Tuesday, November 2, 2021

RipCord: MicroTrax Thumb Loop Cam Release

The following step-by-step instructions are how to modify a Microtrax (MT) or NanoTrax (NT) with an easy release thumb loop when using as a back-up device to a Taz Lov or Trango Vergo primary device. This allows quick and easy descent after topping out or hanging on the rope; easily descend from a hanging top-out; quickly descend when doing laps for endurance; or to work a section/crux of a route. It allows you to open the MT/NT while holding the rope with the lower hand to help control the descent, while the other hand controls the lever on the primary device.




Since publishing on the FB TRS group, there have been three complaints made by arm-chair climbers and gearoom “test-pilots” who’ve never tried the RIPcord Release. I’ll address each of these here before getting into the mods. I want to be clear - none of these have been observed during my year and a half of use.
  1. “Cord will get entangled in toothed cam and prevent it from locking up.” This is pretty much impossible to happen since it is not a dangling single cord that can get flipped up into the cam. It is a short loop that’s on the back side of the cam away from the teeth.
  2. “Cord loop will get caught on something to prevent it from locking up.” Unless you’re climbing in a brushy/bushy area, there is nothing for it to get caught on. The loop is on the backside of the MT/NT facing the body between your legs and it is vertically oriented, not horizontal like a lasso.
  3. “Cam teeth will rub on rope while rapping causing it to snag and rip sheath fibers causing extra wear.” Take a look at the photos in my blogpost. There is plenty of clearance between the pulled open cam and the rope when rapping. If you use an older fatter rope, then it might be possible. I’ve used this mod with ropes that are 9.4-9.6. If it does snag the rope, then it’s going to lock up just like in a TRS “fall”. Once the teeth initiate the lock up, it’s the cam action that pinches the rope and stops movement, not the teeth.
  4. I've only done this mod on a Microtrax. I suspect that if done on a Nanotrax it would be best used on smaller diameter ropes (8.9 -9.4) because of the narrower clearances between the pulley and cam. If you try this on a Nano, please share your results.
If your “inner climber” is paranoid, by all means don’t use this mode. However, if it looks like something that might be useful to you, then give it a try and make your own observations. This mod is is for MT/NT backup use and is fairly easy and safe to test the loop before grinding off the lock-out tab. YMMV.

Now with that out of the way, on with the story. In the past I used an unmodified MT for a couple years and found that with certain ropes it would both inadvertently get locked open while climbing (dangerous) and, while in the open position get unlocked and bit down on the rope while descending (totally annoying). This could be part of the reason why Petzl eliminated the lock-out feature in the new Nano Trax. (Also, Petzl has put out a statement re the Mini Trax in relation to using it for TR Solo, though I've not found a similar statement re the Micro Trax, which they probably should have).*

The following is the solution I’ve come up with that has worked well for the last year+. If you choose to do this mod, make sure you know what you’re doing, both climbing wise and modification-wise. This is not something recommended by the manufacturer and is outside their design parameters. Do so at your own risk.

1)  Grind off lock out nub (Microtrax only). I used a Dremel tool with an 1/8” carbide ball bit. If you have a NanoT, you’re fortunate because, while there's still a nub there, there is no receptacle for it to fit in to hold it open. Therefore it's just an unnecessary appendage that can be ignored.



2)  Use a piece of 1.5 mm accessory cord that’s about ~12” long. It’s easier and better to have more cord to work with than too short. Insert cord through keeper hole in the plastic housing and then out the side. Tie an overhand knot, cut and burn end so it is close to the knot. Insert knot into the recess in the body. If you have a NT, there is a metal post and recess in the plastic body instead. Tie a scaffold knot around the post, trim and burn the end of the cord.



3)  Insert Sharpie (or something of similar size) to hold the cam open while working on it. Insert the other end of cord through the open slot on the backside of the toothed cam. Pull through and tie a Scaffold knot leaving it somewhat loose. 



4)  Adjust knot so the loop is the correct size for your hand/thumb. Getting the size just right is a critical and a tricky step because you don’t want to tighten the knot all the way which makes it hard to loosen and adjust. This step is trial and error and you probably want to have the rope and ‘biner on hand that you’ll be using it with so that it’s easier to judge the most efficient size of the thumb loop. The goal is to keep it as small as possible and to be able to open the cam all the way till it bumps into the plastic house (see last photo below). This is important so that it doesn't snag the rope. Once you’re happy with the size, cinch it down tight, trim the excess cord off and burn the end.

 



I’ve not found the RipCord to interfere with the action of the MT. In my setup it's not possible for the loop to get sucked into the toothed cam because it’s too small and there is no loose dangling end to get sucked in. I also haven’t found the loop catching on anything while climbing/"falling" because of its position on the back side of the device out of the way. YMMV.



On the Tope Rope Solo list on FB a couple of people did not like the idea of the cam teeth being close to the rope while rapping and the possibility of the teeth snagging the rope. This has never happened in over a year of use. Take a look at the above right photo which shows the thumb loop in use with the MT cover swung open. It's clear that the rope rotates around the pulley away from the toothed cam and at it's closest there is 5mm-6mm clearance. This is with a 9.5 rope. With a rope of 10mm or larger it could be a concern. With smaller diameter ropes it's not an issue. As with all things I post, if you are not comfortable with it, by all means don't do it. I'm simply sharing my experience.

The following video clip shows one of my TRS setups (with Trango Vergo primary device) with the MicroTrax as a backup and the ease with which one can easily descend at any point. This shows me climbing and rapping the first 25' of a 100' route.



BONUS: The RipCord loop can also be used as a very efficient tow loop if using the MT as your primary device. Use the loop to connect to your necklace or chest harness. When transitioning to descending, it’s easy to put a Grigri on the other free strand of rope and take it up tight, release the MT/NT and take it off the rope and just leave it hanging on your necklace/chest harness while rapping.
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* Petzl has studied the current usage of the MINI TRAXION as a self-belay device on a fixed rope. Serious accidents and many handling errors have been reported.

The risk of using the device with the cam held open is significant, as well as the possibility of accidental opening of the cam when climbing.

Consequently, the MINI TRAXION must be paired with a different ascender: ASCENSION, BASIC, MICROCENDER...
Petzl does not recommend using a system consisting of only two MINI TRAXION for self-belayed solo climbing with a fixed rope.”


https://www.petzl.com/INT/en/Sport/Appendix-4--Precautions-and-introduction-to-risk-analysis?ActivityName=rock-climbing