On sport climbs you clip bolts that have been drilled into the rock, but on crack climbs and numerous other traditional
or gear routes you’ll need a rack of nuts and cams to fix in cracks and other features, protecting yourself as you climb. Nuts are considered “passive
protection” because they lack moving parts. Cams are “active protection,” because they mechanically alter their shape to adjust to crack sizes, and
are spring-loaded to lock into a placement.
Nuts are wedge-shaped bits of metal that you jam in constrictions
in a crack, similar to a cork in a bottle. The first nuts were actual hex nuts from machine bolts with the threads filed out, and slung with cord,
hence the name now in general use. You’ll find nuts in three basic shapes: the wedge, generically referred to as stoppers (Stopper is a specific name
for a branded product); Tri-cams (a brand name, but now used generically for the shape); and hexes.
Wedges, or stoppers, can be straight-sided or curved. The curved ones present three points of contact instead of two, making
them the most stable, and the curve often fits more naturally in cracks, which are seldom perfectly straight. Exceptions are the “micro” wedges, sometimes
made of brass or bronze, which only come with straight sides. A well- rounded rack will have two full sets (usually 10 or so to a set) of wedges, and
one set of micros.
Hexes are the odd-looking six-sided nuts. These work two ways. You can jam them into constrictions, or cam them into nearly
parallel-sided cracks. Sounds great, but because wedges and cams collectively do about everything a hex can, and usually better, hexes have fallen
from favor. They are, however, invaluable for building a lightweight rack. The larger sizes can cover the range of heavier cams. Hexes also can fit
into cracks and pockets that are too oddly shaped for nuts or cams. Plus, you can buy five hexes for the price of one cam.
Tri-cams are pyramid-shaped nuts that, like hexes, can be placed either to cam or wedge in a crack. These are usually used
when other protection pieces aren’t fitting well, such as in solution holes. On certain climbs, having a Tri-cam means the difference between a dangerous
runout and having great protection.
Cams have spring-loaded lobes that expand and press against the sides of the crack, locking them in place. The more weight you put on a cam, the more it
resists pulling out. To remove a cam, you simply pull a trigger and the cams retract. Because cams are so easy to place, are secure in parallel cracks
where wedges and hexes aren’t, and are easy to remove, they are the nucleus of the rack. The popularity of cams has bred a host of designs, nearly
all of them good. Look on any shop wall, and you’ll find units with four lobes, three lobes, one axle and two axles, and in sizes from smaller than
your pinky finger to as large as your head.
What to get?
Units that fit cracks one to three inches wide are generally the most useful, though if the crag you frequent has a surplus of finger or fist cracks, you’ll
need smaller or larger units. Check with a local climber or shop to see what is appropriate protection for your area. Ergonomics are another consideration.
Beefy fingers may have trouble with certain trigger configurations. Handle the gear before you buy. Does it fit your hand? Get the brand that suits
Once you pick a brand, stay with it, at least for now. If you mix up the brands, the different color coding and range of sizes are likely to be confusing—hardly
desirable when you’re pumped and need to know at a glance which unit will fit that two-inch placement.
The four-cam configuration is usually the strongest and most useful; we advise getting these to start your rack. Three-cam units (TCUs),
however, slot into cracks too shallow for most four cams, and may, depending on brand, come in a couple of sizes smaller than four-cam units.
Fortunately, such shallow and thin cracks, which tend to be most difficult, are rare on free climbs, especially at the level most people learn on.
A good beginner rack is almost or entirely made of four- cam units, with TCUs filled in later as your experience and skills grow.
Check out Rock and Ice's nuts and cams reviews.