Moderator: Tim White
Cody JW wrote:I own a mini rack with hyper bar and have found that if you are going over a tricky lip and the rope is dirty or stiff it is easy for the rope to jump over the hyper bar. For me at 220 lbs. when that happens I will not have enough friction and had to have a bottom belay the first time it happened.
I agree with you on the bar movement thing. Most standard rack set ups do not allow ample movement of the lower bar to give much friction adjustment. Five bars on a regular 6 bar rack usually will. If you use all 6 bars you better get an 18" frame or longer. My mini rack gives me no room to move the lower bar with caving rope.gdstorrick wrote:LukeM wrote:The only reason that I ask is that a shorter rack will provide more friction. For their micro rack BMC offers two different lengths, and the shorter provides a good deal more friction.
More precisely, AOTBE (&TNA), a longer rack can provide less friction. Rack length below the bars doesn't change friction, and one can push the bars together on a long rack. If you need more friction, changing to a shorter rack won't help (unless it is so short that there isn't room for the rope ).
If you check the tabulations on my web site, one of the important ones is the "usable" length for bar movement. Good rack users control their descents with bar motion. If someone has enough bars and a long enough rack, and they are either braking or feeding with their braking hand on free drops, they aren't controlling the bars as well as they could.
I find it amusing that my 1994 BMS Mini Rack is shorter than my 2009 BMS Micro Rack.
gdstorrick wrote:More precisely, AOTBE (&TNA), a longer rack can provide less friction. Rack length below the bars doesn't change friction, and one can push the bars together on a long rack. If you need more friction, changing to a shorter rack won't help (unless it is so short that there isn't room for the rope ).
LukeM wrote:longer version is especially helpful for lighter people and the shorter version is nice to save space/weight as long as you are heavy enough to rappel effectively without needing more bar spacing.
ON_ROPE wrote: Obviously, you can see I have an opinion on the matter. Open frame rappel racks are the best device to safely rappel long drops. The rest are lucky.
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