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Petzl Tibloc B01
(#131, 132, 2073)

Front View Rear View Side View
Front View Rear View Side View

Technical Details

I acquired two Petzl Tibloc B01 ascenders in 1999, one from from On Rope 1 and the other from Inner Mountain Outfitters. I acquired three more in 2017 as part of Bob Thrun's collection.

The Petzl Tibloc B01 is 52 mm. tall, 36 mm. wide, 18 mm. thick, and weighs 39 g.

The design uses a U-shaped plated steel shell with a diagonal slot. A carabiner fits into the slot, and when the climber's weight is applied, the carabiner slides downward with respect to the shell, wedging the rope and providing enough friction to support the climber's weight. The inside of the Tibloc has numerous down-sloping conical teeth in a (^7 pattern to ensure that the shell does not slide downward when weight is applied.

One side of the Tibloc is impressed with Petzl logo, "TIBLOC," "ROPE," a circle-with-a-dot icon, and "8≤Ø≤11." The other side is impressed with an icon with "1" through "12" arranged in a circle, an arrow inside pointing to the "4," and "99" straddling the arrow; the Sieg Heil icon, and "UIAA CE0197 EN567."


The Petzl Tibloc is very similar to an old ascender design patented by Kent Kammerrer in 1985 (US Patent 4,667,772).

The instructions that come with the Tibloc state that the carabiner must have a round cross section with a diameter between 10 and 12 mm. inclusive; however, Bruce Smith of On Rope 1 has demonstrated (but does not recommend) a ropewalker system using 3.5 mm trapezoidal rapide links.

It is essential that the Tibloc be set firmly so that most of the teeth are engaged, since if only a few are set, the Tibloc will slide down the rope, tearing the sheath in the process. Petzl emphasizes this in their instructions, and recommends the techniques shown in the figure to the left. Misuse will damage the rope - note the shredded rope in the figure to the right. Bruce found that filing the top three teeth off helps reduce the likelihood of this occurring, but of course this voids any warrantee. I find the risk of rope damage to be so severe that I avoid using my Tibloc except for demonstration purposes. I'm not the only one - the Tibloc is banned from the NSS Convention vertical contests for the same reason.

The Tibloc has attracted a lot of attention in caving circles, probably because most cavers are looking for a lighter climbing system. I'm not as impressed as they are - Salewa introduced a much smaller and lighter (albeit semi-mechanical) ascender decades ago. The Tibloc might be a be a nice lightweight device for emergency use, but an RBS knot doesn't require the Tibloc. Prusik knots are lighter still and don't require the carabiner.