How to use DMM Cam, warning, lifespan, inspection, care and maintenance with instructional pictures.
The 3CU 1 is officially retired.You've found a page of history! The 3CU 1 is no longer produced by DMM and it is not available to buy from major online retailers. You can still check out all the specs and claim your ownership.
Conventional cams work well in cracks and open breaks, but pockets and constricted placements can cause problems. So what can you do if the cam is too wide to fit? The answer is obvious really: reduce the number of cam lobes.
3CUs have three cam lobes instead of four. This means the head of the cam is significantly narrower and will fit in much tighter placements.
We’ve built these neat little units to exactly the same specification as the 4CUs but limited the size range to six options running from 0 up to 1.75.
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|Weight (g / oz)|
Weight (g / oz)
In grams and ounces, the weight, as stated by the manufacturer/brand.
|84.0 g / 2.96 oz|
|Cam Head||3 lobes, single axle|
|Stem||Flexible double stem|
|Sling||Dyneema (double loop)|
|Camming Angle||14° |
|Active Strength|| 12 kN|
Single loop strength rating is 12 kN and double loop strength rating is 14kN.
|Cam Range (mm / in)|
Cam Range (mm / in)
In millimeters and inches, the maximum dimensions of the cam lobes when shut tight and fully extended. Since the "usable" range is so debatable, all manufacturers now list the full dimensions to avoid confusion.
If a manufacturer lists the usable range, we'll include it here as well (this is now very rare).
| Total dimensions|
19 mm x 29 mm / 1 in x 1 in
Summary: The most noticeable thing about the DMM 3CUs and 4CUs are their bright colors, which makes picking the correct size from a crowded rack a breeze. Each unit's cam lobes, trigger bar, and thumb bar are anodized to match, and, yes, the doubled sling blends right in too. The trigger bar allows for a bit of independent cam manipulation -- rare on a U-stem unit. Another unique feature are the cam lobes (with integrated cam stops), which are wide when fully retracted and taper to a more standard width near the end of their range. When the cam is placed tightly, there is more cam surface against the rock for greater grip -- great for parallel cracks, but if the crack is flared or irregular the cams will sit awkwardly. Another drawback is the trigger bar's tendency to slide up the trigger wires toward the head. The extra step of pulling the trigger back into position is easy, but a burden on pumpy routes.
Pros: Extendable sling; trigger bar allows for some independent cam action; great color coding; cam stops; light.
Cons: Poor performance in flared or awkward placements; trigger bar slides down.
The UIAA equipment standard provides a baseline for equipment performance in a test lab under controlled conditions on new equipment. Although these test conditions are relevant to the conditions encountered climbing, conditions encountered at the crags and the condition of the equipment are equally important. This recommendation from the UIAA member federation The British Mountaineering Council (BMC) provides vital equipment information that is NOT explicitly addressed in the standard, particularly failure modes of the equipment and recommendations for the use, inspection, maintenance, and retirement of equipment.
A pictoral representation of the UIAA-125 and EN-12276 standards for frictional anchors (which includes SLCD's [cams] and Ballnuts).