Pinion/spur mesh too noisy?

[skybolt]

Anyone else think their rig is noisier than it should be?

I have changed pinion brand and tooth count, a new spur, played with tightening/loosening the gear cover screws but cant seem to get a "quiet" mesh. I honestly don't care for all these "here, let me do the thinking for you" advancements in everyday life, but that's for another thread.....

[Dbx]

Pinion noise is one of my pet hates.
I’m still on a mission to make my rigs quieter, but have found some useful methods. This is on SCX10 / Wraith and TH. Not sure how TRX4 compares.
Xtraspeed do a delrin helical spur with steel pinion setup. This is much quieter than any straight cut gear that I’ve used.
I have chewed a couple of these up. They are a fairly fine pitch (64dp ish).
I’m now running special engineering grade, machine cut helical gears on a mod 0.7 pitch. These are super quiet and very tough. I have to modify them specially on a lathe, but it’s worth it for the quiet running.

[Teng]

I used mountain bike dry chain lube to reduce the noises and they are very effective thought.

[HumboldtEF]

If your a bit on the brave/tinkerer side you could try to connect the adjustment holes to give a much wider adjustment slot. That may work out better on an aftermarket alloy replacement, or if you use the stock mount just use some washers to spread the load and ensure they stay put.

My mesh has stayed good in the hole I've been using, I have swapped motors a few times but haven't had any issues with mesh.

Originally Posted by Teng

I used mountain bike dry chain lube to reduce the noises and they are very effective thought.

Interesting, Has that dry lube ever worked its way into the slipper clutch? and is that like graphite based or what? it seems like theres a lot to choose from.

EDIT: nevermind, it looks like most are either Teflon or wax based.

[skybolt]

I too am ocd about noises, I’ve had pretty much everyone I crawl with comment on how quite my rigs are, until the TRX4 that is...
I’m not a big fan of how the motor “hangs” off trans the transmission, I almost feel that the noise is from the two gears not being on the same plane (not sure what you call it) I think the big ole Titan sags causing an odd mesh.


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[Inspector86]

I have two TRX4s. One is very noisy and one is very quiet. Both have been changed to 9 tooth pinion gears. I had a wheel get bound up in a rock and smoked the slipper clutch on the noisy rig. I think when I replaced the slipper clutch I reinstalled the spur gear 180deg out and that is when it started being noisy. I was hoping it would quiet down but that does not seem to be happening after a half dozen battery packs. I tried some powdered graphite and that helped but was not a complete fix.

[AggressorBLUE]

Originally Posted by skybolt

I too am ocd about noises, I’ve had pretty much everyone I crawl with comment on how quite my rigs are, until the TRX4 that is...
I’m not a big fan of how the motor “hangs” off trans the transmission, I almost feel that the noise is from the two gears not being on the same plane (not sure what you call it) I think the big ole Titan sags causing an odd mesh.


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Yeah, as I commented in another thread, we need an aftermarket replacement for the upper and lower gear cover/motor mount holder with AU parts. I'd also love if the lower had a recess for a lock nut. the combination of weight of the motor, plus screwing into plastic parts, means you really can't tighten down the mount enough.

[Tommy23490]

i bought the aluminum motor mount and put a little bit bigger screws in the hold down bracket and just kept adjusting the the hole placement until it got better. Seemed to work for me..

[skybolt]

Originally Posted by Tommy23490

i bought the aluminum motor mount and put a little bit bigger screws in the hold down bracket and just kept adjusting the the hole placement until it got better. Seemed to work for me..

Aluminum motor mount?
I guess I need to look a little harder next time, I hadn’t found one yet


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[AggressorBLUE]

I think he's referring to something like this from hot racing:
TRXF1801

Which is a replacement for the motor mount part 8290.

HR does also offer an AU version of gear cover part of 8290 as well.

They also offer part 8291 (the trans housing) in AU.

But what we REALLY need is part 8238 in metal, as the that's what the spur gear cover screws bolt into, and what the motor mount rests in. It's an easily over-looked, but critical part that marries the trans to the motor and spur gear, as well as cross braces the frame and mounts one of the links for the front axle and protects the output shaft for the front axle and on top of all that is one of the first parts of the trucks underside to be exposed to scraping rocks on break over.

But yeah, sure, every-after-market-rc-part-maker-ever-and-my-grandma, you're right, what we all really need is yet another set of brass porta weights.

https://traxxas.com/explodedviews/TR...ssion-Assembly

[HumboldtEF]

You can stick a strip of electric tape in the grove of the motor mount to help tighten it up, without it there is a little slop.
Thread here

[5150WS6]

I too have been driven crazy with that whine noise from the pinion/spur. I found out though, it's the angle of the pinion and spur. If you take out the motor completely and roll the chassis, it's silent. Add the motor/pinion back in and you get the noise. But if you tip the rear of the motor up just a hair, making the gear meshing slightly tighter, that sound also goes away. Or at least 85% of it does. It's just sloppy tolerances in my book.



I did the tape trick on the top of the motor cover and it seems to do the trick to keep everything a little tighter.

[Bburak]

Or maybe the solution is to use a belt drive?
RC4WD offers a dedicated item.
Please see https://store.rc4wd.com/vvv-c1380.html

[TacoCrawler]

I've little issue using 48 pitch gearing (for crawlers) as long as I run a cover and don't leave the gears exposed.
You got to be sure your mesh is set right tho' and that your motor screws don't back off on a hit.

I personally do not like the sound of meshing 32 pitch gears. Might think differently using helical cut 32 pitch gears.
But I'll doubt it.

Maybe 32 pitch gears are are presumed to be stronger then 48 pitch gears, because they have a larger tooth / mesh.
But that it is really not true. As the tolerances will allow for more contaminants to get in the teeth before it fails.
So if your going to run your spur gear uncovered then I would suggest sticking with 32P gears externally.

If your 48P gear mesh is set correctly and it stays put. They will be quieter and strong enough for most everything.
After all many internal (set) gears are 48 pitch as well.
A shorter tooth will be stronger then a taller tooth every time.

Generally stripped gearing occurs when the motor moves from a hard hit and changes the spur gear mesh.
I use a little Loctite applied to the threads of my motor screws to ensure they stay tight.
If it's geared correctly if won't become hot enough to loosen the motor's screws.

I set my 48P spur gear / pinion mesh using a sheet thickness of rule paper.

[ferp420]

I've striped so many sets of 48p gears both internal and external with the cover on and off

I prefer a 32p plastic spur and a hardened steal pinion gear

[TacoCrawler]

Originally Posted by ferp420

I've striped so many sets of 48p gears both internal and external with the cover on and off

I prefer a 32p plastic spur and a hardened steal pinion gear

funny that you say so... but I never stripped one in nearly 20 years on multiple RC crawlers. Dang you must be rough on your toys

I'll agree with using hardened steel gears though.
Still gonna be 48P though 'cuz I hate the noise