Dynafit on Spruce Riser

[jjue]

Latest garage mod: Dynafit binding mounted on Spruce Riser with studs for ski crampons. More details to come. Bottom line save your old Spruce risers! They will come in handy if you want a touring binding on your skiboards!


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[jjue]

I have been very happy this season with my custom modification of the Receptor binding with a Dynafit tech toe and have been wondering about how to get a tech binding on my Spruce longboards. I asked Jeff Singer if he ever thought of selling a blank riser so folks could mount whatever binding they wanted but he said that liability insurance concerns prevent him from doing so and he will only sell risers that he mounts himself with bindings. He did say that users have removed mounted bindings from their risers and mounted bindings on their own at their own risk . I have done that myself with the Tyrolia Attack AT 14 binding ( an Alpine binding that fits AT boots as well as regular downhill boots) that I put on one of my risers but that was easy because the binding hole pattern exactly fit the multiple hole patterns pre drilled in the riser. If I was going to put a Tech touring binding on my unused riser I would have to do the work myself .

How the Spruce riser works is that multiple 3/16 inch diameter mounting holes are drilled along either side of the front toe area and back heel area of the riser .
Here is a picture of the holes in the back of the riser that are not covered by the binding.
IMG_20210409_085955881 by Jack Jue Jr, on Flickr
These holes can then be used with standard alpine binding screws to mount Tyrolia/Head bindings . The mounting holes are 40mm apart . The holes are somewhat smaller then a regular alpine binding screw and when you hand screw the screw into the hole the screw self taps itself as it is screwed in . You should use a hand and not a machine screw driver and use hand pressure or otherwise you may strip the hole . It is important to go past the point of initial resistance as you are screwing the screw in as that is the resistance as the screw is getting into the hole and self tapping itself . You just go past that point until the scew firmly seats itself.
I was interested in drilling new 3/16 inch diameter mounting holes to mount an old Dynafit binding I had. After removing the previous standard Tyrolia binding from the riser, I laid my binding on the riser and checked to see if the mounting holes would miss the predrilled mounting holes on the binding . Luckily they did being a narrower 30mm width pattern at the toe and a 32 mm width pattern at the heel .
I put my boot in the toe and heel of the binding and laid it on the riser and marked binding holes on the riser. I then used a center punch to create a dimple at each hole and then used a 3;/16 drill bit with a heavy duty hand held home power drill unit ( I had to buy a new drill because my wimpy home drill was ok for wood and plastic but found metal a challenge !). With the more powerful drill, drilling through the riser is very easy and quick .The toe and heel pieces of the binding are then attached to the riser with their own manufacture supplied binding screws.

Unused holes in the riser that are meant to attach to a 4x4 board are used for crampon studs. I just invert a 1 1/2 inch 1/4 inch phillips head screw and then tighten the riser down to the board . The screw which serves as a crampon stud stays nicely in place and a standard 120 mm Voile Crampon can be attached to the board if needed using wingnuts and fender washers .
You can see from the pictures that there is still good crampon depth even though the Crampon is mounted over the riser.

IMG_20210409_085930371 by Jack Jue Jr, on Flickr

IMG_20210409_085945142 by Jack Jue Jr, on Flickr

The number of touring bindings that have a binding pattern narrow enough to avoid the predrilled riser holes is limited and generally are the simple paired down basic tech bindings.
Here is a nice link that gives the hole mount widths for toe and heel which are critical if you want to mount a touring binding on predrilled Spruce riser.
Bindings with a toe /heel widith of 32 or less should work ,
https://skimo.co/tech-binding-hole-patterns

The end result is a really lightweight touring set up . Weight of board and binding is 4 lbs 7 oz per board (Slingshot), compared to 6 lbs for my Slingshot mounted with my Fritschi binding on a custom riser , or 6lbs for my riser mounted with my downhill Tyrolia attack binding. Stack height of the boot above the board with this set up is exactly the same as with my boot in my Tyrolia downhill binding on my Spruce riser. No added height above the board which is very nice.

I am eager to try the binding with my Spuce Slingshots in the backcountry! Let me know if you have any questions.

Disclaimer:
Understand that backcountry skiboarding is a high risk activity and I recommend you take avalanche courses , purchase additional avalanche gear such as beacons , shovels and probes and go with experienced backcountry riders. Also this a personal modification that you choose to use on your skiboards accepting all risks inherent with equipment failure and backcountry risks . This is not a manufacture recommended use of your binding or these binding parts and is only a binding modification I have done myself for my own use and am sharing with the skiboard public for their own education as to possible personal ways of modifying their bindings for backcountry use.

[Roussel]

Awesome! I wish we could get blank risers to mount whatever we want on.

[jjue]

I wasn't completely correct about the Spruce riser holes and wanted to post a picture and discuss the challenges of avoiding the pre drilled holes . The many front riser roles are maybe 38 mm apart , the three rear riser holes are 40mm apart and the middle riser holes are 18mm apart . The picture shows my dynafit binding mount adjacent to a bare riser. Front mounting holes for my binding are 30mm apart and fit inside the front riser holes of the Spruce riser , my rear binding holes are 32 mm and 36mm apart. I have a size 11 ski boot , boot length 326mm. Basically depending on your boot size ( not much longer then mine you will have plenty of open space to mount your heel piece as you can see from the photo. up to about 40mm in width between holes .The critical piece is having front binding holes of 30mm or less . Even with my binding holes 30mm apart I needed to make sure that I made the holes between the front riser holes to avoid the width of the hole getting into one of the riser holes. In looking over bindings that would work . All Dynafit bindings should work except the newer versions with the rotational toe such as Dynafit radical 2.0 and Dynafit Rotation series. To be sure , I would bring a unmounted riser to a ski shop that has the binding you are interested in and a jig and make sure the mounting holes would avoid the riser holes. I am not sure that ski shops would do the mount for you as this is a non traditional mount .

IMG_20210410_104826354 by Jack Jue Jr, on Flickr

[jjue]

Just got back yesterday from testing this rig in the backcountry. Trip report here. I found this set up a real winner. It is now the lightest of my backcountry rigs weighing in at 4lbs 7oz for the board and binding. It was a real joy on the climb up and way better then climbing with my Fritschi touring rigs . I did find a slight loosening of my screws that connect the riser to the board which I have not noticed using riser on my downhill bindings. I think this may be from the unusual twisting climbing motion on the front of the bnding that climbing with a touring binding on a spruce riser causes.
I may add some loctite to the screws to try to prevent this but otherwise it is a good idea to carry a phillps screw driver in your pack to periodically check the riser screws.

DSCN0040 by Jack Jue Jr, on Flickr

There is very nice control on the downhill and in backcountry snow .I notice no difference from my standard downhill rig.

So some my ask would I just substitute this for my standard downhill binding on the Spruce boards ?
Here is a comparison side by side of my new Dynafit mounted Spruce riser and my Tyroia Attack At !4 binding (ps this is not a standard offering by Spruce but it possibly could be special ordered by Spruce if a customer wanted as it fits the standard tyrolia mounting pattern predrilled on the riser)
The advantage of these two bindings is that I can use the same Dynafit Radical Alpine toouring boot in both bindings.
IMG_20210412_141534571 by Jack Jue Jr, on Flickr

I think the answer to my own question is that I will reserve the Dynafit set up for the backcountry and use my regular downhill binding for the resort. The downhill binding I think offers safer release characterstics in chopped up , cruddy , and moguled resort snow, more binding elasticity in hard snow and will be more durable being banged around in firm resort type snow. , as well as being a much tighter boot to binding connection at the heel then the two pin heel set up the Dynafits have. I think performance on hard snow and hard carving should be better.

Interestingly , the other binding modification I have done this year , the dynafit toe on a receptor riser is I think completely suited to both resort and backcountry use and can be used as my all around all purpose binding . The reason is that it exactly duplicates all the characteristics of a standard receptor non release binding with a rigidly fixed toe and heel atop a metal riser on a nice elastic cushioned base while offering equal climbing prowness to a standard Dynafit binding because of the nice dynafit toe. It is heavier then the Spruce riser with Dynafit binding weighing in at 4lbs 14 oz for a Spliff mounted with a tech toe and bale with telemark lever but I will prefer it on my 110 and below boards . It eliminates the need for the dynafit heel unit altogether.and provides a totally clamped down rigid heel connection with a lever and the rigid locked out pin at the Dynafit toe. ps I have found that I needed to add loctite to the two screws that connect the front plastic hdpe plastic front piece to the receptor riser to prevent loosening again because of the twisting nature of climbing on the front toe in backcountry touring . I have found no issues with any loosening of the screws connecting the receptor riser to the board.
Here is a picture of my Receptor non release Dynafit toe binding in downhill mode.
IMG_20210317_121424024 by Jack Jue Jr, on Flickr

Here is a picture of the same boot locked in the full Dynafit binding on the Spruce riser.
IMG_20210412_150439860 by Jack Jue Jr, on Flickr

For reference a standard Receptor binding on a Spliff is 4lbs 3 oz.including the leash.
My Tyrolia Attack binding on a Spruce Riser on a Slingshot is 6lbs.

[Steeps]

Awesome! I wish we could get blank risers to mount whatever we want on.

Bert was looking into some options in the Kootenays for custom-machined risers, and had talked to Carl Labonville about it, too. I should follow up with Carl, he's local and a legend:

https://exegi.ca/about/
https://www.powder.com/gear-locker/g...egends-skiing/
(note that 2 of the 4 are Goldenites... I'm in the Blaeberry and worked with Jair's wife on my first job here; Nicholson is just south of town)

A bit house poor at the moment, but should be able to scramble enough together for some touring kit by next winter. I bought shovel, beacon, probe last summer, but it hasn't even come out of the box yet.

[jjue]

Nice day testing the basic Dynafit binding on the Spruce riser at the resort on my Slingshots.. Tested the binding on groomers , on moguls , on steep broken up crud , and some icy snow.
I was very pleased . The binding did not pre release , Other then a bit harsher ride then my Tyrolia Attack binding on the riser the binding felt very similiar , Excellent control and a tight no slop feeling connection. I did hit some buried rock under powder and came out of my binding in a fall as I should have. I have the bindings set to a release setting of 7 for vertical and lateral release at the heel.
I do think that since the binding is mounted on a non flexing aluminum riser rather then directly to the skiboard there should be less pre releasing . I feel confident now riding this binding at the resort if I have any thought of doing some out of bounds or side country laps , otherwise will stay with my downhill Tyrolia binidng. The lightweight of the Spruce riser/Dynafit set up is great and is just 4 oz more then a standard Receptor binding per board!

Here is an old link with a lot of discussion about using Dynafits for resort skiing
https://www.tetongravity.com/forums/...ng-on-dynafits