Why so loud?

[JeepinDoug]

Doesn't seem to matter where I mesh the spur/pinion, loose or close the damn thing is loud.
So I started working on where all the noise is coming.
Trimmed the throttle forward until it spun really slow, it turned and stopped. Tapped the throttle again and it turned slow and stopped, in the same spot.

I checked the spur with a jeweler's loop to see if it had anything wedged in the gear but nothing.

I know these spurs are injection molded so they tend to spin eccentric, that's why a few companies make some nice machined delrin spurs. I've never seen machined delrin spurs that look like the Losi spur.

Does anyone know if there are quality spurs made for these? Possibly a spur adapter for another pitch to run on this output style?
Anyway to avoid all the noise this thing makes?

[Gatekeeper]

I took the trans apart and greased the gears and it helped alot but yes they do make some noise

[dpdsurf]

Are you certain it's only the tranny area Doug? Seams to me like most the noise comes from the axles???

[Shadill]

I also was wondering why its so loud, especially when your trying to crawl in the house with someone asleep

[JeepinDoug]

I had a whole area of problems which are fixed now but to answer your question yes. In particular not the transmission internals, that's just a typical straight cut gear noise.
The loud noise is all from the spur and pinion.

********
The original problem started crawling Friday afternoon. The motor was puffing smoke and very sluggish.
Pulled the motor, broke it down to check everything, (HH mini torq master). The windings were a shade darker than I expected but intact. I polished the com, replaced the brushes and did the 5 minute break-in with D-cell in water.
Cleaned and cycled perfectly.

Since the motor didn't seem to be the culprit I checked elsewhere.
With the skid and trans out of the rig I tried to turn the driveshaft by hand........barely moved. Pulled the wheels and it move freely.
Result was every single drive hex cross pin was bent from over tightening the wheels.
New pins and wheels back on it turns freely now.
Before I put the skid and trans back in the rig I connected everything to check the motor refreshing.
So back to this topic.
*****************
Spun up the motor and the noise is annoying. The noise was the same before these problems and maybe even more annoying now when the Berg runs whisper quiet.
So I'm just trying to isolate the noise and see if I could correct it.
I lubed the trans gears when I installed the metal center diff and it did make a small change but it's still not acceptable.
You could here the frequency change thru one revolution of the spur gear as it turns and repeat as it continues.
That's the annoying part. I could see it, hear it and feel it in my hand but can't fix it without a quality spur.

Unless there's an obvious and easy fix I'll start working on a good spur adapter and thicker motor plate to help gear alignment.

[dpdsurf]

Maybe tranny parts or entire trannys from other 1:18 scale trucks would work?

[dave m]

These are annoyingly loud.

Does everyone else's MRC make a high pitch electronic sound when you press on the throttle (forward or reverse)? It's not a mechanical sound but more like a feedback signal coming form the receiver?

[JPH Racing]

Doug: Maybe it's time for an iPod to drown out the noise while you crawl?? It would do double duty, no more annoying trani noise and you wouldn't have to listen to Dpdsurfs comments while you comp! :-P

[JPH Racing]

Dave: what you're hearing is normal. Is the high frequancy beep coming from the speedcontrol and motor as you move forward. If it's too excessive, you might want to swing by a hobby shop and have them listen to it, because something could be binding that could cause issues later on.

[bent70]

you want to borrow my brushless outrunner/mm that will cover the sound.

[JeepinDoug]

That's how I fix my brakes on the car, turn the radio up..

[dave m]

Originally Posted by JPH Racing

Dave: what you're hearing is normal. Is the high frequancy beep coming from the speedcontrol and motor as you move forward. If it's too excessive, you might want to swing by a hobby shop and have them listen to it, because something could be binding that could cause issues later on.

Thats what I thought. Can it be disabled? It's more annoying than the gear clash

[JeepinDoug]

Ok, so here's my fix;

Robinson Racing 48 pitch 60t spur, Losi Mini T 15t pinion.

The center hole on the spur measures .375", the Losi's input hub measures .398"/.402".
I used letter drills to ream the center hole by hand, one letter drill at a time up to the W drill. The spur fit perfectly.
The motor/pinion adjustment slots in the motor plate needed room for more adjustment. Dremel tool the slots and put it back together.
The stock Losi has a 60t spur and 14t pinion so I'm off by one pinion tooth but I'll live.

Much, much quieter. You still get the straight cut gear noise but the terrible noise from the eccentric spur is gone.