2017-18 tech tele systems, tinkering, workarounds, and expletives

[dschane]

Dostie has been solidly synthesizing the tech info. (and then some):

http://www.telemarkskier.com/category/gear/bindings/

But I thought I'd start a new thread for the coming season and ask one question. Dostie reports the farther back you put the pivot, "the longer spring you need so it doesn’t compress too far too fast." I thought it was the other way around -- moving the pivot point rearward meant you would not bottom out as quickly (all else equal)? Which is it?

[bobbytooslow]

Dostie is correct. The further back you put the pivot, the more spring deflection (i.e. longer spring) you require.

Think of it this way (while remembering that we're compressing, or "deflecting" springs to get more length out of the cable unit):

- If the pivot were at the same location as the boot pins, lifting your heel would do nothing to the spring.

- If you placed the pivot way far back, like practically under the heel, even a slight lifting of the heel would require lots of deflection. Roughly one inch for every inch you raise the heel.

- In between are the positions we're used to. The G3 Targa has the pivot pretty far forward, and thus requires very short springs (inside a somewhat longer cartridge). The Vice pivot can be moved much further back, necessitating longer springs.

Does that all make sense?

To dork out further:
Technically it's not spring *length* that matters, but amount of deflection (i.e. the difference between its extended length and its fully compressed "bottomed-out" length). Generally a spring with the force we require and the dimensions we require isn't going to deflect much more than 50-60%. It would be great if someone could make a spring that deflected from 3.5" down to 0.5", and still was as stiff as we demand. Maybe the Defense Department could, with some exotic materials. Good luck developing that on a telemark equipment maker's R&D budget. So we're left to using what's commercially available from Lee Spring (and others) or Voile, 22 Designs, G3, and others. This is why Voile/OMG/Moonlight can't just take their Long Travel/Soft cartridge and "put a stiffer spring in it."

[Dostie]

dschane,

Think of it this way. The arc defined by the compressed boot is the same (for a given boot size). Where the elongated (springs compressed) cable arc intersects the boot arc is relative to the pivot point. The further forward the pivot, the further forward the intersection, which will therefore be higher up on the arc defined by the boot heel. This yields a higher angle (~40-50 deg.). The further back it is, the smaller the cable radius and therefore the lower on the arc the intersection is and thus, the smaller the angle is (~30-39 deg.) before the springs feel like they're limiting out.

[dschane]

Good information, gents, thanks.

[bobbytooslow]

So there's one part of all this I can't seem to wrap my head around: Manipulations to the arc lengths.

It seems there's an advantage to having what amounts to a transverse bar under the foot that a heel bail attaches to, and that serves as the effective end of the boot sole (minus 6mm for bellows flex) and the point you measure to (then add spring deflection to) to get the radius for your cable arc. BD's O1 & O2 had this, 22D's 75mm bindings have it, G3's Enzo does, even jasonq's POLR binding is configured this way. The logic being that you're shortening the lengths of the static parts of the cable while the spring deflection remains the same, thus making the spring deflection value a higher percentage of the overall cable length. Everything rearward from the transverse bar is fixed together as one static unit, so perhaps its length doesn't matter? Maybe the true measuring point isn't even the transverse bar, but the end of the spring nearest the toe (for beyond it everything is pretty much static)?

I think I've confused myself just in typing this. Does anyone have coherent thoughts about the effect of manipulating the arc lengths from the simple OMG-TTS-style cable configuration? And about what the true point we should be measuring to?

[Dostie]

bobbytooslow,

Not following you. Can you draw your Q to clarify? And perhaps my drawing is not clear.

[jasonq]

bobbytooslow,
i understand what you are saying and you are partially right. in the case of what you call a bar under foot, if what you mean is like the the heel bail assy on a BD 01 or 02, then yes, it does in fact more the cable/boot effective attachment forward to that bar. But it also lowers the attachment to the level as well which decreases initial activity due to a flatter initial angle (and increases activity at the other end due to applying the load farther from the axis). Moving the attach down is a far greater effect than moving forward. For the case of the version of the POLR shown in the article (or the axl/vice), not as much. it is more like having a joint in the middle of the cable.

But this does bring up something that is rarely discussed directly, the key difference between an under foot routing and a side routing is an underfoot routing is always a longer path. you will always need more spring deflection. The reason is that as the heel travels in an arc and the boot bends at the bellows, under foot routing has to follow the bottom of the boot, but a side routed cable can take a short cut on the sides. That is one reason underfoot in general seems more active with quicker initial engagement. Think about about a side routed cable on a classic 75mm binding like a riva or switchback, heel on the heel pad, and where all the initial heel lift was bellows compression. the side route cable can actually get shorter in that case if the pivot is far enough forward and high enough on the two wings.

Just keep in mind the intersection circles is really a useful thought experiment for determining trends and magnitudes, but doesn't take everything into account.

[Charley White]

Placing here as most title relevant of many TTS threads. Made some tech heel plugins a la Jasonq, but molded using my go-to material, epoxy. The heel throw snap is great, but I see problems for them. On an AT rig tour at Lassen last June, I had problems with mud & pebbles clogging the heels & pincups, requiring more fine-work than I wanted when wind sprang up at icy summit. These TTS adapters are too big and heavy at moment, so will shave. [Edit: have done, and pictures now of sleeker improvements] But I already see necessary futzing when: walking on pavement, on crusty snow, on packing snow. They pop in and out easily, so figure to add that to my tour regime. [Edit: they are not glued in place. Will only come out when & if I sell them]

[jnicol]

What's the purpose of these, Charley? keeping junk out of the tech holes?

[Charley White]

Keep the heel throws on. Mine don't secure well on the ledge. Secondary is to raise effective (relative) height of pins.

[jnicol]

Ok, makes sense.

[teledorth]

So I think this is the year I'll take the tts plunge.

I am thinking I'll go with the cheap speed turn or radical toes, flat mounted to the ski probably, and then a b&d or diy cable anchor, regular voile springs - or maybe the adjustable kreuzspite ones. Unsure about heel height atm... Does this sound reasonable? I am defintely interested in lower activity

And secondly, what's the verdict on using a stock vice/axl spring and cable assembly? I know JQ used some 22d parts but his setup has a lot of other special parts. I'm more curious about using them without modification.

[dschane]

I’d go with Radical toes and try that B&D part. Skimo can sell you the toes alone and the Kreuze cartridges (go soft). It will feel quite neutral. I like the Kreuz heels — simple, low, and light.

The problem with the standard Voile cables is you’ll like bottom them out. The Voile long, soft cables may be cheaper if you can find them in the U.S. But having the option to get stiffer springs with Kreuz’s system is brilliant.

[jnicol]

Just to add some info…. there are always numerous ways to set up a tele tech, even with Dostie’s wonderful and informative Tele Tech Chronicles giving a nice foundation.

You ‘might’ get away with the regular voile springs if a) your boot isn’t too big and b) you mount it forward for, as you say, low activity. If you have some in your parts bin it’s worth a try. Otherwise, if you are buying cartridges I’d suggest going directly to Kreusptize to reduce the risk of wasting money.

Heel height plays a large part in the ‘feel’ of the binding and stance on the ski. If you are going flat on ski at the toe, then a shorter heel 20mm or shorter should work well. You may have to modify something. The beauty here is it is pretty simple to fake a heel with any old thing until you determine your preferred height and then find the closest one, modifying if needed. The heel height also impacts the space between the bellow and whatever you are using for support there. May also end up needing mods.

[Allan Fici]

teledorth, Here’s a TTS (forefront) with a 6mm shim underfoot the crab toe, custom 12mm mounting block and 17mm Kreuz heel. This yeilds a pretty neutral stance ramp and close to the deck. You could go with a 3mm shim at the toe and have 3-4mm ramp heel to toe. Kreuz heels are 17mm, OMG/TTS are 21mm, G3 are 25ishmm, 22 designs are 30ishmm in height. I skied the Speed Turn for 5 years on my early TTS bindings, I’d hunt around online to see what deals you can find on crab toes. The B&D block will allow you to use the Voile rods which are easy to custom bend. Or make your own blocks.