moss
Been here much more than a while
- Location
- Carlisle, Massachusetts, U.S.
Just retired my second "home-made cordage" TM bridge after 15 months hard use. I used another of the same construction for the previous year+. I'm back to the Teufleberger stock TM bridge for this round, great stuff, happy to be climbing on it.
The cordage is built with a braided Dyneema SK78 core (stripped from Samson WarpSpeed II 9.5mm sailing line) fit into a cover from a core stripped Sterling HTP 10mm line. I added a couple of HTP strand bundles from the Sterling core to tighten the core/cover fit. First time around It wasn't quite as firm as I wanted , version 2 was super firm with a little more HTP core added. In retrospect I don't think it mattered. Based on the core spec I was getting a 9500 lb MBS strength bridge with excellent resistance to flex fatigue. I chose the polyester Sterling HTP 10mm cover because it is beefy and made sense as abrasion and UV protection for the core. It likely wears my swivel eye faster than the smoother cover stock TM bridge.
How did I feel climbing on it? Despite the theoretical specs being good I always carried some small amount of anxiety about it. It's the psychological aspect of being a tree climber, there are many factors that can undermine your confidence on any given day. It's something I learned in my first year of rope and harness climbing, if I have any underlying "issues" on my mind they will be forced to the surface when I'm on rope. I've found that I will often rationalize anxiety onto my gear. It's very wise for a climber to be continually mindful about their life support gear condition but I think (for me anyway) there is a lot of projection of non-climbing related issues on to my gear, and tree parts in general ;-)
With that out of the way, back to home-made cordage. When I retired the first bridge I dissected it to see what was going on. The Dyneema looked generally good. There was some subtle abrasion on the surface of the Dyneema braid. The interior of the braid looked brand-new. It could be that the HTP core fibers added in for fit abraded the Dyneema. Or it could be that contact with the inside of the Sterling HTP cover did it. It's worth noting that the OG Tree Motion bridge cordage and Globe 3000 have a thin/soft intermediate "PEZ" (Polyester) sleeve. Whether it's intended or not it may reduce inner cover abrasion on the Dyneema core.
Here's my second gen composite bridge just after I built it. Met the firmness spec ;-) if that's not a stiffy I don't know what is!
Here's a close look at the roughed up surface of the braided Dyneema core after dissection of my gen 1 bridge after plus 1-year use.
Interior fibers looked good
Here's the recently retired cordage, the cover is in excellent condition, looks much better than Globe 3000 would after a year of use.
This is the pinch point where the cordage exits the TM front D opening. Actually looks a little better than what you'll see on a retired Globe 3000 bridge. On inspection of my dissected gen 1 bridge the condition of the Dyneema in the pinch point was excellent.
Swivel eye wear area is excellent. Some flattening (expected), minor surface abrasion and the typical polishing from the DMM alloy swivel eye. I'd like to dissect and examine the core but I'm also curious what the current break strength is ;-) In hand the bridge still feels bomber.
This could all be just a "Who cares? Just buy the stock bridge!" I'm practically (in the true meaning of the word) in agreement with that but it is interesting to examine the results of these experiments.
-AJ
The cordage is built with a braided Dyneema SK78 core (stripped from Samson WarpSpeed II 9.5mm sailing line) fit into a cover from a core stripped Sterling HTP 10mm line. I added a couple of HTP strand bundles from the Sterling core to tighten the core/cover fit. First time around It wasn't quite as firm as I wanted , version 2 was super firm with a little more HTP core added. In retrospect I don't think it mattered. Based on the core spec I was getting a 9500 lb MBS strength bridge with excellent resistance to flex fatigue. I chose the polyester Sterling HTP 10mm cover because it is beefy and made sense as abrasion and UV protection for the core. It likely wears my swivel eye faster than the smoother cover stock TM bridge.
How did I feel climbing on it? Despite the theoretical specs being good I always carried some small amount of anxiety about it. It's the psychological aspect of being a tree climber, there are many factors that can undermine your confidence on any given day. It's something I learned in my first year of rope and harness climbing, if I have any underlying "issues" on my mind they will be forced to the surface when I'm on rope. I've found that I will often rationalize anxiety onto my gear. It's very wise for a climber to be continually mindful about their life support gear condition but I think (for me anyway) there is a lot of projection of non-climbing related issues on to my gear, and tree parts in general ;-)
With that out of the way, back to home-made cordage. When I retired the first bridge I dissected it to see what was going on. The Dyneema looked generally good. There was some subtle abrasion on the surface of the Dyneema braid. The interior of the braid looked brand-new. It could be that the HTP core fibers added in for fit abraded the Dyneema. Or it could be that contact with the inside of the Sterling HTP cover did it. It's worth noting that the OG Tree Motion bridge cordage and Globe 3000 have a thin/soft intermediate "PEZ" (Polyester) sleeve. Whether it's intended or not it may reduce inner cover abrasion on the Dyneema core.
Here's my second gen composite bridge just after I built it. Met the firmness spec ;-) if that's not a stiffy I don't know what is!
Here's a close look at the roughed up surface of the braided Dyneema core after dissection of my gen 1 bridge after plus 1-year use.
Interior fibers looked good
Here's the recently retired cordage, the cover is in excellent condition, looks much better than Globe 3000 would after a year of use.
This is the pinch point where the cordage exits the TM front D opening. Actually looks a little better than what you'll see on a retired Globe 3000 bridge. On inspection of my dissected gen 1 bridge the condition of the Dyneema in the pinch point was excellent.
Swivel eye wear area is excellent. Some flattening (expected), minor surface abrasion and the typical polishing from the DMM alloy swivel eye. I'd like to dissect and examine the core but I'm also curious what the current break strength is ;-) In hand the bridge still feels bomber.
This could all be just a "Who cares? Just buy the stock bridge!" I'm practically (in the true meaning of the word) in agreement with that but it is interesting to examine the results of these experiments.
-AJ
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