Dig: What To Expect

[Knarly Nerd]

I'm finishing up a Berg/BJ4 using a Holmes Torque Master BR/XL ESC and a Punk Dig. I notice now that when dig is engaged, the selected axle doesn't lock up like it once did. During mock up with Venom Ridgeline tires, both axles would lock and drag across the carpet. In the final setup I'm using Sedona white dots which are significantly stickier than the Ridgelines. So, since there's no known electronic change, is the stickiness of the tires causing the axles to rotate with dig engaged ? I'm not sure if I should have complete lock out or not...not experienced enough with crawlers to know this. I haven't tried it outside yet.

If there is a selectable setting for more lock, would it be in the ESC? I know there are two solder bridges on the Punk Dig which can be removed to allow the axles to free-wheel but they are still intact. When dig is engaged there's resistance in the axles but just doesn't seem like enough.

[benoj]

a stickier tire definitely can affect drag brake. with a tire like the venoms they would just slide while that axle was locked and not grip anything to hard but when you go up to a stickier tire sedonas or rovers they will grip the surface more overcoming the drag brake. from my experience an esc drag brake when turned up will lock an axle up better than a dig switch which is usually just shorting the + and - motor wires

[SMR 510RR]

I bet its the tires...

Put it on a surface that isnt carpet and it will drag the rears around no problem, on dirt no question it will drag. On rocks it depends on the traction level of the rock, around here we have a lot of broken up concrete and its hard to drag the rear on that but the slicker natural stone is a different story.

[Charlie-III]

Yep, a sticky tire can make the drag brake seem to suck.

Easy test, try each type of tire while in dig, but put the rig on an incline. Most will be drag brake, some will be traction of the tire.
On flat ground, a sticky tire also helps the driven tires, thus skews the test.

Some ESC's have multiple options for drag brake. I really like what I can get from most CC ESC's, not exactly "jumping up & down" with the FX-R's.

You can also use longer brushes, or, heavier brush springs to add mechanical drag brake.
A poor alternative is to increase the tightness of the pinion/spur gear mesh to add some drag. I hesitate on this since it can harm motor bushings/bearings.

[Knarly Nerd]

I was hoping to here it was the tires. It makes sense. My next change will be motors. I've reading up on old threads and have picked a lot of good info on braking and what parts of the motor have the most affect.

Having come from the helicopter world, braking is completely foreign to me. Can you actually adjust brake amount in the ESC or is it just an on/off function?

[2500hdon37s]

what motors do you have? a higher quality motor like a Holmes Hobbies handwound motor will have much better drag brake (and more torque) than a say integy machine wound of the same turn.

[Knarly Nerd]

Originally Posted by 2500hdon37s

what motors do you have? a higher quality motor like a Holmes Hobbies handwound motor will have much better drag brake (and more torque) than a say integy machine wound of the same turn.

They're just $10.00 45T build motors from RC4WD. Figured I'd wait til last to select the right motors.

[Charlie-III]

Originally Posted by Knarly Nerd

I was hoping to hear it was the tires. It makes sense. My next change will be motors. I've reading up on old threads and have picked a lot of good info on braking and what parts of the motor have the most affect.

Having come from the helicopter world, braking is completely foreign to me. Can you actually adjust brake amount in the ESC or is it just an on/off function?

Depends on the ESC. Some have no drag brake, some have "canned profiles" (like FX-R's) others have quite a few options (most CC/CC based ESC's).

Originally Posted by 2500hdon37s

what motors do you have? a higher quality motor like a Holmes Hobbies handwound motor will have much better drag brake (and more torque) than a say Integy machine wound of the same turn.

Yep, good motors with strong brush springs can have great drag brake.

Keep in mind it's a system, a great motor may not overcome the issues with a crap ESC.
A great ESC may not overcome the issues of a so-so motor.

Using a decent/good motor with a decent (BR-XL, pretty much any Castle) ESC is a good start.

There is no "right or wrong", it's your type of terrain and what you want the rig to do.