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Kyle Isenhart Super Rack
(#2519)

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

Technical Details

I acquired this rack from Ed Sira in at the 2019 NSS Convention. Ed acquired it directly from Kyle Isenhart around 1976.

My Kyle Isenhart Super Rack rack is 305 mm. tall, 62 mm. wide, 25 mm. thick, and weighs 779 g. The frame is made from 9.5 mm. stainless steel bent into a U, with an internal width of 39 mm. There are 4 brake bars. The bars are 25 mm. square and 69 mm. long. The spacer are 21 mm. tall. Allowing 35 mm. for the rope and 21 mm. for the spacers leaves 101 mm. for spreading the bars.

There are no markings on this rack.

Comments

Kyle designed this rack for long drops, and he published his design in The Nylon Highway #1. The large bars provide a larger mass for absorbing heat, and tend to run cooler that standard rack bars. He later published the results of temperature tests (The Nylon Highway #4) that showed the Super Rack ran about 30 to 35°C (60°F) cooler than a standard rack for moderate rappelling speeds.

Kyle emphasized the safety of the Super Rack in his article in The Nylon Highway #1, but his discussion focused on the strength of the rack, and not on its available friction. The Super Rack only has four bars (with spacers between the top two), and has less friction capability than a standard 6-bar rack. This generated some controversy in the caving press, with both sides having some valid points to make. When used by an experienced caver, the Super Rack does what it was designed to do, but it is not a beginner’s rack.

The rope grooves on this rack show evidence of some irregular machining, but there are no sharp edges or corners that could damage the rope.