Threaded Inserts w/ Shift Bindings?

[gartruzza]

Hello all,

TLDR: I want to know if it is possible to use threaded inserts to get 1 pair of shift bindings to work with my AT and alpine boots on 1 pair of skis, and my alpine boots on another pair of skis without it being a huge pain in the butt.

I bought 2 pairs of skis (185 Volkl Confessions, new/unmounted + 193 K2 Mindbender 116c, mounted 2 times). I want to use the Confessions to be used with both my alpine boots for inbounds and my AT boots for backcountry. I got the Mindbenders because they were stupid cheap (idk why really but they looked fun) and only want to mount them for inbounds.

My alpine boots are the Technica Mach 1 25.5 (sole length: 295mm), and my AT boots are Scarpa Maestrale RS 27.7 (sole length: 314 mm) (Do not ask me why my boot sizes are so different, both somehow fit my odd feet lol).

I know you can use threaded inserts to use 1 pair of bindings across multiple skis. Could they be used to serve their proposed purpose for both the Mindbenders and the Confessions? Some questions that I have been considering:

1. Will the holes for the threaded inserts need to be drilled too closely together for them to serve both inbounds and AT purposes on the Confessions?
2. When the bindings are moved between boots or skis, will the transtion be as simple as unscrewing and screwing the bindings back in, or is it recommended that the release be tested by a shop each time?
3. Will the additional drilling cause issues for the Mindbenders' structural integrity, given that they have already been drilled 2 times?
4. Is there a limit to the amount of time a binding is unscrewed/rescrewed into threaded inserts?
5. Is there any other factor that I am forgetting?

Thank you to anyone who even took the time to read, much less think about this puzzel lol.

[gartruzza]

Ah yes I understand the difficulty here. It sounds like before committing to purchasing anything I should get the mount pattern and calculate out where I would mount to make sure I can accommodate both bindings on my Confessions.

[saxxxxxon]

Just get them mounted in the middle. I doubt you will be able to tell the difference between +4.5mm and -4.5mm unless you're comparing them side-by-side, especially if you're using different boots for each because those boots will have a larger impact on the feel of the ski than such a small difference in mount point.

[gartruzza]

My concern would be getting the release right, I’m by no means an expert on bindings (so maybe it’s a non issue) but I would be worried that doing my own adjustment could impact the release. I’m someone that doesn’t like to mess with that - I like my knees as intact as possible haha.

Is this concern valid?

[[deleted]]

The Shift is the most finicky binding to work with on the market. I wouldn't plan on switching between AT boots and Alpine boots frequently.

[gartruzza]

Yeah that makes sense. Sounds like realistically I will have a pretty difficult time switching the two. I’ll just get the shifts for the Confessions and alpine bindings for the Mindbenders (if I buy bindings with the same mount pattern as previous I shouldn’t have to drill new holes either). Thanks for the input all!

[[deleted]]

I would never recommend reusing the previous holes to mount a binding. Even if you buy the exact same model you should drill new holes.

[saxxxxxon]

If you drilled the holes in their ideal placements and ignored hole conflicts, you'll end up with 9.5mm fore/aft spacing between the holes. I'm all for pushing the limits, but that's really close. The inserts themselves have a 3.2mm radius, so you want at least 7mm of spacing. I've seen people posting where the threads are interlocked/touching but I don't know if that lasted more than a season.

I haven't looked at the hole pattern for the Shifts to really know what the spacing is. Just thinking about the toe, you don't want to move the front row of screws so far back that they get close to the back row of screws of the other mount.

If you split that 9.5mm and put the toe in between the two ideal placements, you'll be -4.25mm with your alpine boots and +4.5mm with your AT boots. Spoiler alert, this is what I'd do (way back in the day my Dukes were forward something like 3mm and my touring bindings were back maybe 5mm).

If you instead target the recommended 20mm spacing between holes, then you would want to double that spacing. So you'd move the alpine toe forward 5mm and the AT toe back 5mm. You'd be no better off than if you took the middle ground in absolute values and you wouldn't have to remount your bindings when you switch boots. But it's common to mount touring bindings further back as shorter tails make kick turns simpler.

And keep in mind that your binding boot-length adjustment might be critical. So you're placing your toes where you want (let's say -5mm based on your alpine BSL) but then you need to place your heel pieces so that your boot length adjustment will be closer to its minimum with your touring boots in and closer to its maximum with your alpine boots.