terrible grinding sound - Page 2 - RC-Monster Forums

BrianG · 12.23.2009, 09:18 PM

Hmm, the ebay listing says it's designed for 8th scale conversions, so it should work if they're telling the truth.

Yeah, the one on the left is a CB. The right is the kind Mike used to sell a while back before he started selling his hardened steel version shaped a little more like a CB.

Easy way to tell if your gear is ok is to roll it across a spur with the pinion not mounted. It should roll smooth without catching. If it catches, it's the wrong type. Still, a vid showing how it sounds would be helpful. I'd hate for you to go get different pinions just to find out it's something else.

suicideneil · 09:47 PM

I dont believe they have a special name as such, very much depends where you buy them usually- I know Mikes pinions are super smooth with both metal and plastic spurs. Another thing worth noting is that unless the pinions are hardened steel, they will wear down very rapidly against the hardend steel spurs that are standard on most nitros.

The difference between the 2 pinions shown is the pressure angle I think, BrianG?

BrianG · 09:48 PM

Yeah, IIRC, it was the pressure angle. There was a discussion about this a while back where Mike commented at length. I'll try to find it...

Edit: Found it! http://rc-monster.com/forum/showthread.php?t=4383

ReV:-O · 12.23.2009, 10:02 PM

its strange, when i move the pinion over the spur by hand its smooth as butter, but when i attach it to the motor its crazyness.

i'll try and make a vid tomorrow
or at least some pictures

scarletboa · 12.23.2009, 10:10 PM

maybe it's the motor's "notchiness" you are hearing. is it quieter when you are driving the truck at 5-10mph?

ReV:-O · 12.23.2009, 10:14 PM

well the MMM combo is a decent combo but at slow speeds it does tend to cog. but the grinding noise has nothing to do with the electronics, that i'm sure of

What's_nitro? · 12.23.2009, 10:21 PM

Quote:

Originally Posted by scarletboa

Maybe it's the motor's "notchiness" you are hearing. Is it quieter when you are driving the truck at 5-10mph?

^ +1

Or just set it on the ground and give it a hard shove away from you. If the "grinding" noise goes away but you still hear the gears, and then comes back when the car slows down, then that's it. It's normal for motors with slotted stators to make this noise.

suicideneil · 12.23.2009, 10:28 PM

A decent macro photo of the spur and pinion together ( side and front angles) is always handy.

ReV:-O · 12.23.2009, 10:29 PM

nah i'm telling you for sure its nothing to do with the motor. i'll try and make a vid tomoz

ReV:-O · 12.24.2009, 09:41 AM

it looks like the RCM pinion also has a flat bit at the top?

http://www.rc-monster.com/proddetail...1pinion&cat=40

ReV:-O · 12.24.2009, 10:40 AM

ok i've taken some pictures and a video.
im not sure if the video works, it was taken with my phone which isnt that good.

http://www.youtube.com/watch?v=nmGkZ...layer_embedded

suicideneil · 12.24.2009, 12:46 PM

I had to download the video with youtube downloader to get it to play, but it did eventually work; dear God, what a racket!

The mesh looks pretty much fine, tiny bit looser than I run mine but perfectly acceptable, and its not skipping teeth or binding up at all either. Its just oddly loud and ratchety sounding. I thought it might be the set screw or something clanking against something else as it spins, but I'd think you'd notice that yourself.

Im stumped really, its just really really loud for some reason; only thing I can suggest is to try those other pinions when they arrive, see if they are any quiter, otherwise look into getting a plastic spur gear, that should quiten things down a bit.

Very odd...

BrianG · 12.24.2009, 01:14 PM

That is loud, but it sounds like mostly the microphone being sensitive due to lack of background noise. When the ESC arms, it gives us a little more perspective and doesn't sound quite so bad. Personally, it just sounds like a mesh that is a tad too loose and the notchiness of the motor is making the teeth slap together. You could try a different pinion to get a slight change in gear geometry, but I think you're gonna have some noise like that no matter what, maybe not quite as loud.

My 1512/2d (same kv) sounds much the same way and it has been running fine.

vader2728 · 12.24.2009, 01:48 PM

My E-Maxx with a 2200kv from a Revo sounds the same way... I've broken everything else on it, but havent stripped a spur or a pinion yet... Just an annoying price to pay...

ReV:-O · 12.24.2009, 02:39 PM

thanks for all the help guys i appreciate it.

yeah im still waiting for the other pinion to get here its taking ages, probably cos of the snow i guess.

the grinding noise is actually louder than it sounds in the video, its just bad quality recording.

i'd been running the MMM combo in my e-revo and its been fine, smooth as butter so i dont think its causing any problems.

at the moment is has a spider diff on it, and it kinda all screws together. would i have to buy an entirely new one to get a plastic spur or could i just screw one on?

also its not just noisy but theres friction as well, it takes more effort to get it rolling since its not smooth, and when in neutral it will stop quickly rather than coasting for a bit

cheers