What is DIG?
The term "dig" comes from the fact that if only 1 set of tires are spinning (front or rear); they tend to dig a hole in the dirt. If only the front tires are spinning, it is called a front dig. If only the rear tires are spinning, it is called rear dig. Sometimes it is advantageous for the unpowered axle to be locked and dragged by the powered axle. This is called locked dig. Other times, the unpowered axle is left to spin freely. This is called unlocked dig. Read on to see which is best to use in particular situations.
the most popular use of dig is the locked dig. Most RC crawlers with three channel radios only have a two position switch for the third channel, and locked dig is what most crawlers commonly set their rigs up for. There are three situations for which to use locked dig.
The most commonly used locked dig is the turn. Locking the rear axle and steering the front wheels to full lock will allow the crawler to pivot. Almost a perfect rotation can be achieved. Making a sharp pivot-like turn allows a driver to reduce the amount of reverses needed to line up for a gate. Each back-up costs a driver one point. Those points can quickly add up. This feature alone is worth installing dig in your crawler, as competitions are often won by just a few points.Locked Descent
The use of locked dig is during steep descents and drop offs. Locking the rear allows a crawler to slow a descent by dragging its rear down a steep slope. Slower is often better in crawling as it allows the tires to maintain traction instead of bouncing down the grade, risking a flip or rollover which will cost the driver five points. You need to be ready to throttle out if the rear loses grip and tries to swap ends with the front.Locked Climb
This is locking the rear when getting ready to attempt a steep climb. Doing this allows the front tires to bite harder and wrap up on the wheels. Then it quickly pops back into four wheel drive and uses the resulting spring to give him a little boost up a difficult slope.2 Styles of DIG System
There are two types of dig systems that are employed by RC crawlers. One is an electrical system used in crawlers that have motor driven axles such as the classic Clod Buster axles or the new Berg axles. Since these axles are motor driven, they do not have a center transmission or drive shafts tying the two together. Since no driveshaft needs to be disengaged, dig is achieved by using either a pair of separate ESCs for each axle or a switch system that cuts power to one of the motors. Mixing with a stick radio allows for use of both front and rear digs, but a pistol grip radio such as the Spektrum DX3R may also be used.
The other dig system is a mechanical type that relies on a servo to engage and disengage the drive shafts and lock the axles. This is the most popular at the moment as most completion 2.2 crawlers are shaft driven. Most of the mechanical dig systems in this article were designed to be used in the ultra popular Axial AX10 crawler, but can also be used in other crawlers with a bit of imagination. Currently the mechanical dig systems for shaft driven crawlers are front dig only.source:rc411.com