A Tibloc works differently than any other mini ascender as it doesn’t work via a moving toothed cam, and rather works more like a cleat. Although super effective, camming ascenders, by their very nature of biting onto a rope, will damage the rope if overloaded, even bite right through it (easy to do on a half rope if you really shock load it). Camming pulleys, being mechanical can also be affected by cold, ice and snow or dirt, stopping them from locking onto the rope. The Tibloc having no moving parts isn’t affected by any of these things, but the drawback is that a Tibloc requires a much greater level of skill and practice to use effectively and safety (they will trash your ropes if used badly, and also plainly not work). The other style of ascender that can be used is the Russian rope cam style ascender (as seen in old Troll/Yates Rocker and Camp Lift). This is the style of ascender recommended in Speed Climbing! By Hans Florine, but I suspect this is as much down to fear of litigation as effectiveness, as this style of ascender is way to heavy for alpine climbing, and I’d probably go for a Petzl Basic if it came down to a toss-up of heavyweight ascenders.
So what to choose? Well, the very nature of simul-climbing is highly dangerous (sometimes just taking off the rope and soloing together is safer), and so any technique that makes it less so has to be adopted. To make it work see my article, and by following the rules set down in the Petzl PDF you should achieve about a 90% increase in safety (as long as you follow the points in my article about the second not climbing faster than the leader, placing plenty of pros, and climbing well within your limit). But what to use? Well Tiblocs are light ad they’re the ascenders I carry on my harness, so for me, I’d used them. The one main point is that THEY MUST be used with the correct karabiner; a round bar oval or HMS. If you use them with anything else they can be unpredictable. Make sure the rope passes THROUGH the karabiner, and the rope diameter works smoothly with the Tibloc. Does that mean they’re better than ropeman etc? No, it just comes down to what you know and how you know how to use it.
The bottom line is protected simul-climbing It’s a great technique, but must be used with great care and an understanding of its limitations.
note image above is from El Cap report by Tom Evans.