BMAX4iii drivetrain noise
 

I've been running my BMAX4iii for a few months now and although I am generally happy with the car, I find that the drivetrain is quite noisy. Everything is running freely and the pinion/spur gear mesh is correct. The car is still quite new so there is no gear wear. I wonder if this is just an aspect of the car due to the steel ring/pinion gears and shaft-drive?

Do you run with the kit shims on the outdrives to space the ring and pinion gears? The mesh seems fine to me with the kit shims.

I lightly lube the gearboxes with a SMALL amount of Associated black grease.

Any views?

Comes from the bearings for the spur moving about. Underneath the plate that holds them down, use something soft to pad them slightly. I just use double sided tape but don't take the backing off the side facing the bearing and this stops the noise.

The slipper assembly bearings move within the central mounts. The noise is the slipper unit moving as the motor spools up and down.
You need to remove the top plate, place two small squares of double sided tape on each side where the bearings meet it. Screw the plate back down, which compresses the tape against the bearing outer race.
This seats the slipper unit correctly taking up any play, and removing the source of your noise. You may have to replace the spur gear for a silent transmission, as the movement does cause wear to the slipper.

looks like Allan beat me to it.

Yep had the same issue, very thin piece of double sided tape sorted it . Only peeling one side .

Mines silent, at least, the noise from my ESC fan makes me believe that lol, nice tip though guys, ill do that too, then get a new fan!
Or, i could sell somebody my fan, no need to add weight with tape and your tranny will whisper along lol!

Lee

Thanks guys, just what I needed to know.

Mine sounds particularly agricultural. I did narrow it down to the center but haven't bothered to do anything with it as it seemed OK. Just sounded like a tractor. I'll add some tape as suggested. Cheers!

Be careful if the tape is too thick it'll damage the bearings, I found electrician's tape was perfect.

I've used double sided tape but noise has crept up over time again.. Don't notice it as much on a larger outdoor track.

Did you use a doubled sided cello tape or the double sided tape used to mount the esc etc?

I've used some double-sided foam tape which I use to mount the receiver/esc. It compresses easily so should just absorb any vibration. Will run it for the 1st time with this at the 4WD East Mids regional tomorrow so will report back after that.

It doesn't want to be tight when placing the top back on .

I don't understand why. My tape is about 5 times thicker than that. Due to it being soft the bearings have just made indentations in the tape.

The foam tape I used worked perfectly - yesterday my drivetrain was noticeably quieter than before. Thanks all. :)

Mine only needed thin tape , guess it will vary as some cars won't need any .

Cool. Glad its sorted.

Yeah same here. I used adhesive foam and it was spot on.