Servo Question

[mudeatter]

Hey I'm new to the rc crawler world. I bought a 1/8 RTR last winter. Just bought it to play with and screw around on some local rocks. Recently I added 4ws to the crawler and my first run with it I cracked the plastic housing inside the servo that goes over the motor gear.(on the front) The original Servo was a crappy 9kg with metal gears. I figured it was because it was almost a year old and its stock and most stock everything is crappy. So I bought a 12kg servo with metal gears. Installed it on the front. My 3rd run on this new servo and I stripped one of the metal gears. Boooo. So I am to wonder, Is this all because they are cheap servos and I should invest in a better servo like hitec or something similar. Maybe with titanium Gears? Ive done some research and I see alot of guys run T-Pro just for the fact they are half the cost of Hitec. And I am curious why is it the front only? I havnt had any issues with the rear steering yet. I am currently running 2.8 tires with no weights and my rig is fairly light. Its a MOA Rig. Ive checked to make sure nothing was too tight, as far as my steering knuckles and tie rod / links. In case it matters, I am using a NIMH 6-Cell Battery Pack 7.2V 3800mah.

Thanks

[mudeatter]

So would I be better off on getting a servo with:

Generic Brand Servo

• Torque @ 6.0V: 220oz (16kg), Torque @ 4.8V: 206oz (15kg)
• Speed @ 6.0V: .16 sec, Speed @ 4.8V: .18 sec
• Weight: XX / XX oz
• "J" type connector with approx. 5" wire
• Standard size servo

Or something like this:

Savox SC-1256TG High Torque Titanium Gear Digital Servo .15/277

This is the Savox SC-1256TG High Torque Titanium Gear Digital Servo.

Specifications and Features:

• Combines leading edge technology with super high 12 bit (4096) resolution and titanium gears.
• Super light-weight.
• Coreless motor provides high speed, incredible efficiency, and low power consumption.
• Titanium gears ensure long life and durability.
• The aluminum case design not only looks good but also allows for cooler and smoother operating temps.
• Our servos are totally green – from materials to production, these servos are environmentally friendly.
• Ideal for steering applications in 1/8 scale buggies, monster trucks and rock crawlers.
• Dimensions(mm): 40.3x20.2x37.2
• Weight(g):52.4
• Speed(@4.8V sec/60): .18
• Torque(@4.8V oz-in): 222.2
• Speed(@6.0V sec/60): .15
• Torque(@6.0V oz-in): 277.7
• Gear: Titanium & Aluminum
• Bearing: 2BB
• Case: Aluminum
• 25 Tooth Spline

Whats the difference between analog and digital?


How about:

Hitec HS-5645MG High Torque Metal Gear Servo
Specs & Features:
· Motor Type: 3 Pole
· Bearing Type: Dual Ball Bearing
· Speed (4.8V/6.0V): 0.23 / 0.18
· Torque oz./in. (4.8V/6.0V): 143 / 168
· Torque kg./cm. (4.8V/6.0V): 10.3 / 12.1
· Size in Inches: 1.59 x 0.77 x 1.48
· Size in Millimeters: 40.39 x 19.56 x 37.59
· Weight ounces: 2.11
· Weight grams: 59.82

I am Leaning towards something with Titanium Gears since I Stripped

[Trubble]

Originally Posted by mudeatter

So I am to wonder, Is this all because they are cheap servos and I should invest in a better servo like hitec or something similar. Maybe with titanium Gears?..... And I am curious why is it the front only? I havnt had any issues with the rear steering yet...... Ive checked to make sure nothing was too tight, as far as my steering knuckles and tie rod / links.

I'm still running the stock (AS-2) servo on my crawler, and it's doing fine so far. I've even tempted fate by removing the servo saver and replaced the flimsy plastic linkage with aluminum links.
First thing that popped into my mind was the cracked housing and stripped gears, at that point, I'd wonder if your radio has EPA's (end point adjustments) that are set too far. Basically sounds like you're hitting the end of how far the steering knuckles can go, and the servo is still trying to keep going further. Why only the front, not the rear? Dunno, could be the rear arm on the servo is just a shade shorter than the front one, could be the rear servo just isn't putting out the power that the front one is and it's stalling at full bind, or could just be good old fashioned driving technique and your front tires are just the ones that find themselves between a rock and a hard place more often than the rears. If your radio has end point adjustment, I'd maybe back off on the fronts and try again, or if your radio doesn't have any way to ease up on EPA, then you could try a shorter servo arm on the front, or use a hole closer to the center to mount your linkage.

Originally Posted by mudeatter

Whats the difference between analog and digital?

Just read a long post/article on that subject, but don't remember where or how I found it, sorry. The basic gist was that analog servos reportedly have a "softer" start, and the voltage ramps up from a dead stop. Digital servos have a "harder" start where the FET's turn on full power from a dead stop. The digitals would be more accurate, but result in higher amp draw when they move. Some radio systems repotedly have trouble running digital servos, too, if the frame rate is too fast. And if you're not already running one, a move up to a more powerful servo will pretty much require an external BEC.

IMO, your best bet would be to hold off on spending a ton of money for a premium servo until you figure out your mechanical issue above.