Meidjo 3.0 release testing

[jasonq]

I have been messing a bit with 3.0, and finally got around to doing a rough release torque test using my handy torque wrench. One ratched inside the boot, with extentions leading up the cuff high enough to connect the torque wrench. Binding mounted on a 2x4 clamped to the work bench. By no means an official binding test rig, but was somewhat repeatable.

I tested:
3.0 toe only unlocked
Vertical ST toe only unlocked
3.0 toe + spring box
Vertical ST toe + spring box (i made a custom riser to marry the two)

spring box was on lowest release setting and springs on little preload. Basically the lowest release setting for the stock binding.

the results:
3.0 toe only: 52 Nm
ST toe only 31 Nm
3.0+spring box: 72 Nm
ST + spring box: 54 Nm

The spring box in the lowest preload and release setting addes about 22Nm.

ok but what about DIN? The release torque for a given DIN number is a function of the BSL. My BSL falls into the 291-310mm category. If your BLS is longer then the same torque would be a lower DIN setting.

that said, for my boot:
3.0 toe only: DIN 5.25
ST toe only DIN 3
3.0+spring box: DIN 8.75
ST + spring box: DIN 5.5

And according the the charts based on weight/height, i am a skier code J, type III, and over 50. type III bumps me two skier codes to L, but over 50 knocks me back to code K.

and code K with my BSL is DIN 5.25. I think in the distant past i used DIN 5.

So basically the 3.0 toe alone is my DIN setting and with the spring box is WAYYY too high for me.

looks like ST + meidjo spring box is my huckleberry*,**. And i may end up changing the release spring to a softer one to be able to be more into the middle of the adjustment range, and be able to set lower than 5.5.

Also, anybody notice that releasing chews the crap out of the toe of the boot? the tips of the pins leave gouges horizontally across the front of the toe. No real functional issue, but still it really chewed them up. in a real crash things might go fast enough and not so perfectly horizontal.

*Trab TR2 arrives monday, and that might change things.
**i tried to make a vipec toe work, but the stack height just ends up too high for me. and not confident with all that plastic.

[bobbytooslow]

And according the the charts based on weight/height, i am a skier code J, type III, and over 50. type III bumps me two skier codes to L, but over 50 knocks me back to code K.

and code K with my BSL is DIN 5.25. I think in the distant past i used DIN 5.

That stoner kid setting up people's bindings in the shop TOTALLY dials it in dead on spec, I'm sure.

[jasonq]

That stoner kid setting up people's bindings in the shop TOTALLY dials it in dead on spec, I'm sure.

I think you underestimate DIN spec marijuana. its like using Spice to navigate between stars, DIN marijuana lets a binding tech just know the right adjustment values to set. The DIN marijuana must flow.

and actually the DIN chart has a range for what release torques go with each DIN value. My 5.25 is nominal 50NM but it is a min-max of 45 to 55. And the 4.5 for one code lower is a range of 39 to 47. and one code higher is 6.25 and a range of 52 to 64. So if the binding was dead nuts nominal, i could set anywhere from ~6 to 4.5 and still be in spec for the torque range on 5.25. Seems to lack that legendary german precision.

[jtb]

Great info! It's so rare to see actual quantitative data about telemark, even if the precision is more gallic than teutonic.

I would be very interested to see the difference with the v2.x Meidjo toe. My own seat-of-the-pants data is that it pre-released too easily with the springbox tension anywhere below halfway. That makes me think the 2.x toe releases more easily, which I think you also suspected after seeing the spring tension on the 3.0 toes.

Speaking of the TR2, I got my shipment from Shapeways. I had to machine the metal part again, which was frustrating. I guess their tolerances just aren't very tight for steel. Anyway, it's all mounted up. There are a few special parts that I'll describe in more detail, but here it is:

[jnicol]

As usual, outstanding work jasonq!! Raising the bar yet again.

Now, the part I am most interested in is what you are proposing as your huckleberry.... merging a Meidjo spring box with an ST toe? And how? (i'm sure you already have done it, any pics?)

Now that you are set up, how hard would it be to test Lynx? You don't have one do you? how hard would it be for one here to loan you one for a test?

[xmatt]

jasonq, did you test a Meidjo 2.x for release to compare?

[jasonq]

quicky answers,
no lynx and no 2.x to compare. the only other toe i have is a superlight but won' work well with a meidjo springbox due to interference (unless i redesign the flex plate).

pics, right now my vertical + meidjo sits at having everything together, minus flex plates because i didn't want to knock the pins out of the 3.0 toes to get them. I have flex plates arriving monday from FHL. lack of flex plate just means step in doesn't really work, and may mean slightly less active, but shouldn't affect "heel down release". I'll post pics later today and then again when the flex plates arrive. Parts are carpet skiing quality due to the material used. final parts printed from nylon waiting until i figure everything out.

[SPQR]

jasonq - when you tested release value with Meidjo toe piece and spring box what setting was the duck butt set at? Level 1 which their V2.1 instruction manual claims is approx 3-4 Din, Level 2 approx 5-6 Din, Level 3 approx 8-9 Din or Level 4 approx 10-12 Din?

[jasonq]

SPQR,
it was set at 1, and low preload on the main springs. the 3.0 manual says the same thing. No idea about the 2.1, but clearly the 3.0 is somewhere in the range of 5 DIN settings higher than the manual for static release.

also, keep in mind i was testing the static release torque, or a slow fall. Given the meidjo doesn't have nearly the elastic travel of true alpine bindings, in dynamic loading i would expect to need to set the DIN higher than an alpine binding for the same dynamic retention (preventing "pre-release"). All that said, the actual DIN charts don't show a loading vs time curve, or at least no charts i have found (haven't looked in years).

so i guess what i am saying is the "effective equivelent DIN release torque" might be lower to account for some sort of blend average, blah, blah. And the static release torque for a given "effective equivelent DIN" might be higher than the static DIN value for a meidjo. Of course in that case you do have higher release torques for slow falls...always the danger of cranking DIN to prevent pre-release.

also note what i said about the tolerance range on the DIN charts up higher in this thread.

So relative to a true alpine binding, i am not doing apples to oranges measurements, more like granny smith to red delicious, for sure.

[jasonq]

[SPQR]

Thanks jasonq, not sure what to make of this. Meidjo V2 and V2.1 have released for me a few times and I’m glad they did. Too bad Meidjo doesn’t offer the older spring toes as well as the new ones, then you could choose between slightly more releasable or less releasable. This will be something to follow as the season progresses.

[jtb]

I agree with the statement about elasticity, again based on my anecdotal evidence. The two times Meidjo pre-released for me were quick hits, once on an ice patch and once hitting the other ski. I suspect it retains better when loaded up slowly. This is why I'm super excited to try the TR2. You can see the elasticity when you push your toe around, as it floats side to side before eventually releasing.

[SPQR]

I suppose in the big picture some people experienced a “prerelease” so Pierre felt obliged to tighten up the toe piece.

[Dostie]

I suppose in the big picture some people experienced a “prerelease” so Pierre felt obliged to tighten up the toe piece.

Maybe that was Pierre's motivation, but I think he simply had a light go off and he followed that inspiration to come up with, IMO, the freakin' best tech toe evah. So far. The Trab toe and Fritschi's Vipec toe are pretty rad too. Like Trab and Fritschi the M3 has a completely new camming interface to flip the pins from open to closed, and vice versa.


Nice analysis and test info Jason. Curious if you have an Ion toe to add to the test regime? If Dynafiddle was 31Nm and M3 was 51 I'm guesstimating Ion would be 45ish Nm.

[chamonix]

ST toe only 31 Nm

That's why I kept skiing out of my Dynafit Vertical ST binding, on hard snow..Glad to see the ST toe pieces have found a good home..
Nice work, by the way.