monkeyracer
I wanna be Dave
What is a dig or disconnect?
A dig is a device attached somewhere in the driveline that disconnects power to either the rear, front or both axles to allow a special type of manuever that gives the truck a tighter turn radius.
There are typically 3 modes in the dig's operation; 4WD, Locked, and Freewheel. When in 4WD, all 4 wheels turn just as they do without a dig, shifted into Freewheel, this disconnects the dig axle (typically the rear) and allows it to spin freely from the other axle, shift into Locked, and the dig axle is held in place as if a brake were applied to it.
Usually a seperate servo and a 3 channel radio are required to be able to shift the dig between the 3 positions (if your radio is only equipped with a 2 position 3rd channel, like the Traxxas TQ3, you may lose one of the 3 positions, usually freewheel. There are some threads in the "Electronics" section that show how to obtain 3 positions on the 3rd channel, so it's worth a look in that section to find out how.)
Ok, so when do I use one?
Recently, more and more competitions have "dig lines" or lines that would be almost impossible to complete without a dig, usually tight turns or awkwardly positioned gates.
Shifting the dig into locked rear is similar to applying the parking brake in a 1:1 vehicle. When throttle is applied, the front tires tend to slip and if there is any turn angle on the front wheels, the vehicle will pivot in that direction, allow the crawler to rotate without needing a long distance.
If you've ever been to a comp, the guys that usually do well, have digs, watch how their trucks behave, and you'll start to learn when to use dig to prevent having to take a reverse penalty to line the truck back up.
Another situation where a dig is usefull is a steep incline like a tall curb, for example. The dig can be used to help climb a near verticle obstacle, by using front drive only (freewheel) to help pull the rig over the rock (where if the rear wheels were driving, it would flip the rig over.)
What else should I know about digs?
Well, there's a whole forum at your disposal, so use the search button at the top of this page. One thing I recommend is:
Get (or mod) a radio system that has end point adjustments for the 3rd channel. This helps save the servo from burning out. Some people use a servo strecher to do the same thing.
You want the servo to positively shift the dig into the correct position, but not hum after it's shifted. The humming is the servo trying to pull the shifter further and causes stress on the servo board and motor. It takes a little time to get the end points adjusted correctly, but well worth it in the end. Some companies have a walkthrough on how to set the end points for their dig.
Another thing to add, the location of the servo can also affect the performance of the dig and the truck itself. Mounting the servo to the chassis may allow it to be mounted lower, but when the chassis flexes it may inadvertantly shift the dig into a different position. Mounting the servo on top of the transmission is a good way to prevent chassis flex deflection, but may raise your center of gravity.
A good balance is the new DNA servo mount, the Eritex servo mount, and the type of mount the 3Racing unit uses. These all allow the servo to mount low, to keep COG low, while maintaining a stiff, strong mount to prevent flex deflection. Beware that a weak transmission mount that flexes is just as bad as a chassis mounted servo mount, so make sure the material used is strong enough, and the screws are tightened correctly.
Now, since a dig is pretty much mandatory at comps now. I am looking into getting one finally, but want to make the best decision on which one to get. Here's what research I've done, but if I am missing something, please let me know.
There are basically these options for dig:
DNA/VF (DNA300HD)
Eritex (HRD 3.1)
Vanquish Products (Waiting to be finalized)
Hot Racing (SCP39L01)
CKRC FT (CK1006)
3Racing (AX10-29)
Montrucks Dual Dig (MT Dual Dig)
RC4WD R2 with Dig (X-0361 open, X-0493 enclosed)
Stage 3 Racing (Link not provided, lockergate and dig.gate scandals)
Make My Own (My Link)
Make Your Own Driveshaft dig (Sticky Here)
Here's what I found from searches on pro's and con's:
DNA/VF (DNA300HD)
Pros:
Well thought out design
Nice machined parts
Fully enclosed
Color options
4 points of engagement
New steel internals
Now comes with servo mount
DNA customer service
Replaces the stock outdrive with a stronger piece
Servo mounts to transmission rather than chassis
Cons:
A little on the higher priced side
Needs a torquier servo to keep it engaged
A little on the large side
May have to trim the case if you have triangulated lower links
Drive shaft moves with dig position
Eritex (HRD 3.1)
Pros:
Small size
Hex/Collar style = low torque engagements
Almost Fully Enclosed
Nice machined parts
6 points of engagement
Very well thought out design
Eritex customer service
Servo mounts to transmission rather than chassis
Drive shaft does not move with dig position
Cons:
The most expensive MSRP out of the ones I've listed
Servo mount is extra money (or just make your own)
Out of stock right now (Gerame is working on them though)
High torque servos may cause binding issues
May need a "Dig Condom" to protect from dust and dirt entering the top of the unit.
Hot Racing (SCP39L01)
Pros:
Low price
Steel internals
Once end points are dialed in, parts polished, and output beveled works great
Fully enclosed
Replaces the stock outdrive with a stronger piece
Cons:
HR's questionable design-jacking - seems to be a copy of one of the other digs here (not the only thing they've copied)
Servo mount designed for stock chassis
Needs a little massaging to get it to work well (polish and beveling)
Only 2 points of engagement - may need a "reverse bump" to disengage
Hot Racing (lack of) customer service
Drive shaft moves with dig position
CKRC FT (CK1006)
Pros:
Small size
Spur side mounted (keeps motor weight forward)
Low price
Can be added to any other dig to have dual dig
Cons:
Optional servo mount is extra
Open to dust and dirt to clog the dogs
Not seeing a lot of positive threads here on this dig
Needs the upgrade outdrive = more money
Drive shaft moves with dig position
3Racing (AX10-29)
Pros:
Small Size
Includes short aluminum drive shaft and transmission mounted servo mount
Decent price, about mid-range
Cons:
Not a lot of positive threads here about this dig
Takes quite a bit more work to get it working
Unsure on # of points of engagement
Need to get the front drive shaft to match or have mismatched shafts
3Racing (overseas) customer service
Drive shaft moves with dig position
Montrucks Dual Dig (MT Dual Dig)
Pros:
Dual dig design
Can use one side or the other alone if needed
Cons:
Very close design to some of the other digs
Open to dust and dirt to clog the dogs
Higher price
New, not a lot of reviews on this dig
Needs 4ch to get both digs working
Only 2 points of engagement
Make your own servo mount
Drive shaft moves with dig position
RC4WD R2 with Dig (X-0361 open, X-0493 enclosed)
Pros:
Good price for a trans/dig combo
Fully Enclosed (X-0493)
Nice machined parts
Low profile transmission
Cons:
Needs a new skid plate to mount to
Not a lot of spur/pinion combos for the motor
Open design allows dust and dirt in (X-0361)
Only 2 points of engagement
Servo mount is extra
Drive shaft moves with dig position
Stage 3 Racing (Link not provided, lockergate and dig.gate scandals)
Pros:
5 points of engagement
Nice machine work
Servo mount included
Replaces the back of the stock transmission case (front case is optional)
Replaces the stock outdrive with a stronger piece
Removeable rear plate for easy access to internals
Cons:
Blatant copy of the DNA dig (didn't ask permission to improve it)
Questionable business practices (Mass PM scandal)
S3R - Banned from this forum -nuff said
Basically it's a great unit, but a bad company
Make My Own (My Link)
Pros:
Inexpensive
Experience of building it myself
12 points of engagement
Drive shaft doesn't move with dig position
Cons:
No machine shop to get precision
Lack of precision causing binds
No replacement parts available, I'd have to start over if something breaks
Make Your Own Driveshaft dig (Sticky Here)
Pros:
Very inexpensive
Experience of building it yourself
Cons:
Bulky on the driveshaft, may cause clearance issues
May lose one of the three positions depending on how you make it
Snap a driveshaft and you'll have to start over basically
The DNA and Eritex look to be the best, the Vanquish has potential as well. These 3 companies have spent the time to develop their units, and all 3 have excellent customer support. The rest of the digs all have a suspiciously similar design. The RC4WD version replaces the stock Axial transmission. All digs take a little time to set them up and dial in the end points, some take less than others. Pricing on the above list ranges from $40ish to over $100. I wanted to know what was the best bang for the buck that I wouldn't have to mess with every comp. However, I've seen plenty of positive reviews on some of the lower priced digs that with the price, are tempting to get. I want everyone's opinion though.
If I am missing a pro or a con, please let me know. Also, please leave the S3R bashing out of this thread, they're banned, I don't want to be as well.
Basically, post what dig you have personal experience with, and what you think are the pros and cons of the dig. If you have modded it to work well, please post that as well. Also, post what servos you've used, and what works well and what doesn't. The price of the dig servo should be accounted for when shopping for a dig.
A dig is a device attached somewhere in the driveline that disconnects power to either the rear, front or both axles to allow a special type of manuever that gives the truck a tighter turn radius.
There are typically 3 modes in the dig's operation; 4WD, Locked, and Freewheel. When in 4WD, all 4 wheels turn just as they do without a dig, shifted into Freewheel, this disconnects the dig axle (typically the rear) and allows it to spin freely from the other axle, shift into Locked, and the dig axle is held in place as if a brake were applied to it.
Usually a seperate servo and a 3 channel radio are required to be able to shift the dig between the 3 positions (if your radio is only equipped with a 2 position 3rd channel, like the Traxxas TQ3, you may lose one of the 3 positions, usually freewheel. There are some threads in the "Electronics" section that show how to obtain 3 positions on the 3rd channel, so it's worth a look in that section to find out how.)
Ok, so when do I use one?
Recently, more and more competitions have "dig lines" or lines that would be almost impossible to complete without a dig, usually tight turns or awkwardly positioned gates.
Shifting the dig into locked rear is similar to applying the parking brake in a 1:1 vehicle. When throttle is applied, the front tires tend to slip and if there is any turn angle on the front wheels, the vehicle will pivot in that direction, allow the crawler to rotate without needing a long distance.
If you've ever been to a comp, the guys that usually do well, have digs, watch how their trucks behave, and you'll start to learn when to use dig to prevent having to take a reverse penalty to line the truck back up.
Another situation where a dig is usefull is a steep incline like a tall curb, for example. The dig can be used to help climb a near verticle obstacle, by using front drive only (freewheel) to help pull the rig over the rock (where if the rear wheels were driving, it would flip the rig over.)
What else should I know about digs?
Well, there's a whole forum at your disposal, so use the search button at the top of this page. One thing I recommend is:
Get (or mod) a radio system that has end point adjustments for the 3rd channel. This helps save the servo from burning out. Some people use a servo strecher to do the same thing.
You want the servo to positively shift the dig into the correct position, but not hum after it's shifted. The humming is the servo trying to pull the shifter further and causes stress on the servo board and motor. It takes a little time to get the end points adjusted correctly, but well worth it in the end. Some companies have a walkthrough on how to set the end points for their dig.
Another thing to add, the location of the servo can also affect the performance of the dig and the truck itself. Mounting the servo to the chassis may allow it to be mounted lower, but when the chassis flexes it may inadvertantly shift the dig into a different position. Mounting the servo on top of the transmission is a good way to prevent chassis flex deflection, but may raise your center of gravity.
A good balance is the new DNA servo mount, the Eritex servo mount, and the type of mount the 3Racing unit uses. These all allow the servo to mount low, to keep COG low, while maintaining a stiff, strong mount to prevent flex deflection. Beware that a weak transmission mount that flexes is just as bad as a chassis mounted servo mount, so make sure the material used is strong enough, and the screws are tightened correctly.
Now, since a dig is pretty much mandatory at comps now. I am looking into getting one finally, but want to make the best decision on which one to get. Here's what research I've done, but if I am missing something, please let me know.
There are basically these options for dig:
DNA/VF (DNA300HD)
Eritex (HRD 3.1)
Vanquish Products (Waiting to be finalized)
Hot Racing (SCP39L01)
CKRC FT (CK1006)
3Racing (AX10-29)
Montrucks Dual Dig (MT Dual Dig)
RC4WD R2 with Dig (X-0361 open, X-0493 enclosed)
Stage 3 Racing (Link not provided, lockergate and dig.gate scandals)
Make My Own (My Link)
Make Your Own Driveshaft dig (Sticky Here)
Here's what I found from searches on pro's and con's:
DNA/VF (DNA300HD)
Pros:
Well thought out design
Nice machined parts
Fully enclosed
Color options
4 points of engagement
New steel internals
Now comes with servo mount
DNA customer service
Replaces the stock outdrive with a stronger piece
Servo mounts to transmission rather than chassis
Cons:
A little on the higher priced side
Needs a torquier servo to keep it engaged
A little on the large side
May have to trim the case if you have triangulated lower links
Drive shaft moves with dig position
Eritex (HRD 3.1)
Pros:
Small size
Hex/Collar style = low torque engagements
Almost Fully Enclosed
Nice machined parts
6 points of engagement
Very well thought out design
Eritex customer service
Servo mounts to transmission rather than chassis
Drive shaft does not move with dig position
Cons:
The most expensive MSRP out of the ones I've listed
Servo mount is extra money (or just make your own)
Out of stock right now (Gerame is working on them though)
High torque servos may cause binding issues
May need a "Dig Condom" to protect from dust and dirt entering the top of the unit.
Hot Racing (SCP39L01)
Pros:
Low price
Steel internals
Once end points are dialed in, parts polished, and output beveled works great
Fully enclosed
Replaces the stock outdrive with a stronger piece
Cons:
HR's questionable design-jacking - seems to be a copy of one of the other digs here (not the only thing they've copied)
Servo mount designed for stock chassis
Needs a little massaging to get it to work well (polish and beveling)
Only 2 points of engagement - may need a "reverse bump" to disengage
Hot Racing (lack of) customer service
Drive shaft moves with dig position
CKRC FT (CK1006)
Pros:
Small size
Spur side mounted (keeps motor weight forward)
Low price
Can be added to any other dig to have dual dig
Cons:
Optional servo mount is extra
Open to dust and dirt to clog the dogs
Not seeing a lot of positive threads here on this dig
Needs the upgrade outdrive = more money
Drive shaft moves with dig position
3Racing (AX10-29)
Pros:
Small Size
Includes short aluminum drive shaft and transmission mounted servo mount
Decent price, about mid-range
Cons:
Not a lot of positive threads here about this dig
Takes quite a bit more work to get it working
Unsure on # of points of engagement
Need to get the front drive shaft to match or have mismatched shafts
3Racing (overseas) customer service
Drive shaft moves with dig position
Montrucks Dual Dig (MT Dual Dig)
Pros:
Dual dig design
Can use one side or the other alone if needed
Cons:
Very close design to some of the other digs
Open to dust and dirt to clog the dogs
Higher price
New, not a lot of reviews on this dig
Needs 4ch to get both digs working
Only 2 points of engagement
Make your own servo mount
Drive shaft moves with dig position
RC4WD R2 with Dig (X-0361 open, X-0493 enclosed)
Pros:
Good price for a trans/dig combo
Fully Enclosed (X-0493)
Nice machined parts
Low profile transmission
Cons:
Needs a new skid plate to mount to
Not a lot of spur/pinion combos for the motor
Open design allows dust and dirt in (X-0361)
Only 2 points of engagement
Servo mount is extra
Drive shaft moves with dig position
Stage 3 Racing (Link not provided, lockergate and dig.gate scandals)
Pros:
5 points of engagement
Nice machine work
Servo mount included
Replaces the back of the stock transmission case (front case is optional)
Replaces the stock outdrive with a stronger piece
Removeable rear plate for easy access to internals
Cons:
Blatant copy of the DNA dig (didn't ask permission to improve it)
Questionable business practices (Mass PM scandal)
S3R - Banned from this forum -nuff said
Basically it's a great unit, but a bad company
Make My Own (My Link)
Pros:
Inexpensive
Experience of building it myself
12 points of engagement
Drive shaft doesn't move with dig position
Cons:
No machine shop to get precision
Lack of precision causing binds
No replacement parts available, I'd have to start over if something breaks
Make Your Own Driveshaft dig (Sticky Here)
Pros:
Very inexpensive
Experience of building it yourself
Cons:
Bulky on the driveshaft, may cause clearance issues
May lose one of the three positions depending on how you make it
Snap a driveshaft and you'll have to start over basically
The DNA and Eritex look to be the best, the Vanquish has potential as well. These 3 companies have spent the time to develop their units, and all 3 have excellent customer support. The rest of the digs all have a suspiciously similar design. The RC4WD version replaces the stock Axial transmission. All digs take a little time to set them up and dial in the end points, some take less than others. Pricing on the above list ranges from $40ish to over $100. I wanted to know what was the best bang for the buck that I wouldn't have to mess with every comp. However, I've seen plenty of positive reviews on some of the lower priced digs that with the price, are tempting to get. I want everyone's opinion though.
If I am missing a pro or a con, please let me know. Also, please leave the S3R bashing out of this thread, they're banned, I don't want to be as well.
Basically, post what dig you have personal experience with, and what you think are the pros and cons of the dig. If you have modded it to work well, please post that as well. Also, post what servos you've used, and what works well and what doesn't. The price of the dig servo should be accounted for when shopping for a dig.
Last edited:
