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Cypher Chest Ascender Evo


Front View: Closed Rear View: Closed
Front View: Closed Rear View: Closed
Front View: Open for Rigging Rear View: Open for Rigging
Front View: Open for Rigging Rear View: Open for Rigging

Technical Details

I acquired my Cypher Chest Ascender Evo from Boardparadise in 2019.

Like most chest ascenders, the Evo is left-handed. This ascender is 107 mm. tall, 77 mm. wide, 37 mm. thick, and weighs 146 g.

Cam faceThe ascender shell is subtriangular gray anodized shape bent from 3.9 mm. aluminum sheet. The rope channel is formed by bending the right side of the ascender into a U. The rope channel is 15 mm. wide. The main sling attachment point is located below the cam and behind the rope channel. A second attachment point is located above the cam, also behind the rope channel. The shell is bent backwards at both points to provide clearance between the attachment slings and the main rope. This accounts for the rather large thickness of this ascender. The lower attachment point is an oval-shaped opening that measures 19.3 mm. high by 21.2 mm. wide. The upper is shaped like a rectangle with semicircular ends; it is 14.5 mm. high by 24.8 mm. wide. The left side of the shell is bent on an inclined axis to form another U. A hole drilled through both sides of the U accepts a semi-tubular rivet. The cam and cam spring are mounted on this rivet. The rivet is centered 48 mm. from the inside of the rope channel. The head of the rivet is on the front while the roll sits into a stamped depression on the back of the shell. The pivot is centered 48 mm. from the inside of the rope groove. There is a stamped cam stop near the cam pivot, but the stop does not contact the cam.

This ascender uses a standard Climbing Technology cam found on many of their handled and handleless eccentric cam ascenders. The cam is a plated skeletonized steel casting. The cam radius, measured from the pivot, increases from 38 to 57 mm. over an angle of 40°, giving a 31° cam angle. The cam has number of small conical teeth, all of which have their axes approximately parallel to the lower surface of the cam. The tooth pattern is (3.2.4)(1H1.2)^3(3.2), where the "H" stands for a 4 mm. wide, 6 mm. wide inverted subtriangular hole.

A spring-loaded manual safety is mounted on an axle riveted to the center of the cam. The normal action of the spring holds the safety against the cam. When the cam is opened, the shell interferes with the safety tab, thus preventing opening the cam. If the safety is moved away from the cam (opposing the spring), the tab will clear the shell and the cam will open. At full open the safety can be released and the spring will hold the arm against the back of the shell, locking the cam open.

The front is printed with an illustration of the ascender on rope, and an up-pointing arrow. The rear is printed with the Cypher logo, "CYPHER," "by" followed by the the CT logo, the UIAA logo, "CE0333," "Made in Italy," "CHEST ASCENDER EVO," "EN 12841:2006-B," "Rope  10≤Ø≤13 mm|100 kg | 100 kg," "EN 567:2013," "Rope 8≤Ø≤13 mm," "0004 - 151 - 17," "0317," and a book-with-an-"i" icon. The rear of the cam is stamped with "I1."

The weight ("100kg") printed on the shell can easily be
less than the weight of a fully loaded caver.


The Cypher Chest Ascender Evo is one of the following group of closely-related chest ascenders:

Image Ascender Shell Cam
Advanced Base Camp, Version A Advanced Base Camp,
Version A
Anodized Large Loop Feb. 2006
Advanced Base Camp, Version B Advanced Base Camp,
Version B
Anodized Pin Feb. 2007
Advanced Base Camp, Version C Advanced Base Camp,
Version C
Anodized Small Loop Feb. 2007
Climbing Technology Chest Ascender Evo Climbing Technology
Chest Ascender Evo
Anodized Small Loop Feb. 2014
Climbing Technology CChest Ascender + Climbing Technology
Chest Ascender +
Anodized Small Loop Jun. 2017
Climbing Technology Chest Ascender HC Climbing Technology
Chest Ascender HC
Hard Coat Small Loop Jan. 2020
Image Ascender Shell Cam
Cypher Chest Ascender Evo Cypher Chest Ascender Evo Anodized Small Loop Mar. 2017
Edelrid Windup Edelrid Windup Anodized Small Loop May 2016
Repetto Cirano Repetto Cirano Anodized Small Loop Feb. 2007
Singing Rock, Version A Singing Rock,
Version A
Anodized Pin Mar. 2012
Singing Rock, Version B Singing Rock,
Version B
Anodized Small Loop Feb. 2014

Obviously, the same people (Climbing Technology Ltd. of Cisano Bergamasco, Italy) made all of these ascenders. These are all well-made and all function smoothly. All sharp edges have been removed.

The Advanced Base Camp Version A is well-made and a number of Frog climbers have told me that they like how smoothly it functions. My testing supports their experience. The large ring on the safety is easy to grasp.

The Advanced Base Camp Version B and Singing Rock, Version A use a pin on a small safety tab. This reduces bulk, but is not as easy to grip.

The small-loop finger opening used on the remaining ascenders is not as bulky as the one on the Advanced Base Camp Version A, but some people may not like the smaller ring because it is harder to operate. I find that my fingers tend to slip off the safety. The end of the safety that locks the cam open is longer than on Advanced base Camp Versions A and B, making the lock-open more secure but also more difficult to engage or release. The shape interferes so the small-loop ascenders not have quite the smooth opening characteristics that the Advanced base Camp Versions A and B have. It also keeps this ascender from opening as far when sliding the ascender up rope. Overall, I prefer the Advanced Base Camp Version A, but John Harman, who has used these more than I have, has an opposing view. John writes:

"The "new" ABC design is much better than the old. The old design seemed to come off rope almost too easy. I never had it inadvertently come off but it never felt as secure as the Petzl. The new design has a much larger tongue that fits up inside the body and makes it much more difficult to come off rope unintentionally."

Neither of us has seen if come off accidentally, but John makes a good point about the relative security of the designs.

The small pin on the cam safety (near the rope channel) performs an interesting function: pushing down on the ring (or post) causes the safety tab to lever the cam open, but not enough to let the rope free. This provides an alternate way to "thumb" the ascender.

The cam closing stop contacts the cam at the same time that the cam face contacts the inside of the rope groove. In any case, the stop only functions when the ascender is off rope, so I consider it to be superfluous. Its only purpose is to achieve a higher strength in artificial tests prescribed by various standards.

The holes in the cam face are intended to reduce the risk of ascender slippage due to mud-caked cam teeth. The design appears superior to some, but most ropes muddy enough to stop other ascenders will stop the this one as well. If you climb muddy ropes, expect to encounter slipping problems with any eccentric cam ascender.

The Climbing Technology Chest Ascender HC has a hard-coated shell that should resist wear better than a standard anodized shell. I don't climb frog often enough to test whether this is a real advantage in the worst cave mud conditions, but it would be worth considering if you are buying a new chest ascender.

The differences between these ascenders are minor, and any of these would be a good choice. for caving. The Advanced Base Camp Version A is currently my preferred chest ascender for the rare times that I climb frog. I like the larger ring on the cam safety, but my decision is also influenced by having a spare that I can dedicate to caving use. If I were a frogger who did not have a chest ascender and needed to buy one, I would consider sacrificing the larger ring on the Advanced Base Camp Version A and choose the Climbing Technology Chest Ascender HC for the hard-coated shell.

The weight ("100kg") printed on the rear of each ascender can easily be less than the weight of a fully loaded caver. Although I know what this means, American courts may not, so I cannot recommend this ascender for heavier cavers or for expedition caving.

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