Revo 3.3 HiTec Servo Upgrade (Complete)

Here are the specs for the HS-7955TG Servo's

HiTec HS-7955TG Specifications

Motor Type: Coreless
Bearing Type: Dual Ball Bearing
Speed (4.8V/6.0V): 0.19 / 0.15
Torque oz./in. (4.8V/6.0V): 250 / 333 (I think the stock servo was 80 oz)
Torque kg./cm. (4.8V/6.0V): 18.0 / 24.0
Size in Inches: 1.57 x 0.78 x 1.45
Size in Millimeters: 39.88 x 19.81 x 36.83
Weight ounces: 2.29
Weight grams: 64.92

Wow... way overkill on the servo. lol

Your using two? Total waste of battery and $! 1 would be way more than enough power for a revo and will totally overpower the HD spring with just 1. Most people (if not all) upgrade to a single strong servo to ditch the dual servo's fighting each other. This helps to save battery and removes unnecessary complexity.

I have a single 985MG in mine and it can overpower the HD servo spring, 172oz @ 6V. I run that servo for both steering and t/b.

Why did you go so high on the servos? I'd take one back and buy something else with the $120. What are you using for t/b duties?

Thanks, that's what I figured now reading the specs. I think I might take one out and put it in the other revo. It's really just a waste of power is it not? Would there be any advantage?

I have a bad habit of "over doing" it. :\

---------- Post added at 5:04 PM ---------- Previous post was at 4:56 PM ----------

I put a HS-7965MG (T/B) in it this afternoon. In our family we have 6 Revo's, so I'll have a place to put the 2nd TG.

Way overdoing it. Good servo though... will probably outlast your revos! lol

If I had to guess, the HD servo spring can be overcome with a decent 160+ oz servo. My 985MG will overcome it if I hold the wheels straight and turn the wheel on the remote. It strains to do so, but it will. Which means, a single 333oz servo will do it without breaking a sweat.

I'm also using a plastic/stock steering pivot. I just cut the arm off the other side with my dremel so it would get hung up on things. Proline used to make a single arm alloy one, but mine has held up fine for me as it is.

Found a link to one, seems hard to find now... maybe proline quit making it:
http://www.hobbyfever.com/product_info.php?products_id=4154

As for your t/b servo... I'd have went with a stronger one. I tried running weaker ones and they just die due to heavy braking. So, I gave up and bought a second 985MG. I like using those anyway since they are sealed with o-rings on the case, screws and output shaft. It will endo my revo all day long if I don't have my EPA's set right. The speed of a servo for t/b isn't nearly as important on a MT as it is in onroad. For me, I like durable. But at .13sec, the 985 isn't a slouch in that regard either.

olds97_lss said:

Way overdoing it. Good servo though... will probably outlast your revos! lol

If I had to guess, the HD servo spring can be overcome with a decent 160+ oz servo. My 985MG will overcome it if I hold the wheels straight and turn the wheel on the remote. It strains to do so, but it will. Which means, a single 333oz servo will do it without breaking a sweat.

I'm also using a plastic/stock steering pivot. I just cut the arm off the other side with my dremel so it would get hung up on things. Proline used to make a single arm alloy one, but mine has held up fine for me as it is.

Found a link to one, seems hard to find now... maybe proline quit making it:
http://www.hobbyfever.com/product_info.php?products_id=4154

As for your t/b servo... I'd have went with a stronger one. I tried running weaker ones and they just die due to heavy braking. So, I gave up and bought a second 985MG. I like using those anyway since they are sealed with o-rings on the case, screws and output shaft. It will endo my revo all day long if I don't have my EPA's set right.

Click to expand...

I hav e 6 of those I picked from a bin from an RC shop that went broke. paid about $6.00 for all, lol. If you ever need one just pm me and I can send it.

---------- Post added at 5:27 PM ---------- Previous post was at 5:24 PM ----------

Would the 9755TG be any good for the T/B?

Guessing you meant 7955TG? If so, then yes, but again, still overkill. Not as fast as what I'm running, but really, not sure .02 seconds would even be noticeable. lol

The 7965MG has 111 oz./inch at 4.8V. That shouldnt be underpowered should it?

I also have a new spare HS-7975HB, that might be a better option with 119 oz/in at 4.8V and 0.13 sec.

What do you think?

I'm not saying either won't work, just saying what I generally proffer and have good results with. Out of those two, the 7975 is a stronger/faster servo, so I would go with it.

I'm assuming your using a rechargeable 6V pack as well.

Just whatever battery is stock, why do you ask?

I was looking to upgrade but still debating on keeping my reverse.

Then it's a 6V pack and that's the numbers you look at on the servos.

Okay, Thanks. It's probably very obvious this is new to me and I'm a bit of a dummy, lol. I really appreciate your help.

No problem. It will all eventually make sense.

I AM RUNNING THE Hi TEC SERVO HS-645MG IN THE THROTTLE/BRAKE
I ONLY RUN 1 STEERING SERVO ALSO,YOU ONLY REALLY NEED ONE NICE STEERING SERVO/ I HAVE THE AIRTRONICS (94357) THESE ARE 180.00 SERVO,BUT NO I DID NOT PAY FULL PRICE. PICKED TWO UP NEW IN ORIGANAL BOX FOR 50.00$ I HAVE THIS OTHER AIRTRONICS SERVO ALSO STILL NEW IN BOX. I WAS GOING TO USE THIS BUT NOT SURE IF ITS BETTER THAN WHAT USING NOW
94358Z 4.8V@160 OZ/IN SPEED .13
6.0V@200 OZ/IN SPEED .10 IF SOMEONE THINKS I SHOULD BE USING THIS ONE INSTEAD OF THE AIR94357Z LET ME KNOW WHAT YOU MAY THINK,THANKS.

DUDE, WHY THE CAPS?^

With an aluminum arm you could easily get away with one of those suckers. That's what I would do anyway, because two servos can take a toll on each other over time.

Yes, I removed one last night and installed the proline arm. It works great. Actually allot simpler as well.

I also installed the HS-7975HB for the T/B. There is without a doubt, much more responsiveness.

Thanks guys

Here is a Servo Arm just about identical to the old proline arms.

http://www.amainhobbies.com/product_info.php/cPath/1_25_1466_74/products_id/21504/n/GH-Racing-Aluminum-Servo-Arm-Blue-Traxxas-Revo
$13.49