Allflex thoughts

[Comapedrosa]

15 hours ago, Jack M said:

Welcome to the club, @Comapedrosa.  IMO it is THE board.  Also IMO, the ultimate plate for it is the Apex X-plate.  But it's not required.

@Jack M, some make it sound like the Apex X is old, out of production and way obsolete . I know that you tried and didn’t like the Allflex in this board. Before I commit to this “older” plate, how should I think about the Apex X? Is it still in use? What’s different about it?

[Jack M]

19 hours ago, Comapedrosa said:

@Jack M, some make it sound like the Apex X is old, out of production and way obsolete . I know that you tried and didn’t like the Allflex in this board. Before I commit to this “older” plate, how should I think about the Apex X? Is it still in use? What’s different about it?

Well, it is based on technology that won the 2010 Olympics.  Racers have since moved on to the Allflex.  The X works great for freecarving. I tried a GS Allflex on my 168 and really didn't like the feel.  Probably the wrong combination, but it was all I had available.  The X and Allflex work completely differently.  The X allows the board to bend freely apart from the rider, unlimited.  The Allflex only allows 6mm of "float" before the plate locks up and then flexes with the board.  So it is a big flex modifier and makes boards run longer.  Mechanically, I don't understand it, but what do I know?  Apparently you cannot be competitive in a race course without one.  Also I'm told WC racers are cracking or breaking multiple plates each season.

[TimW]

On 1/7/2020 at 2:20 PM, Jack M said:

Well, it is based on technology that won the 2010 Olympics.  Racers have since moved on to the Allflex.  The X works great for freecarving. I tried a GS Allflex on my 168 and really didn't like the feel.  Probably the wrong combination, but it was all I had available.  The X and Allflex work completely differently.  The X allows the board to bend freely apart from the rider, unlimited.  The Allflex only allows 6mm of "float" before the plate locks up and then flexes with the board.  So it is a big flex modifier and makes boards run longer.  Mechanically, I don't understand it, but what do I know?  Apparently you cannot be competitive in a race course without one.  Also I'm told WC racers are cracking or breaking multiple plates each season.

Theoretically a progressive board stiffness does make sense, and the plate locking up does provide that in a very rudimentary way. On your small radius 168 it will lock up much earlier than on a GS board, probably too early for freecarving. 

The allflex aluminum construction with the milling on the bottom will be prone to fatigue failure if it flexes significantly, that probably explains breaking plates.

 

Edited January 12, 2020 by TimW
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[Jack M]

53 minutes ago, TimW said:

Theoretically a progressive board stiffness does make sense, and the plate locking up does provide that in a very rudimentary way.

But not truly.  The plate cannot affect the flex of the board beyond the length of the plate.  This is the problem I have with it.  The flex pattern of the board+plate combo becomes a three-part disjointed thing.

There was a picture on social media from someone who installed Snow-Stix at the ends of their Allflex in order to address this issue.  They're on to something.

I think the ultimate solution has yet to be discovered.

[TimW]

8 hours ago, Jack M said:

But not truly.  The plate cannot affect the flex of the board beyond the length of the plate.  This is the problem I have with it.  The flex pattern of the board+plate combo becomes a three-part disjointed thing.

There was a picture on social media from someone who installed Snow-Stix at the ends of their Allflex in order to address this issue.  They're on to something.

I think the ultimate solution has yet to be discovered.

Yes fully agree. And since allflex is now making this plate with springs I think they agree too

Still this will give two stages in the boards behavior, with springs activated beyond a given (6mm?) flex. Something continuous feels better to me. 

However I think there is also a lot to be gained in the stiffness distribution of the board itself, especially for boards with plates. Having the stiffest section in the middle, between the pivot points, where bending moment is low, does not make sense to me at all.

[Jack M]

9 hours ago, TimW said:

Yes fully agree. And since allflex is now making this plate with springs I think they agree too

Still this will give two stages in the boards behavior, with springs activated beyond a given (6mm?) flex. Something continuous feels better to me. 

However I think there is also a lot to be gained in the stiffness distribution of the board itself, especially for boards with plates. Having the stiffest section in the middle, between the pivot points, where bending moment is low, does not make sense to me at all.

 

Agreed as well.  The spring plate seems like an admission of the fact that the one piece plate does weird things to the board.  The fact that they are successful in racing I think is a happy coincidence.  I'm not sure Allflex themselves knows why they are - the description on their website of how the plate works bears no resemblance to how it actually works.  Maybe that is on purpose to protect trade secrets?  But again, I haven't spent enough time on one.

It would be one thing if boards were made as you said, to work with the plate, with the stiffest parts near the ends of the plate instead of in the middle.  Maybe world cup racers get custom boards made this way?  I got a new stock Kessler 185 with Allflex inserts this year.  Seems like a traditional board.  I haven't ridden it with an Allflex plate yet, but it works great by itself and with my Apex plate.

Last year a picture was leaked of a carbon fiber Iron Rock plate.  That would make more sense to me, but again only if the board was built differently to work with it.

[TimW]

I have never posted much on how I design my boards (because as a wiseguy amateur builder I do not want to end up in discussions with people who make a living out it, and because I am still not fully decided yet if I ever want to go professional myself), but I will give in to the temptation (a bit).

I design my boards to have a specified pressure distribution along the edge. Below my starting point for a board with a plate, based on a 700mm pivot distance (similar to apex, bit shorter than allflex I think). Blue the edge pressure, orange is the interface points pressure(to match).

 

This pressure distribution is for a certain turn radius and with that I calculate the required core stiffness and thickness to achieve that . 

The result is below.

You see that with this approach you end up with a very thin core in the center (~4.5 mm, vs 8 mm at the thickest section). This is for a 1740mm effective edge, which was about the shortest I felt I could get something usable with with this approach. (With shorter eff. edge it quickly goes to zero thickness in the center)

In the end I changed my approach to a less uniform pressure distribution, also to get a bit progressive stiffness character (percieved, not actual), but it gives some insight into what a plate does. 

With a conventional core thickness the thickest part is between the pivot points. Since the bending moment is highest at the pivot points and can only be lower in between, this means that the edge will actually have no pressure at all in the center of the board, but be up in the air. (on a flat hard surface).

 

Edited January 14, 2020 by TimW

[pokkis]

I have Allflex H-type on 168 and it works fine, it is also lighter for my poweless legs