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Lambone
Ice climber
Ashland, Or
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Nov 10, 2009 - 09:33pm PT
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The Kong Block Roll enabled me to 1:1 haul from the ground with no partner counterweight for the first time in 14 El Cap routes. Dig it...
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Ihateplastic
Trad climber
Lake Oswego, Oregon
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Topic Author's Reply - Nov 27, 2009 - 12:52pm PT
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Werner... Here's what Deuce had to say with respect to your pulley...
Not sure which pully I gave Werner. I worked on about a dozen designs with Rock Exotica, the current Wall Hauler is largely my concept, though Rock was very clever in the implementation. I think I gave Werner one of the prototypes. There were lots of different prototypes.
Here is a vague and highly shrouded hint... expect some good news on the wall gear front in the next six months!
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mongrel
Trad climber
Truckee, CA
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Regarding Mark Hudon's comment, it is true that the diameter of the wheel/sheave/pulley makes no difference, 1:1 is still 1:1 (also makes no difference in 2:1 or 3:1 setups either), but there is a practical correlate of diameter that does make a difference: bearing friction. For example, the Petzl site includes a pulley comparison table with a column for "efficiency" which I presume means how much work energy is lost through the pulley. This number varies from 71 percent up to 95 percent. I'd be willing to bet that no small-diameter pulley has a high (90+) "efficiency" and few or no large-diameter ones have low efficiency, just due to the type of bearing that the manufacturers choose to use with their various pulleys. There's certainly a weight issue too, ball bearings weigh more than so-called self lubricating (or no bearing at all, just the wheel and shaft). Thus, I imagine that Lambone's very telling empirical comment about hauling with the KBR probably relates to the bearing quality more than any other single characteristic of the device, and it sounds like this more than compensates for its weight.
For sure, rock friction is WAY more of a factor than bearing friction, wherever the climb is less than vertical, but it doesn't help to lose another 10-30 percent of your effort.
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