7tm binding repairs

This post is about 7tm bindings and the DIY repairs I have made.

My beloved 7tm Power Tour XR Telemark bindings have been so wonderful to ski on for so long that I have worn out some critical components. I thought that the repairs might interest some other Telemarkers who have used and loved their 7tm’s as much as I have. I should say I also have the simple red model 7tm’s and I also make some comparisons between the two similar bindings.

As a newbie, initially, I had the simpler bindings on my first set of Telemark skis. I started to learn real Telemark turns with other keen Telemarkers. I confess that I purchased the second set with the step-in function so that I could keep up with the crowd. At the same time, the power bar option came with the newest binding. Without much thought, I fitted them and as the saying goes, “the rest is history”. They made the turning so nice that I have never considered removing them. However, when forced to go back to use the bindings without power bars, I really miss them.

I provide a context to my need for the repairs. I would not describe my skiing as particularly aggressive or hard, just persistent. At ~75 Kg and mature age (about 20years older than 50year old knitted ski suit onesie in the video below. “You do the calculation!”

I keep my toe release setting so low that it is almost off the scale on the window. I like it that way and never begrudge an occasional release and have all my bits still connected in the original place without any pins or prosthetics.

I have mainly used Scarpa T1 boots. I like lots of tight linked turns and I keep my skis rather too close to each other. This fault is clearly the contributing factor for failure that is the subject of the first repair (also displayed in the video below). “I am not blaming you Mr. 7tm.”

Here is a video of me skiing in my beloved onesie that was knitted by my Mum.

I have consistently used the 7tm power bars (love them). I like how they make the bellows more active during turns and possibly contribute to the second failure/repair that I report on.

Even though I have two pairs of bindings I mainly use the ones with the power bars on multiple sets of skis by fitting extra binding plates to those skis. Those skis are fat and on the heavy side and have been just about worn out by a lot of use with the bindings being switched between both pairs (or maybe 3 pairs) of skis.

7tm binding repairs

Worn out nuts

The alpine tour binding has a pivot pin at the front of the binding that allows the boot and binding to swing freely when required by rotating an actuator leaver under the binding plate. The rubbing of the inside nuts on these pivot pins against the opposing binding and ski edges during my skiing caused the original nuts (and the threads below) to wear away.

I fixed the problem by replacing the original pins with quality stainless steel bolts (with Allan key heads) and nuts from (BJ Bearings type store). I used an angle grinder to grind a suitable flat on the thread end of the bolt so that it could fit through the round hole with a flat side in the binding. I used nylon packed locking nuts on the other threaded end of the bolts (outside of binding). I haven’t currently got a photo of the originals bolt and nut, but here is a photo of the replacement bolts heads and they are slowly suffering a similar demise.

[Add a photo of the original worn bolt]

The replacement bolts and nuts worked perfectly, but after much use (or continued abuse) they are also wearing out but will be cheap and easy to replace. “Alas, according to our beloved Norwegian Telemark Master the quality of my Telemark stance has not improved.”

Alpine tour release button

The alpine tour binding of the 7tm binding has a strong rotary button device with a mushroom head that holds the binding down for Telemark turns. The button head has a flat side cutaway on it. When this missing flat section is rotated toward the keeper plate, the binding is allowed to hinge forward without any resistance for alpine touring.

In my case, a portion of the button broke off and the binding was free to hinge forward all the time. “Luckily this breakage happened towards the end of the last day of a three-week ski trip to Japan just as a virus that the world would later call bloody Covid 19 was spreading out of China and making us have a hasty retreat homewards.”

I replace my bindings with my old red 7tm s and skied for a few more hours. This switchover made me realize how good the power bar effect was and how much I missed this feature when it was absent.

The fix for the problem was to remove the button and weld some metal back on to replace the missing portion of the button. Then I carefully ground the metal to make the button the same shape as the original. Removal of the button was very difficult. It took me considerable time in a well-equipped workshop to remove the hardened pin that locks the actuator arm to the button. I even needed to grind a customised drift punch to complete the removal of the fine pin.

A more serviceable button

When considering the reassembly of the binding, I thought that an alternative holding pin such as a split pin (of the same diameter as the original pin) would make a simple substitute. It would be ugly (but unseen). However, it would be easy to remove with a simple multitool any time in the future.

A more field serviceable button

While repairing the button I realized that there was plenty of button head available. The only problem was that the clever actuator arm would not allow the button to rotate to allow its use in an emergency.

With a field removable split pin, another unused part of the broken button can be rotated into position to effectively lock the binding down. A 4mm dia bullet head nail can be used as a simple keeper for the button and the nail head gets caught in a groove in the binding so that it can not fall out. It could be easily positioned or removed with a backpacking multi-tool (or strong hands) such as used for the removal of the split pin. This would allow me to keep skiing or get back to base (or complete a skiing holiday) with the full telemark function but without an easily switchable tour mode.

I have modified the other binding to work with a split-pin so that it is ready for field repair. This is just in case it should fail (before I do). It has earned just as many turns as the other binding or my other leg.

Maybe someone will come up with a way of turning the nail into an actuator that can switch between tour and Telemark modes while on the skis?

Ski slutting

I have already mentioned how the 7tm bindings allow me to swap the binding over my quiver of skis. If you ski with other people who have 7tm bindings, as I often do then there is another fun aspect of the binding. We are able to rapidly swap over skis and try out other skis while retaining our own release settings. It provides an excellent opportunity to try before you buy or trade skis.

Tim

There is an interesting, 7tm binding forum topic on ski.com.

You may also be interested in my DIY glide wax and pocket applicator or Glide compounds that can hide in your toiletries.

If you are really backcountry ski-crackers like me, you may be interested in my DIY breathing polyester pyramid tent to keep you drier at night, a tiny 400g wood stick fired backpacking tent stove to keep you warm and cook your dinner, improved DIY telescopic roll up stove pipes and a DIY stove jack to make it all light and safe.