TD3 SI mod for Increased Forward Boot Bias

[rjnakata]

TD3 Step-In mod for increased forward boot bias

Problem: With existing bindings I have not been able to align my UPZ M26 boot toes/heels their adjacent board edges.  This is especially acute at the front boot.   Available bindings place the boot biased toward the back of the binding.  If the heel is aligned with the adjacent board edge (using a square from edge to heel) I get roughly 1/2" to 3/4" distance from boot toe to adjacent edge.

My typical angles: +/- 60*/55*,   6*/3* , no cant - lift only.

Here is a modification I used and tested one day only with no observed ill mechanical effect.  This is what I did at my own risk, if you do something like it please do so at your own risk.  I would love your feedback.  If there is one thing I know about Alpinesnowboarder members is that there is a lot of experience, creativity, and technical know-how here.   Please share your concerns and ways to improve!  

 

FRONT BINDING BEFORE: TD3 SI rear receiver moved forward maximum distance.  Front block secured to middle of 3 sets of holes. BP cant discs shown.  (Regular TD discs can also be used with this mod)

 

FRONT BINDING BEFORE: approx 1/2"  rearward bias illustrated with boot center.  This yields 1/2" - 3/4"  of distance from boot toe to adjacent edge with my small radius boards.

 

[edit]: FRONT BINDING BEFORE:  55* angle w/ 6* lift.  20cm width board.  0" underhang at heel,  5/8" at toe.

 

MOD PARTS: If NO CANT (pure lift on toe or heel) is used (2) M8 threaded bores are exposed.   I widened the outside edges (in red) of the receiver slots to accept M8 screws.  This was the hardest part given my rudimentary metalworking skills.  I used a carbide reamer with a hand-held drill, a file and some clamps. Approx 1.5mm was removed left & right.  SS washers were modified with an angle grinder.  Although I illustrate for the front binding the M8 holes also appear at the rear binding (with no cant) so this could be done there as well.

 

 

ASSEMBLED MOD: The receiver  moves forward approx 1/2" (along with the corresponding toe block).  I added extra bolts to the baseplate/cant disc connection for well just because.   [edit]: Longer M8 screws could be used with a regular TD cant disc for greater thread penetration.  The mod works for TD & BP  cant discs FRONT & REAR binding.

 

THE MOD: The small washer (above the large cut washer) is used to modulate the M8 screw depth.  I want maximum penetration into the cant disc (without over-penetration into the board) especially since the disc depth is minimum at the low side of the front binding.  I get 4 full turns of the Cap screw with BP cant discs. 

 

THE MOD: Moving the receiver forward places the boot +/- 1/2" forward of the original location - slightly forward of binding center.

 

[edit]: THE MOD: 55* angle w/ 6* lift.  20cm wide board (I normally ride 18cm or 19cm but I know guys like 20cm here).  The attempted symmetry of underhangs is better than before.

 

NOTES: With some modification the "Ice breaker" might be used with a flat head or other screw head type.  This might help with alignment and location of the receiver.  The reamer I used is shown.  (There must be a better way).  The different screw heads I found at my local specialty hardware store are illustrated here.  I picked the "Socket Cap" because it looked strong to me and I was hoping not to lose a leg. 

My guess is that this mod could help with M25, and I have heard reports that up to M28 could use some increased bias adjustment. 

Although this works with NO CANT the base plate can be rotated slightly (2-3*) achieving binding angles between the increments of 5* available on the center disc .  The receiver must be rotated to square with the toe block however which is a little weird. 

This is the first time I have had [roughly] centered boots since moving to UPZ years ago!

 

RIDING IMPRESSIONS (first day riding)

1) Everything seems solid, no movement or other concerns observed in the mod system.

2) With the mod my unloading from the lift was amazingly stable and perfectly tracking (a first).  No washout, or awkward stuff.  Totally relaxed comfort...phew  [edit]: This indicates to me I am now riding in a more relaxed neutral position relative to the board.  That could only help in every way right?!

3) With the newly achieved equal toe/heel bias I found my toe side turns looser than before.  I moved the front boot one TD notch back and this seemed to help.  Of course I could have been a product of bad technique but this is my impression...more testing needed.

4) My riding was generally improved and I will do some further tweaking (next the rear foot) now that I am not as constrained by equipment limitations! 

I hope this spurs other ideas!

Edited February 19, 2020 by rjnakata
2-19-20: Added photos of boots in board and TD cant disc application

[barryj]

Hey RJ,

  Bravo!  Seems feasible and functional.

Are you using standard size or  small TD Base plates?

Is the inclusion of a  BP cant disk only because it's the only way you found to connect/lock  the mod heel receiver down??  

Would like to see photos of modded and unmodded  bindings with your boot in it from different angles. 

Only thing I would have done different, which is insignificant is I would probably have used a 3/16th tungsten drill bit instead of a reamer.

You say your boots are "centered" now...but in the adjusted photo of your "centered" boots don't the black arrows point to the center mark on the boots??    .....So aren't you behind center.....heel biased??

 

 

[Lurch]

Great description + photos Rj. Thanks for sharing. A couple of before/after photos of binding mounted on board with the "fuego" would be really interesting. 

[rjnakata]

22 hours ago, barryj said:

Are you using standard size or  small TD Base plates? Is the inclusion of a  BP cant disk only because it's the only way you found to connect/lock  the mod heel receiver down??  

Standard TD cant discs can be used with this mod. Longer M8 screws could be used with the thicker TD cant disc.  I just happen to be riding a plate more lately hence the BP discs.  See added photos in first post.

[edit]: I am using standard size (not long) base plates.

 

22 hours ago, barryj said:

Would like to see photos of modded and unmodded  bindings with your boot in it from different angles. 

 

17 hours ago, Lurch said:

...A couple of before/after photos of binding mounted on board with the "fuego" would be really interesting. 

I'll add photos to the first post

 

22 hours ago, barryj said:

ur boots are "centered" now...but in the adjusted photo of your "centered" boots don't the black arrows point to the center mark on the boots??    .....So aren't you behind center.....heel biased??

The geometric center of the boot is 1/4" back of the "centering marks" you point to - at the sharpie cross I marked on my boot.  See this post, where @lonbordin states (Feb 8,) that info is from the UPZ rep.  The white line is the C/L of the base plate.  My boot is just forward of center (to the right in the pic).

Edited February 20, 2020 by rjnakata
added answer to one question

[Lurch]

So, after all this, some one school me the utility of  the underslung heel? 

Edited February 22, 2020 by Lurch
Re worded

[Mr.E]

Moving the bail ledge from the back of the boot (ala DIN ski boots) shortens the overall length for reduced angles. You see this sort of development with the Blax, UPS, Burton (etc) boots of the 90's. As Intec (and FAST) became a thing, boot ramp increased to accomodate the mechanical heel pieces.

[Lurch]

Reworded the question. If if the goal is to set the heel & toe over the edge, then if the boot is easily centered in the binding, it just becomes a simple function of angles, boot size and board width. Are larger sized UPZ as difficult to make heel & toe equidistant to edge?

[Mr.E]

I don't have experience with the Intec TD2 or 3, but I think it's as much a feature of running out of room on the bindings adjustment. I've had no issues centering 26 Upz on F2 Intec or TD2 bail bindings. 

I use the edges as reference rather than the center of the boot, just in case inserts are off center, etc. 

[lonbordin]

22 hours ago, Lurch said:

Are larger sized UPZ as difficult to make heel & toe equidistant to edge?

Yeah... To get close to boot shell center on 28.5 RC11 shells you need to adjust the rear sled of F2 titainiums and TD3sw  (both bail) to their maximum forward position. So if foot center isn't the same as shell center you won't be able to adjust forward to compensate.

[rjnakata]

For UPZ M26 (front boot only): I was not able to get my boot toes over the edges with both bail and step in with: ALL unmodded TD variants, F2's and SG's.  This was using the "Fuego" method with smaller radius 19 & 20 cm wide boards (not sure about 18 cm) or large radius boards.

I have tried to center UPZ M25 with similar results.  I hear that up to UPZ M28 need some added bias adjustment to gain "fuego" edge alignment.

The rear boot relates differently to the edge taper and I haven't found any difficulty aligning.

[lowrider]

Isn't boot centre sort of an arbitrary measurement with reference to ones anatomy and the true centre of gravity of your body ? To strive to achieve your own personal balance point by concentrating on the boot centre rather than body centre seems pointless. No matter where the centre of your boot is you will still end up with huge heel bias as far as balance is concerened. What is interesting is that our brain compensates and can allow one to balance our board edge to edge despite the fact we are all standing with the huge heel bias. 

I'm of the perhaps mistaken notion that boot out is the main point as well as a comfortable natural stance . Centering the boot across the board may be an exercise in measurement but that measurement is less relevant as you add degrees of rotation.

[Beckmann AG]

39 minutes ago, lowrider said:

Isn't boot centre sort of an arbitrary measurement with reference to ones anatomy and the true centre of gravity of your body ?

It is. And just as arbitrary as centering ones bindings on the insert pattern and assuming the job is complete.

Geometry is, however, a start and point of reference. 

“Where you come from is gone, where you thought you were going to never was there, and where you are is no good unless you can get away from it” 
― Flannery O' Connor, Wise Blood

( Also useful as a guiding principle toward how one moves over snow.)

 

45 minutes ago, lowrider said:

What is interesting is that our brain compensates and can allow one to balance our board edge to edge despite the fact we are all standing with the huge heel bias. 

It can, and will. However, it's better when the process of riding is the process of equilibrium, rather than the two being separate goals.

You can certainly operate your car with a partially deflated tire on one corner, if expediency demands, but you wouldn't do so on purpose. Why would you, should you do any differently on a snowboard?

[lowrider]

To be blunt. If the point is to prevent boot out micro adjust away. If it is to obsess about getting boot centre perfectly dead on for the sake of being dead on I'd direct my efforts in another direction. Nice thing about Skwal vs alpine carving board is it doesn't matter if the boot binding is centered.

[lonbordin]

1 hour ago, lowrider said:

If the point is to prevent boot out micro adjust away. If it is to obsess about getting boot centre perfectly dead on for the sake of being dead on I'd direct my efforts in another direction

Perhaps it's not about either of those points...

[rjnakata]

13 minutes ago, lonbordin said:

Perhaps it's not about either of those points...

I ride better.