This is Trixie. She eats pinion gears.

[KennethMiller19]

So, before I go on, yes, I name my rc cars. Yes, they deserve to have names. Yes, I may be crazy.

But anyway. I've had my 2wd rustler for quite a while, and love her to death. She's a solid off-road basher, but I've come across an issue recently.

Trixie started off as an XL-5 that I switch to the VXL 3s system. At the same time I did that, I changed up her gearing. I went from the stock gearing to a 19/86 combo with a steel spur. On 2s, she's great and really moves across gravel and hard pack. On 3s, she gets hungry and chows down on my pinion gears. She's eaten 3 19 tooth pinions in the last three weeks.

I know part of my problem is likely the steel spur gear. I've checked and rechecked the gear mesh to make sure it's right, and it seems ok.

Is this a decent gear combo or did I totally screw up? Will swapping the spur for a softer plastic one make a difference, or will it just start eating the spur instead of the pinion? Anyone have suggestions for a gear combo for off-road bashing? Id like to not sacrifice all of my speed, but a little bit of loss wouldn't hurt too much, I guess....

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[Panther6834]

You've started that the spur is steel (hardened steel, I'm assuming), but you didn't indicate the material of the pinion.


~ More peace, love, and kindness would make the world a much better place

[KennethMiller19]

You've started that the spur is steel (hardened steel, I'm assuming), but you didn't indicate the material of the pinion.


~ More peace, love, and kindness would make the world a much better place

The first gear that got eaten was (I think) a Traxxas gear (steel?) And the second pinion that got eaten was one I bought on amazon, and it wasn't stated what material they were. I'm willing to believe they were sub-par gears, as it was a pack of various sizes from a brand I'd never heard of for a price that was too good to pass up. The third one was a Traxxas pinion, though I'm not 100% sure what material it was. I'm assuming steel, but I'll have to look at the package and see if it's listed there. It wasn't in the product description from the site I ordered from (I checked), so I won't know for sure until I get home.

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[Panther6834]

If the spur is hardened steel, you have to use a pinion also made of hardened steel...anything less, incl standard Steel, and the spur will chew it up, exactly as your experiencing.


~ More peace, love, and kindness would make the world a much better place

[fortunespoonz]

Ive seen a lot of people struggle with stripped gears after making changes. Meshing can be tricky.
I’ve never run a metal spur, but I bet getting the mesh right is even more important.
If you didn’t have a metal spur, we’d probably be discussing you stripped plastic spur instead.
The weakest point will give. In this case it’s the pinion.
19/86 isn’t crazy gearing withe those tires. Something else is up.
I would check the bearings on the top shaft and motor.
Any excess play can cause gears to go faster.
Lastly, are you lubing the gears at all?

[KennethMiller19]

Ive seen a lot of people struggle with stripped gears after making changes. Meshing can be tricky.
I’ve never run a metal spur, but I bet getting the mesh right is even more important.
If you didn’t have a metal spur, we’d probably be discussing you stripped plastic spur instead.
The weakest point will give. In this case it’s the pinion.
19/86 isn’t crazy gearing withe those tires. Something else is up.
I would check the bearings on the top shaft and motor.
Any excess play can cause gears to go faster.
Lastly, are you lubing the gears at all?

I have noticed that the screws holding my motor in it's mount are constantly getting loose, so I kind of wonder if the motor is vibrating loose and mashing my gears together.... Anyone know if I can put Loctite on those screws or will it mess up my motor?

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[Panther6834]

Rule of thumb:. Always use Loctite when screwing metal into metal.


~ More peace, love, and kindness would make the world a much better place

[KennethMiller19]

Rule of thumb:. Always use Loctite when screwing metal into metal.


~ More peace, love, and kindness would make the world a much better place

Those are probably the only two screws on the entire rustler that DONT have blue Loctite on them. I love that stuff....

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[KennethMiller19]

The 19t pinion gears I have are Traxxas part #2419. I can't find anything that says what material they are.

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[fortunespoonz]

They are steel but not “hardened”.

[KennethMiller19]

They are steel but not “hardened”.

Hmm. May have to do a little shopping and see if I can find a hardened one in the right size, then. That may be part of the problem. Gonna try getting the motor mount screws tightened up this weekend and see if that helps anything.

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[Acidic01]

If motor is moving that is a major part of the problem. Perhaps loctite and or a spring or other anti backout washer as well. I always have a washer on my motor screws, as gives more surface area on diff housing. I don't loctite them but also no issues.


Second is having your slipper clutch adjusted right. You want some slip. I put car against my leg and start tightening slipper till it starts to climb up my leg but I can also heat it slip.


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[KennethMiller19]

If motor is moving that is a major part of the problem. Perhaps loctite and or a spring or other anti backout washer as well. I always have a washer on my motor screws, as gives more surface area on diff housing. I don't loctite them but also no issues.


Second is having your slipper clutch adjusted right. You want some slip. I put car against my leg and start tightening slipper till it starts to climb up my leg but I can also heat it slip.


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I've got the slipper set pretty good; never had any issues with it. I'll tinker with it this weekend and see if I can track down the problem. I think it's the motor mounts vibrating loose, but not completely sure. Thanks for the tip!!

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[RC Dad]

I've got the slipper set pretty good; never had any issues with it. I'll tinker with it this weekend and see if I can track down the problem. I think it's the motor mounts vibrating loose, but not completely sure. Thanks for the tip!!

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If you’re not too married to the idea of a steel spur, I’d say go with a plastic one. It’s nice to have a sacrificial lamb in the drivetrain, and that’s about the easiest part to replace.


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[KennethMiller19]

If you’re not too married to the idea of a steel spur, I’d say go with a plastic one. It’s nice to have a sacrificial lamb in the drivetrain, and that’s about the easiest part to replace.


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I have several different sizes of plastic spurs, so I'll have to see if I have one that's the right size. At least it's so far just $5 pinion gears instead of something more expensive.

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[Chubaka407]

I have several different sizes of plastic spurs, so I'll have to see if I have one that's the right size. At least it's so far just $5 pinion gears instead of something more expensive.

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Look into the 32p mod. Revo and jato type 3 screw mount plastic spurs with bigger teeth. Combine that with a robinson racing pinion and your set. If you do this you will need a spur and pinion and will need to calculate your cutrent ratio.

If the pinion sticks to a magnet it is steel. If not its probably aluminum. If it doesnt stick and is heavy it could be brass. Pinions I use are steel or hardened steel. On my mini I actually heat the ring and pinions cherry red then dip them 2 or 3x to harden them. I never done a pinion.

[TwoBelugas]

Robinson racing makes some darn fine hardened steel pinions.

[Panther6834]

Robinson racing makes some darn fine hardened steel pinions.

Got that right, kemosabe. The best I can remember, all of my (land) vehicles are running RR pinions. For the R4sty I installed (ok...and removed, having had to ship it to Castle, due to ESC & motor defects) a 1/8 motor in, I had initially purchased some Arrma 'D' pinions...but, due to some manufacturing error (they were only 4.94mm diameter, which, obviously, won't fit a 5mm shaft, as they're designed to fit), I returned them to Amain, and picked up RR replacements.


~ More peace, love, and kindness would make the world a much better place

[Acidic01]

Another idea is are your pinion and spur the same pitch of teeth? If not this could also cause issues.

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[Panther6834]

Another idea is are your pinion and spur the same pitch of teeth? If not this could also cause issues.

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Now, that's something I hadn't thought of...and, quite true. Even mixing 32p & 0.8Mod can potentially cause an eventual problem, as those two are NOT the same. Many people think they're identically. They are very close...but, again, NOT 'identical'. Definitely worth it for the Op to check.


~ More peace, love, and kindness would make the world a much better place

[KennethMiller19]

Another idea is are your pinion and spur the same pitch of teeth? If not this could also cause issues.

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Yeppers, they are both 48 pitch.

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[KennethMiller19]

Okay, so I thought I had everything figured out. I swapped the steel pinion for a plastic one that's the same size and pitch (86t/48p), put some Loctite on the motor mounts and tightened them up, set the mesh and took it for a spin. Ran probably half of a 3s battery with no problems. She was humming along like a champ. All of a sudden, I get a loud squeal and she stops. Spur and pinion are still intact, no damage. When I pick the back end up and hit the throttle, everything seems ok. The minute she hits the ground, I get a high pitched squeal. Rechecked the mesh, and same thing. Pinion intact, spur intact as well. Any ideas? Posting a short video clip, so if anyone can diagnose the problem, I'd really appreciate it.http://cloud.tapatalk.com/s/60318646..._135340649.mp4

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[Panther6834]

No, NOT plastic pinion...and, NEVER Loctite plastic. Use steel pinion & plastic spur. Putting Loctite on the plastic probably softened it up.


~ More peace, love, and kindness would make the world a much better place

[KennethMiller19]

No, NOT plastic pinion...and, NEVER Loctite plastic. Use steel pinion & plastic spur. Putting Loctite on the plastic probably softened it up.


~ More peace, love, and kindness would make the world a much better place

Did I say pinion? I meant spur. It's a plastic spur and steel pinion. My bad. And I didn't put Loctite on the plastic, just on the mounting screws holding the motor in place. Sorry, I typed that post really fast and didn't check it over before I posted it.

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[Squeegie]

Can’t open and view your video. Is your slipper slipping? May need to take it apart and check for glazing. May need to scuff it up and reset it.

Good luck!

[KennethMiller19]

Can’t open and view your video. Is your slipper slipping? May need to take it apart and check for glazing. May need to scuff it up and reset it.

Good luck!

I checked it when I swapped out the spur, but it may be worth another look. It's a fairly new HR clutch, but that doesn't mean there isn't something off kilter with it. I'll try to repost the video clip.

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[KennethMiller19]

Try this againhttp://cloud.tapatalk.com/s/6031a399..._135340649.mp4

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[KennethMiller19]

Okay, workaround for the video. Doesn't sound as bad in the video as it does first hand...

https://youtu.be/WugEnPRjdHI

https://youtu.be/iUFlWmuwYZY

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[Acidic01]

Perhaps pull spur and run motor not connected to anything perhaps motor bearing. Or another bearing in diff going out. U also seem to have a lot of slop in your wheels.

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[Chubaka407]

One of the three gears in the tranny more than likely. If it is and the bearings are still good, probabl shortened the life with the steel spur.

The slop in the wheels can be bearings as mentioned. Also my plastic rear stub holder gets the screwhole sloppy and creates that. A simple locknut on the other can fix it if thats the cause

[KennethMiller19]

One of the three gears in the tranny more than likely. If it is and the bearings are still good, probabl shortened the life with the steel spur.

The slop in the wheels can be bearings as mentioned. Also my plastic rear stub holder gets the screwhole sloppy and creates that. A simple locknut on the other can fix it if thats the cause

Yeah, I'm working in the wheel slop. She's been run really hard over the last year, so she's kinda beat up. It's my "Let's go way too fast and do stupid stuff" car. The steering just needs to be dialed in again and tightened up. I went thru most of the steering components a couple weeks ago, but got distracted by the pinion gear issue. It was my first rc car, so she definetly has some scars.

I was kinda wondering if it could be something in the diff. The motor hums nicely when it's not hooked to the trans, and she sounds ok when her back end is up off the ground, but starts squealing as soon as the wheels touch the ground.

It's been a long time since I pulled the trans and diff apart and cleaned it up, so it may be worth cracking it open and checking everything.

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[KennethMiller19]

Just an update:. I pulled the diff apart yesterday and cleaned it up. None of the gears seemed damaged, but I did find a bearing that was worn pretty badly. The seal on one side was worn down to the point you could see metal thru it, and it didn't turn as efficiently as the other bearings I pulled out. I'm thinking that may have been a major contributing factor to my problems, if not the whole problem entirely. I didn't get to put everything back together, and I need to pick up some grease before I reassemble the gearbox. Probably be a project for this weekend, but I may get a start on it after work sometime this week.

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[KennethMiller19]

Still having problems. Got the trans and diff cleaned up and checked, put some fresh grease in both and put everything back together. Took it for a test run with the same problems. I swapped back to my steel spur gear, and managed to get it to about half throttle before it started squealing again. Pinion wasn't damaged, and the mesh was good. Its like when I give it throttle, something locks up and it looses momentum. I checked the wheel bearings and they're old, but not shot.



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[KennethMiller19]

Figured it out. The plastic plate in the motor mount was warped, and wasn't allowing the gears to mesh correctly. When I'd hit a hard bump, it would shift and throw my mesh out of line. Took it out and everything runs perfectly. Have to get a replacement for it.

All this time and work, and it turns out to be a $2 part, lol. Thanks to everyone for the help and suggestions. Also, whoever it was who suggested putting a lock nut on the back of the camber link screw where it mounts to the rear carriers, thanks for that suggestion. My back wheels aren't going in twelve different directions anymore, and she keeps a line a lot better. Back end isn't vibrating as bad either.

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