servo saver for dig

[Bray D]

I've been running a Hurtz V2 dig in my project truck with a rigid link, full size servo (20kg) and no servo saver. It binds so hard when it shifts (and the cogs don't align) that it deflects the servo mounting plate. It's crazy.

It pushes so hard that it can lock the rear on carpet even without the teeth engaged (friction only from pressing the shift collar against the drive dog so hard), so engaging while rolling/under throttle isn't even a solution.

I put a fixed spring servo saver on it, but it's not adjustable and the spring is so stiff that it'll still deflect the mount. I like the low profile of this style of SS though, so I'm hesitant to go to the V seat type.

What are you guys running on your dig to keep this from happening? Are there super light servo savers out there? Just run a weaker servo?

 

[twade984]

Have you adjusted the end points? It sounds like maybe the servo is traveling to far in either direction.


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[indybama]

I was goina suggest that very thing. I dont run a servo saver on dig or the selectable o/d on the phoenix. Just adjust your endpoints so its not flexing the mount, but it engages the dig easily

 

[Bray D]

Endpoints are dialed. The binding occurs when the shift collar hits the flat end of the drive dogs. Once everything spins and it snaps into place, the mount is relaxed and everything is happy.

Unfortunately nothing spins when I shift to locked rear dig, and it just stays bound up (not properly engaged yet locking up the rear).

There’s no way to avoid this (that I’m aware of) without running a servo saver or some sort of ‘soft’ linkage.

I think Axial specs the Capra with a SS on the dig horn. Does anyone know what spline count that is?

 

[ferp420]

i dont have the hurts dig but i have several 2 speeds i ether use a flexible wire so when pushing on the shift fork the wire flexes
if i dont have alot of room ill run 2 springs on the shift shaft and position the servo between the 2 springs and the springs do the actual shifting

you could also use the trx4 diff lock cable and modify it to work with your dig that way if it pushes to hard the cable will flex

 

[Redharris]

I've been running a Hurtz V2 dig in my project truck with a rigid link, full size servo (20kg) and no servo saver. It binds so hard when it shifts (and the cogs don't align) that it deflects the servo mounting plate. It's crazy.

It pushes so hard that it can lock the rear on carpet even without the teeth engaged (friction only from pressing the shift collar against the drive dog so hard), so engaging while rolling/under throttle isn't even a solution.

I put a fixed spring servo saver on it, but it's not adjustable and the spring is so stiff that it'll still deflect the mount. I like the low profile of this style of SS though, so I'm hesitant to go to the V seat type.

What are you guys running on your dig to keep this from happening? Are there super light servo savers out there? Just run a weaker servo?

Try putting your Dig on a Potentiometer. That way your servo doesnt Slam the Tranny in and out of Dig at Warp speed. Ive found that its a lot easier on the Servo, on the plastics, on the Transmission, and it works Great on my SCX10iii JL. You still need to set end points, but the slow speed at which the servo moves when actuated by the Pot, makes the whole sequence nice and smooth.

 

[meatmonkey]

I run the cheap Kimbrough servo savers on my dig and locker servos to help address exactly your concern. Mine are the 24 spline red ones for my preferred Hitec 225mg servos. They offer a few other options as well. Works well.

On my Spectrum rugged I have the servo speed set at 50% on the radio to also help minimize the dog's clashing during cycling of the dig.

 

[Bray D]

Good stuff. Thanks for the ideas.

I have a GT5 and could totally run it off of a pot. I may do that and see how I Iike it.

I went to my LHS and they sold me a Kimbrough 124, large with a strong spring. Checking their site, it looks like they make a small for a 25t servo as well. I assume small/medium/large translates to spring strength. I may put a small on it just for kicks. Cheap learning experience. I’ve never messed with these things before.

 

[Redharris]

I think Axial specs the Capra with a SS on the dig horn. Does anyone know what spline count that is?

Axial is using Spektrum Servos, These days anyway.
I believe Spektrum servos have 23 splines.
I Know Futaba is 25
Hitech is 25.
My Reefs servo is MICRO 25 spline. I had to search around to find a 25 spline micro adapter in order to use the stock Axial Servo Saver. It ended up being a Printed part, so I dont know how durable its going to be in the long run.

 

[Bray D]

Good to know. I went ahead and ordered a 25 spline Kimbrough small servo saver. I'll toss that on and see how it does. If it's still a bit harsh with my 3 position switch, I'll put it on a pot channel and see how I like that.

Thanks again everyone. I'm pretty confident I'll get it working how I want at this point.

 

[indybama]

I have mine on ch6 on the gt5. Tryed it on ch3, so it was 4wd or dig, but i couldnt get it dialed in right n screwed myself on c3 course 2 at scale nats. Went back to the pot n it works great

 

[chilly]

I have a capra and a Phoenix and the capra dig is much more rudimentary and I can see it doing what you are saying - not locking in instantly and ending up loading the servo. Also sticks somewhat - somethings have to roll back a bit to disengage. The Phoenix is like butter - it goes in right in and out on the fly. Much higher quality system. I'm literally using garbage plastic gear spectrum $3.50 servos off an Arrma e-brake on the phoenix.

I'm new to this though - so not sure what Hertz is yet - so forgive me if I missed your point entirely!

 

[indybama]

Some people have mentioned before about filing the edges of the dogs. Doesnt take much, just enuf to smooth the corner off. That seems to help it engage smoother. Personally, ive never had to do this, but may be worth a shot

 

[durok]

I'm new to this though - so not sure what Hertz is yet - so forgive me if I missed your point entirely!

Vanquish makes the Hurtz Dig in VFD and v2 versions, all-aluminum.

https://www.vanquishproducts.com/search.php?search_query=DIG&x=0&y=0

 

[Bray D]

Kimbrough 114 vs 124. Feels a good bit lighter.

I’ll get it installed and put power to it again tonight. This may be the ticket.

edit: Got it together and it's just about perfect. I can see just a smidge of deflection in the mount and it's not too violent when it snaps into place. I think I'll run it like this for now.

I will say that the 'horn' length is almost too short. Barely enough clearance for my rod end at both ends of the travel. I wish they had this SS body size with a longer horn. Either way, it works so I'm running it.