the renntigers are totally worn out after three weeks they kept wobbeling a minute after i loaded the 10Kg to measure :lol:
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frunobulax
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Post by frunobulax » Wednesday 24 November 2004, 14:26

Interesting.
Higher numbers mean stiffer board?
What is F2 Speedride? Have I missed something?

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Post by tigger » Wednesday 24 November 2004, 14:34

the speedride is paddls freerider 26cm wide for thepowderdays
like the new speedcarve
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skywalker
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Cool

Post by skywalker » Wednesday 24 November 2004, 17:03

Useless or not: I love this ranking!!!
I have a Trans Fe 155 for my SB-Students, it's not that bad for the first days. I think, they learn it better with a not totally soft and short board and with Hardboots.

Funny to see, that the Gladiator is that hard. I've estimated him stiffer than a Nitro GT for example, but not that much more than the Blast. No surprise is the stiffness of the F2 Freerider, they often are quite stiff, as the eff. edge is rather short.
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pokkis
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Post by pokkis » Wednesday 24 November 2004, 17:30

I dont remeber anymore, getting old :D , BOBSI spec but was it so that one can only compare relult number of board to equal length board.
That is way, if i remember correctly, with stiffnes number of Donek's.
It would be intersting to see numbers for all 9 different Swoards too :)
anyone have full set ?
How long is Gladiator ? I could not find spec from Virus site.

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Post by tigger » Wednesday 24 November 2004, 17:44

...the formula is:
(98.1/X)x(effectife edgelenght x effectife edgelenght)
x= the height difference of the camber in cm when you load your board with 10kg weight
the board must attached at the end of its eff. edge..
too difficuld for my english, please look at vkrouverks link
it says the donek stiffness index is something different as the scale reaches up to 10 only
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Post by tigger » Wednesday 24 November 2004, 17:56

pokkis, the gladiator is 175 if i measured correctly, it is a bit difficuld to measure the edgelenght either, so dont take these numbers as proofen, :wink:
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skywalker
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Gladiator

Post by skywalker » Wednesday 24 November 2004, 18:05

As i am the Virus-guy anyways:
The Gladiator is missing on the Virus-HP, but regarding to the Virus-Catalogue 2004/2005 the length is 175. Eff. edge is 157 and waist width is 17.1.

Did I get you right?: You lay your board down touching the ground only at the nose and the tail end of effective edge. Then it is loaded with 10Kgs in the middle of the board and the vertical movement under the weight is measured?
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Post by tigger » Wednesday 24 November 2004, 18:15

...i layed 2 beams on the floor with the measured distance of the eff.edge, and put the board ontop. then i measured the distnce to the ground before and after i put the weight on. the difference is x.
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roman
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gladiator

Post by roman » Wednesday 24 November 2004, 18:17

i know, that has nothing in common with this tread. 8) .. anyway, i love the gladiator! :clap2:

ride on!

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pokkis
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Post by pokkis » Wednesday 24 November 2004, 19:03

Ok, thanks for G info.
I was expecting it be much shorter due:
Unsere absolute Überwaffe für das Duell auf der Piste!
cause i was thinking, as old man, Duell as PSL :oops:
So it looks to be quite stiff stick :D

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roman
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Post by roman » Wednesday 24 November 2004, 20:24

mhmm. :oops: .. now shame on me, what means PSL :think:

by the way, the gladiator is way stiff. but the flexcurve is really big. means, you can go as fast as your legs can hold on to, or carve in slower velocities and do some really small radius vitellis.

ride on!

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