Everybody’s Scalin’ – Can You Dig It?
One of the noob questions that routinely shows up on the crawler boards (usually followed by several sarcastic answers) is “What is a Dig Unit?“.
It really is easy to forgive the question though because digs have been going the way of the dodo since competition crawling’s popularity took a nose dive following the scale boom. Still, you can find dig kits for many popular scale trucks if you just do a quick Google search.
A dig unit is a transmission modification that allows a truck to be run in different configurations- 4 wheel drive, front wheel drive with a rolling rear end, and front wheel drive with a locked up, dragging rear (i.e. the front DIGS in, get it?). The gear change is made with a shifting servo that puts it into dig mode.
Back in the motor on axle (MOA) comp crawling days you’d also have people running two separate electronic systems and therefore each system would be driven separately to create the same effect. There were also configurations that allowed them to accomplish this with one ESC by killing the rear motor when necessary.
Individual mechanics aside, there are many reasons to use a dig.
The first is improved turning radius. When the rear end drags it acts as an anchor or pivot point for the front to turn on, thereby letting the vehicle better navigate an area when real estate is at a major premium.
The second is for extreme climbing. When FWD with open rear axle mode is engaged, the front of the truck can pull the vehicle over top of an obstacle, all the while without the rear pushing. Many times this can keep the vehicle from tumbling backwards. Experienced drivers can sometimes shift into 4wd when the front gets a bite creating a slingshot effect that vaults the rig over an obstacle.
Depending on the dig configuration you are running it can also help control descents as well as make it easier to bail out of a situation and stay on all 4’s.
Hopefully that clears up some of the confusion. Digs aren’t nearly as popular as they used to be (they are actually outlawed in many scale competitions) but if you’re looking to do some hardcore crawling then installing one might just be the ticket!
Big thanks to Evol for helping with this article and showing off his trick looking Vanquish dig equipped SCX10!