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I acquired this pair of ascenders from Speleoshoppe in 1979.
In 1979 Jumar the Jumar 78 became available. The most distinctive difference is the color. The old light gray was replaces by a new bright yellow. In addition to the color change, numerous other changes were made to the rest of the ascender.
The frame had numerous modifications, but the general Jumar pattern remains. The most important change is the use of a new, tougher alloy. This alloy does not appear subject to brittle fracture like the gray frames were. Most of the frame has been made heavier. The rope channel is taller, and a third reinforcing rib is cast into the back of the rope channel and the back of the frame. The front strap and the strap over the upper attachment hole were thickened. The lower portion of the ascender was completely redesigned. The sling attachment hole is a 16 mm. circular hole oriented horizontally. The frame is 10.3 mm. thick at this point, giving a very good surface for attaching slings.
The cam was also redesigned. A reinforcing bar was added to the inside of the cam. The cam teeth were enlarger, and the tooth pattern was changed to (4.5)^3(4.3)^3. The entire cam, including the teeth, is very well made.
The plastic cam safety is also new. Instead of the old "straight" design, the new design has a 135° elbow. The safety to pivots at a similar location as the old safety, so the effectiveness as a safety is unchanged. The elbow allows half of the safety to sit inside the handle when not activated, so it does not interfere as easily with one's hand. A "beak" on the end of the cam safety can hold the cam in the half open position if desired. Similarly, a tab at the elbow can hold the cam 3/4 open (the rope can slip out here), and the flat between the elbow and pivot provides a full open hold.
This ascender was developed in response to reports of "gray" Jumar failures such as the ones mentioned above. The new design is substantially heavier and more rugged than the older models. When I visited Walter Marti, he let me pound on a Jumar with a sledge hammer. I gave it a number of hard blows, blows that were far worse than one would ever reasonably expect to deliver on even the hardest caving trip. The Jumar was severely mangled and distorted after I was through, but it did not crack.
The larger, more widely spaced cam teeth are less sensitive to mud than the old ones were. The "Gray" series Jumars had a partially deserved reputation for poor performance in muddy conditions. The "Yellow" series Jumars do not seem to have this stigma attached to them. I find that the "Yellow" Jumars perform better in mud than the "Gray", but I suspect that the bad reputation of the old Jumars was partly due to their being compared to knots rather than other ascenders; after all, one can virtually always get knots to work.
The elbow in the safety makes the Jumar slightly harder to use one-handed than the older gray models, but the difference probably isn't worth worrying about. The same motion can be used as on the polder Versions. On the other hand, the new design is much harder to open accidentally. This is a persuasive argument in favor of the elbow design. I don't like the beak on the safety, for the same reasons I don't like the teeth on the C.M.I. UltrAscender safety. A penknife solves the problem on this model, the improved safety on the later Jumars eliminates it completely. A few of the earlier Jumar 78s had a defective cam safety spring (Montgomery, N. and D. Mrozkowski, A Note on the Jumar, N.S.S. News, v. 39, # 1, Jan., 1981, p. 20; Montgomery, N. and D. Mrozkowski, The New Jumar, Caving International Magazine, #10, Jan., 1981, pp. 42-46). One end of the spring was too short, so the spring tended to pull through and unwind, losing its ability to function in the process. These were replaced under warranty by a newer, 1.5 mm. longer spring which cured the problem.
When the Jumar 78 came out, I bought a pair. Version B came
out very shortly thereafter, and I bought a second pair. I took
three of the ascenders and a Gossett
Box and made a climbing system based on the Cuddington 3-phase.
Since then I have done virtually all of my vertical work with
this system, or the Texas System obtained by leaving one Jumar
and the box in the truck. Because Jumars are my normal caving
ascender, I have more experience with them than with any other
devices in my collection. I have been happy with their performance
under a wide range of caving conditions, including clean ropes,
dust, mud, snow, ice, and waterfalls. I've used them on ropes
ranging from 7 mm. to 13.5 mm. including Goldline, Samson, Blue
Water II and III, PMI of various flavors, Mammut, Edelrid, and
even an oil soaked piece of manila hanging from an 1898 vintage
oil derrick. In every case, they have worked, although climbing
an iced Edelrid rope took a bit of special effort. Recently I
retired the Version A ascenders, but I haven't given up on Jumars
- I'm using Version C now. The Jumar 78 series ascenders remain
my favorite for most applications. Many other ascenders are smaller
and lighter, but in most cases I'll sacrifice space and weight
in favor of versatility and ease of use. The Jumar is strong,
well made, reliable, comfortable, easy to use, easy on ropes,
versatile, rugged, fast, and just plain feels right. Other ascenders
have many of these properties, but the Jumar puts them together
in a package that I am very happy with.
[ Top | Version A | Version C | Return to H.E.C. Ascenders ]
I acquired this pair of ascenders from Speleoshoppe in 1979.
The cam safety was modified in late 1979. The new design moved the beak from the tip of the safety to the elbow. The beak is shielded by two breakaway tabs. If the tabs are not removed, the beak is nonfunctional and the only cam hold open position is full open. If the breakaway tabs are removed, the beak is exposed and can be used to hold the cam half open. The full hold open feature remains functional.
This change eliminates my one complaint with the original Version A. Naturally, I leave the tabs in place.
[ Top | Version A | Version B | Return to H.E.C. Ascenders ]
I acquired this pair of ascenders directly from Walter Marti (inventer of the Jumar) in March, 1989. They were given to me as a gift so that I could evaluate them for the article I published in Nylon Highway #29. That article forms the basis for many of these descriptions. I also received a left handed ascender as a gift during my visit with Walter Marti in 1982. This ascender was a prototype, and had been developed for and used on an Austrian caving expedition.
This Version is identical to Version B except two holes have been drilled near the top and bottom of the rope channel, and a 4 mm. stainless steel is press fit into each hole. The pins are partially exposed on the inside of the rope channel.
There pins are added as wear resistors. Europeans usually use the Frog System for caving, and the chest ascender in the Frog tends to wear rapidly since it is moved up the rope while the cavers weight is pulling the ascender rope channel back against the rope. This causes far more ascender wear than most U.S. climbing systems. After 10 years of use, during which I wore out a dozen brake bars on my racks and several figure 8s, I did not even finish wearing through the paint on the inside of the rope channel of my Version A Jumars. The reason is twofold: using clean ropes whenever possible, and an ascending system where ascenders are not raised while they are loaded.
The steel pins will have to wear away before the aluminum rope channel can wear significantly. These pins are an excellent example of a very simple design modification which has no real disadvantages and significantly improves the overall ascender.
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©2007, Gary D. Storrick