UPM Plates and Centering Bindings

[ktv]

What is the center point on a board just with just UPM inserts in order to center the bindings?

I assumed it was centered with the inserts, but found this thread with a drawing of the UPM inserts.

 

My insert measurements don't match the measurements in the drawing in that thread. My closest set of inserts center to center are 480 mm, and the farthest apart are 660 mm. The spacing between the sets of inserts is still 30 mm.

With the different measurements versus that drawing, is the center now truly centered on the inserts?

The board is a JJA if it makes a difference.

Thanks,

Khanh

[barryj]

3 hours ago, ktv said:

 

Hey KT

Hmm....

3 hours ago, ktv said:

What is the center point on a board just with just UPM inserts in order to center the bindings?

Hey KT         

Not sure I understand that question?....are you just trying to center your bindings??   If so don't even take in to consideration the UPM inserts. Use the standard mounting inserts and just average your placement based more on your splay measurement... the distance/measurement between your bindings center to center. I think the norm these days is around 20-22 inches between bindings 

All I know is Jasey has a proprietary UPM setup... you have to buy/use his JJA isolation plate, the attached plate and the bindings on the plate would be how/where you could set center or more forward to weight the nose or more behind center to weight the tail.....but your splay would be the same no matter where you centered/mounted your bindings. 

 

[Corey]

Fin mentioned that the pattern was originally offset rearward relative to the 4x4 inserts, but it was later centered on the inserts as most people wanted the front axle further forward. 

[barryj]

12 minutes ago, Corey said:

pattern was originally offset rearward

I believe Corey's referring to the hole pattern on Bomber BP Plates....but either way, according to Jasey J. himself,  a Bomber BP Plate will not fit the UPM hole pattern on any JJ board....only a JJ plate will fit a UPM JJ board.  

[SunSurfer]

14 hours ago, barryj said:

I believe Corey's referring to the hole pattern on Bomber BP Plates....but either way, according to Jasey J. himself,  a Bomber BP Plate will not fit the UPM hole pattern on any JJ board....only a JJ plate will fit a UPM JJ board.  

I thought the U was supposed to be Universal not Unique!

[barryj]

8 minutes ago, SunSurfer said:

U was supposed to be Universal not Unique!

Yeah.....that's what I thought also but Yami had a JJ board  here in the classifieds with what looked like UPM I was interested in and so I asked Jasey himself.  He said it's based on UPM but offset so only his plates will fit...........so call it a JPM,  I guess! 

[ktv]

I'm asking how to know where the center point is to center my stance width.

On a 4x4 board, I begin centering my stance width centered between where the front and rear inserts measure equal distance. Mount the stance farther forward than this, and the board initiates turns quicker. Move it more rearward, and the board reacts slower to turn. This board only has the UPM inserts, so I can't use the 4x4 from the board as reference. 

I assume in riding a plate it's the same. I want my stance centered on this same point, otherwise it'll impact how the board handles.

It sounds like from Corey's response that it is indeed midway between the UPM inserts.

The photo shows how I centered it before seeing the diagram that has the center as offset and questioning the center.

The blue tape on the board is the midway point between the UPM inserts. The blue tape on the plate is the midway point between the 4x4 inserts on the plate.

[barryj]

2 hours ago, ktv said:

center point is

Even on a plate I'm more concerned with:

1-  my splay is the same as on other board+plates                                                                                2- I've done the fuego  test to prevent any boot out                                                                              3- My angles are set to match my other boards   

Last, and least critical to me,  I'd just eyeball it and move both bindings to visual  center of the plate inserts. 

Lay a tape measure (or string or cord cut to the splay length) on the plate at the splay length and you can see/move the tape/string forward/backwards to see what looks center.  As a nose stomper I go more  1 set of inserts more forward, even on my plates....while keeping my splay the same

 Ezy-Peazy............ride and adjust as necessary.................. 

[SunSurfer]

@ktvYYour photo shows the axles of the plate are mounted under your bindings. Having the axles at least slightly outside the centre of each binding means you won't feel like you're riding on a diving board.

The further the plate axles are apart, the greater the length of board midsection that has its torsion resistance increased.

The further the axles are apart, the less the board will flex along its length under turn loading for a rider of any given weight.

 

 

[ktv]

Hey Alan,

I actually found a pdf that I believe you posted on one of the plate threads with instructions from Jasey Jay on mounting his plate. In it, and I saw that it says the closer together the axles, the softer the board feels (to a certain extent). I'm going to try it in multiple positions and intend to adjust to get a feel for where the axles are located and how it impacts the board feel. I'm starting this way intentionally, especially since I'm lighter in weight. 

It hasn't been cold enough here in Ohio to have a reasonable amount of snow, so I haven't tried the board yet.

[SunSurfer]

The plate takes your mass and transfers the points at which it is applied to the board to the axle positions. If all your mass is placed in the middle of the board then the maximum flexion occurs. If the axles were at the very tip and tail of the board there would effectively zero deflection.

Having the front axle under the ball of your front foot and the rear axle equidistant from the effective edge centre is probably the minimum functional interaxle distance. Any shorter and you'll likely start to feel like you are on a diving board with your front foot. By all means experiment with going longer and shorter, gain your own personal experience, and see what you prefer.

You could also try putting the non-sliding axle under your front foot. Conventional plate setups put the sliding axle at the front, but the plate still allows the board to flex freely with either orientation.