More Questions....

[R-N-R]

I adjusted the motor to be tight with the spur gear with a piece of paper between them. Is this correct?

How tight should the slipper tension spring be?

The stock spur gear had every other hole filled with friction pegs.
The replacement set that I purchased had enough for every hole. Which is correct?

What is the purpose / function of the servo saver?
I know that it saves the servo gears, but how does it work?
Flipping the truck, or even a mild bump into the front wheel seems to require a "re-centering" adjustment (new servo). However, perhaps....(see below) Is this normal? My stock setup did not do this, but then I stripped the gears out of that one.

I just replaced my stock servo with a $14 Hobbico replacement that is supposedly the same as the Traxxes stock servo. Meaning that I was told that Hobbico manufacters most of the servos including units sold under the Traxxax, Fubico, etc... labels.
I'm not so sure that this was a good deal though. The servo seems to "lose" and "recover" it's center position. This naturally makes driving really interesting. Has anybodu else experienced this? Is this most likely a defective unit? Or perhaps simply a case of "el-cheapo" parts?



TIA,
Bill

[Tazz R/C owner]

I adjusted the motor to be tight with the spur gear with a piece of paper between them. Is this correct?
Yes; a paper's thickness is all the play you need between the gears.

How tight should the slipper tension spring be?
I like to torque the spring tight then back it off betweem ½ and 1 turn.

The stock spur gear had every other hole filled with friction pegs.
The replacement set that I purchased had enough for every hole. Which is correct?
Really, both are right. As long as it's balanced it will be fine.

What is the purpose / function of the servo saver?
I know that it saves the servo gears, but how does it work?
The servo saver is made from a couple pieces of plastic which encase a spring. If the wheels suddenly get bumped, the outter half of the servo saver will turn and compress the spring, while the inner half (connected to servo) will hardly turn at all.


Your servo problem may be related to just having a cheap servo, but it's more likely that you are using the wrong servo saver adapter in your servo.
Airtronics and JR servos have 23 splines on their outpt gear shaft.
Hitec and Hobbico servos have 24 splines on their output gear shaft.
Futaba, Traxxas, and Cirrus servos have 25 splines on their output gear shafts.
Although it may not seem like it, that one spline makes all the difference; it would be like trying to get a 48pitch gear to mesh with a 64pitch gear; it's just not going to happen.
If you have a plastic geared servo, you will probably have to replace the gears and the servo saver (get something by Kimbrough).
If it's a metal geared servo, you should only have to replace the servo saver.

[nwilcox]

Your servo problem may be related to just having a cheap servo, but it's more likely that you are using the wrong servo saver adapter in your servo. Airtronics and JR servos have 23 splines on their outpt gear shaft. Hitec and Hobbico servos have 24 splines on their output gear shaft. Futaba, Traxxas, and Cirrus servos have 25 splines on their output gear shafts.
Although it may not seem like it, that one spline makes all the difference; it would be like trying to get a 48pitch gear to mesh with a 64pitch gear; it's just not going to happen. If you have a plastic geared servo, you will probably have to replace the gears and the servo saver (get something by Kimbrough). If it's a metal geared servo, you should only have to replace the servo saver.

I see your point, but I think he was told that this servo was the replacement servo. You mentioned replacing the gears. What is the best way to replace the metal gear on the send of the servo motor without screwing up the contacts, it is a plastic geared servo?

[R-N-R]

My spur gear "wobbles". How do I balance it?

The servos and servo savers do not list the spline count on the package. How do I ensure that I get the correct combination.
My LHS tells me that the Hobbico CS-60 is a direct replacement for the stock Traxxas (made by Hobbico???). However if the Traxxas has 25 splines on the servo save and the Hobbico has 24 splines on it's output gear then I understand why the wheels jump off center at minor impact.

What is the "correct" procedure for initially setting the servo?

I replaced my (new) defective (?) servo today because it seemed to be "losing" it's center position. This occurred while driving and upon power up.

My LHS asked if I initially centered it correctly. I told them that I removed the servo saver, then powered up the servo, then installed the saver with the wheels in the straight forward position. My LHS told me that this was "sort of correct".

The servo is a Hobbico HCAM0149, CS-60 Standard Sport Servo. This is not listed on their web site, but it seems comparable to the CS-61.

[Tazz R/C owner]

My spur gear "wobbles". How do I balance it?
It's going to wobble, there esn't much you can do other than buying larger slipper plates (the RRP slipper set). It's not a problem though; as the spur spins faster, it actually straightens out.

The servos and servo savers do not list the spline count on the package. How do I ensure that I get the correct combination.
My LHS tells me that the Hobbico CS-60 is a direct replacement for the stock Traxxas (made by Hobbico???). However if the Traxxas has 25 splines on the servo save and the Hobbico has 24 splines on it's output gear then I understand why the wheels jump off center at minor impact.
I stated earlier the number of splines, you can count them if you want. What your LHS ment to say, is that the size of the servo and the plug will work in place of your stock servo.

What is the "correct" procedure for initially setting the servo?
My LHS asked if I initially centered it correctly. I told them that I removed the servo saver, then powered up the servo, then installed the saver with the wheels in the straight forward position. My LHS told me that this was "sort of correct".
I'll let Traxxas answer that: click here.
You need to make sure the bellcranks are centered, too. If the turnbuckle linking the servo saver to the bellcrank is too long or short, you will need to do some wierd things to the toe turnbuckles to get the tires straight.

[R-N-R]

Thanks again Tazz!

I'll certainly take you word for it on the spline gear counts
I've done alot of reading since my post and I now understand better how the servos and savers are sold.

I think that centering the servo is pretty straight forward and that I have performed the process as directed.

I cannot seem to locate the bellcranks on my Sport SE, in the parts list, or on the drawings. I must be missing the boat here. I see them listed on Towers WEB site, but no reference to the Sport model, only the Rustler, T-Maxx, etc.... Can you point me in the right direction?

It sure seems like I would have saved myself alot of BS if I had just replace the 2018 with Hitec/Kimbrough combination. btw, I did not use an adapter with the Hobbico servo.

Bill

Travis, Did your parents hang R/C cars from the mobile over your crib by any chance. Geeze you know an aweful lot about these for being such a young man (comparatively speaking of course). btw, nice web site!!

[R-N-R]

hhmmm, I think I recall plugging in my servo backwards at one point..... Perhaps I need a new servo and receiver

[Tazz R/C owner]

I cannot seem to locate the bellcranks on my Sport SE, in the parts list, or on the drawings. I must be missing the boat here. I see them listed on Towers WEB site, but no reference to the Sport model, only the Rustler, T-Maxx, etc.... Can you point me in the right direction?
D'oh! I forget what forum I am in sometimes; the Nitro Sport does not have bellcranks.
What you need to do is make sure the front edge of the servo saver is perpendicular to the rest of the chassis.


hhmmm, I think I recall plugging in my servo backwards at one point..... Perhaps I need a new servo and receiver
That could cause some problems, possibly to the receiver and the servo. Just do a quick check by plugging in the throttle servo into the steering servo position and see if the problem still occurs (you don't need to drive the truck, just check the position of the carb). If you still see big differences in the centering position you may need to replace the receiver. If it's in relatively the same position, it'll be fine, just replace the steering servo.
For a cheap plastic geared servo, the 475hb is pretty good.
http://www.servocity.com/ServoCity/P...er_pro_bb.html



I first got into RC when I was four. It was just toy electrics, but less than a year later, I started with hobby class rc - I broke most of my toy so she bought me a Tamiya buggy. I had it for a few years, then we had a fire. I didn't get back into RC until five years ago with my Nitro Rustler.
Thanks for the compliments on my website.
I will be learning a couple more scripting languages this and next year, so I hope to make it even better.

[R-N-R]

I swapped out the Hobbico for a new one at my LHS. Oddly enough, the Hobbico looks exactly like the HS-475HB right down to the mounting hardware and horns that are included. I also replaced the servo saver, it is a much tighter fit to the servo now. I think that the stock saver was slightly stripped or atleast the teeth were a bit rounded. Unfortunately, I also had to replace the receiver to correct the centering problem.