Plate's effect on board?

[rjnakata]

37 minutes ago, David Kirk said:

I feel like anything bolted to the board will affect its flex pattern in one way or the other. The flex pattern of a board is tempting to look at in isolation but since it can't be used without bolting stuff to it I have to assume that board designers and builders factor the interface into the recipe.

I've been a bicycle designer for WAY too long and it's similar. People like to test bike frames/forks without it being in context. One can't ride a bike without wheels and the hubs bolt into the frame/fork and significantly change how, and how much, the parts flex under load. You get the idea....

Back to boards.....

With a rigid floating axle plate the location of the mounting points of the plate to the board will greatly influence how the board flexes in use.

With a flexible multi attachment plate like an Allflex I would think that the stiffness of the plate can be added to the stiffness of the board meaning the board will decamber less with a given load....and at the same time will will have less effect on the tip and tail (compared to the center section) as they are not directly bolted to the plate. Rider pedaling will also have an effect but not as much as with a non-plate direct mount.

Without a plate the width of the riders stance and the size of the binding foot print will do their own thing. We also need to factor in how much the rider pedals the board as it can be made to feel stiffer or softer depending on what the rider does with their feet.

 

dave

Given a plate changes flex pattern what flex modifications would you see beneficial?  stiffer nose, softer middle, not need as much torsional stiffness etc...

[Jack M]

5 hours ago, rjnakata said:

So my question: do plates (with bumpers, without, suspended, not suspended) modify board flex pattern to some extent?  If so, should the board be designed with a flex pattern to accommodate that?

It has been my experience that isolation plates like the Apex, Donek AF, Boiler allow the board to flex more freely, therefore more board flex is possible. I don't believe boards need to be built any differently for these plates, unless you wish.  Plates like the Allflex, Vist, and Vistflex (with center posts) alter the board's flex pattern significantly.  I have been told that boards are being built differently for use with Allflex.

[David Kirk]

1 hour ago, rjnakata said:

Given a plate changes flex pattern what flex modifications would you see beneficial?  stiffer nose, softer middle, not need as much torsional stiffness etc...

I think that is impossible to say.

I think it all depends on the baseline of what the board is like and then how it might be better if you want to 'fix' it with a plate.

It would seem that they can only be truly tested as a board/plate/binding/boot/rider system....and when you throw rider skill/experience and preference in all bets are off.

dave

[BlueB]

1 hour ago, Jack M said:

It has been my experience that isolation plates like the Apex, Donek AF, Boiler allow the board to flex more freely, therefore more board flex is possible. I don't believe boards need to be built any differently for these plates, unless you wish.  Plates like the Allflex, Vist, and Vistflex (with center posts) alter the board's flex pattern significantly.  I have been told that boards are being built differently for use with Allflex.

I totally agree with Jack on axle type designs. 

[SunSurfer]

One area that does need design change when a plate is to be used is the core strength around the threaded inserts. As plate insert patterns become longer, then the inserts are placed in progressively thinner core. Each insert creates a weak spot in the core.

My own experience of this is that in 2012 BV built me an NSR 180cm with standard binding inserts, standard UPM inserts, and then an extra pair of inserts 4cm beyond the UPM set at each end. I subsequently built a long interaxle design plate utilising these outer inserts and rode it. The board failed just at the front edge of the front outermost heelside insert. In the post mortem discussion with Bruce talked about the effects of inserts on core strength and what he'd learned since the board was originally built. Only a builder, like Bruce or Sean Martin, will be able to tell you exactly how successful they are at reinforcing the core at AllFlex pattern inserts, maintaining the core flex profile, and producing a durable board.

[lonbordin]

7 hours ago, SunSurfer said:

One area that does need design change when a plate is to be used is the core strength around the threaded inserts. As plate insert patterns become longer, then the inserts are placed in progressively thinner core. Each insert creates a weak spot in the core.

My own experience of this is that in 2012 BV built me an NSR 180cm with standard binding inserts, standard UPM inserts, and then an extra pair of inserts 4cm beyond the UPM set at each end. I subsequently built a long interaxle design plate utilising these outer inserts and rode it. The board failed just at the front edge of the front outermost heelside insert. In the post mortem discussion with Bruce talked about the effects of inserts on core strength and what he'd learned since the board was originally built. Only a builder, like Bruce or Sean Martin, will be able to tell you exactly how successful they are at reinforcing the core at AllFlex pattern inserts, maintaining the core flex profile, and producing a durable board.

I had a similar issue with UPM, a plate, and a metal board.  I know Bruce actually discourages inserts outside of the 4x4 system and will council against them.  There's a good argument against making holes in the core of a board so close to the edge.

[daveo]

8 hours ago, SunSurfer said:

Only a builder, like Bruce or Sean Martin, will be able to tell you exactly how successful they are at reinforcing the core at AllFlex pattern inserts, maintaining the core flex profile, and producing a durable board.

After lengthy discussions with Marcel over the past year in making my current Oxess and upcoming super secret board, I think I could add Marcel to that list safely.

Mr K... Well he's a secretive one... Although I did do an interview over email with him in like 2006ish or something, wish I still had it! 

[pokkis]

https://www.researchgate.net/publication/273823365_Mechanical_and_Dynamical_Properties_of_Racing_Snowboards_and_their_Modification_by_Different_Binding_Plates

[rjnakata]

Thread resurrect.   

I spoke with Jason Patel of Apex near the end of November 2019 regarding the X-Plate.  I had a few questions about installation and his answers in #3,4 were interesting in regard Apex's thinking on the bushing under the plate.  My questions with his answers follow:  

1) What is the "front" of the plate?  is it the square end or rounded end?

JP: The square end is the front and the round end is the back.

 

2) Should the floating mount be located in front?

JP: I call the mounts the "Slider mount" and "Pivot mount". The slider goes in the front and the pivot goes in the back.

 

3) The instructions say to relocate the bushings for goofy (I am a goofy), however the mounting holes don't seem to support this.  Is that correct?

JP: The relocating of the bushings applies more for the Allflex and UPM mounts  Of the 4 red bushings under each foot, 2 do most of the work of transferring the  load of your heal and toe to the board. The other 2 don't do as much. When we first came out with he plate people wanted as little to touch the board as possible so we only included the 2 per foot. However on the 4x4 version some people had incorrectly installed the bumpers or in one case not installed them at all and that lead to the mounts failing prematurely. So as a precaution we suggested having all 4 bushings and not removing them.

 

4) What is the role of the bushings?  Can (should?) the plate be ridden without them?  What might be the effect of that?

JP: No the plate should not be ridden without at least one bushing under the heel and one under the toe of each foot. The bushings connect the heel and toe directly to the edge of the snowboard and do it by rolling over the rubber edge of the red circle thus including a little bit more vibration dampening. Not using the bumpers will allow the board to bounce around under your feet and will also but too much leverage on the red aluminum mounts.