I bought the Yak Nutz from Mountain Equipment Coop 4 years ago and was always nervous about torquing them too much and on one occasion the Yak nut "slipped" when I torqued them like the regular nuts. After revisiting the MEC website I realized that there were several thread options and decided to compare the diameter and threads using a thread gauge and die from my tap and die set. This confirmed the problem. I had originally bought the 10.5 mm x 1 mm Nutz but was able to exchange them for the 10.0 mm x 1 mm Nuts. These did the trick and the correct ones torque up like the normal nuts. I use a crescent wrench to tighten them. An open end wrench would likely work better as clearance is limited. One has to pull quite hard on an 8" crescent wrench. I don't bother with the torque wrench as a normal socket will not fit the Yak Nutz.
Yves, I forgot to add that the Yak tows very nicely. If you have paniers it is good to load them up first rather than having all the weight in the trailer. Front loading the trailer also helps. Its very stable when braking and having the motor regeneration brake effect is very helpful. When turning one just needs to remember the bike is that much longer!
Thank you! Your info is exactly what I needed. I will order the Bob Nutz from MEC (the 10.0 mm x 1 mm of course) I will let you know how I enjoy my Bob Yak again. It's been hanging in the garage for a year now...way too long.