|Front View: Closed||Rear View: Closed|
|Front View: Open for Rigging||Rear View: Open for Rigging|
I acquired my GM Climbing from Emma Xiao in 2017.
The ascender is left-handed, as are most chest ascenders I have seen. The ascender is 118 mm. tall, 81 mm. wide, 35 mm. thick, and weighs 159 g. The ascender shell is subtriangular blue anodized shape bent from 4 mm. aluminum sheet. The rope channel is formed by bending the right side of the ascender into a U. The rope channel is 18 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 attachment points appear to be ovals distorted by the stamping operation. The lower attachment point measures 23.0 by 20.0 mm. and the upper 17.0 by 16.0 mm. 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 pivot is centered 48 mm. from the inside of the rope channel.
The cam is a stainless steel casting with an open web. The cam radius increases from 38 to 57 mm. over an angle of 44°, giving a 28° cam angle. The cam has number of small conical teeth, all of which have their axes approximately aligned with the cam axle. The tooth pattern is (3)^3(1S1)^5(3)^2.
A plastic-covered spring-loaded manual safety tab is mounted on the bottom of the cam with a steel semi-tubular rivet. The normal action of the spring holds the safety against the cam. When the cam is opened, the shell interferes with the safety bar, thus preventing opening the cam. If the safety bar is moved away from the cam (opposing the spring), it will clear the shell and the cam will open. At full open the safety can be released and the spring will hold the safety against the back of the shell. This provides a means of locking the cam open.
The front of the ascender is printed with an up-pointing arrow labeled "UP," "MAX 4kN," and "ROPE: Ø 8-12mm." The rear is printed with the GM Climbing logo, "GM CLIMBING," "0417," "CE1019," and "EN 567."
The GM Climbing is one of the following group of closely-related chest ascenders:
I obtained most of these from China. The others (e.g., the Rock Empire obtained from the Czech Republic, the Vento from Russia) were made in China as well. These are all well-made ascenders and the prices that I paid, even with shipping, were far below those of the European-made equivalents. One potential concern is that we don't have the experience with Chinese metallurgy and quality control that we have with American and European devices, but I have no evidence suggesting that the metallurgy is unacceptable and the quality certainly appears to be fine. I'm not making any recommendation on this point one way or the other.
All sharp edges have been removed, except for those on the inside of the attachment holes on a few of these. The user should round the attachment holes with a Swiss file.
The cams are all very well made. There are two distinct cam types, "symmetrical" and "asymmetrical." The reverse side behind the cam face is parallel to the cam axle on the symmetrical cams, and sloped on the asymmetrical cams. This has no practical significance. The asymmetrical cams have a (3)^3(2)(1S1)^4(3)^2 tooth pattern while the slot in the symmetrical cams is slightly longer (extending to between the top tooth pair), giving a (3)^3(1S1)^5(3)^2 tooth pattern. This also has no practical significance.
Another minor difference is that the cam rivet on the Yoke has a smaller head than the ones on the others.
All of these have aluminum tab cam safeties, but the ones on the GM Climbing and Rock Empire are plastic-covered. I don't find a particular advantage or disadvantage to the plastic tab, but one may have a personal preference. Mine is to save weight by choosing one without the plastic cover.