Arrma 3S and 4S diff shims

[jondilly1974]

I don’t see any threads discussing this, so I thought it needs addressed.

The diff ring gear needs a single AR709052 - 12x15.5x0.2mm shim.

The input gear doesn’t come with a shim, but I have ordered some Kyosho 12x15mm Shim Set (10) - KYO96646 to take a little bit of slop out of mine.

Has anyone else used or needed any other shims on a 3S/4S diff?

 

[Camaroboy383]

.1 wouldn't be a bad idea either.. I have several diffs all over the place.. 1 out of 4 was nice from the rip with the .2 ring side..

1 is .1 ring side
1 is .2 cup side
1 is .2 ring side as mentioned above ( the only one with factory setup)
1 is .1 cup side..

All different..and yep, all over the place.. ? ahh the beauty of plastic production.. of course this is with the plastic yokes.. ?

 

[TimePancake]

Tbh I wouldn't know yet. I've not taken a trip inside the diffs yet, not brave enough. But you can be sure I'll be on here on a few weeks asking for help when I've gone wrong ?
I'm not surprised everyone is off a bit, 0.1mm is a pretty good tolerance for mass produced injection molded plastic.

Sometimes cheap is good ? ?

 

[Turbobrick]

I'm looking at roller bearings along with shims to try reduce slop to a min most likely SKF as there is so much slop in the stock setup imo

If you want micron slop go with a tapered bearing and shim

 

[MrTitanium]

If you want micron slop go with a tapered bearing and shim

Tapered roller bearings require a nut to give a specific load, therefore not ideal for RC applications.

 

[Turbobrick]

The load required compared to a ball screw or wheel bearing for the size of bearing is not a lot and can be applied easily enough if you have the tools prior to locking the output up but say 30nm on a 40mm screw drop that down to 8mm this pre load can be applied easily almost my hand
The angle of the bearing also is part of the issue for the preload.

Sorry to take of main topic @jondilly1974

 

[MrTitanium]

I understand its concept. Besides cost, why have we yet to see them in an RC?

 

[Turbobrick]

Yeah custom for sure locked and threaded input and drive cups with the stock grub as an extra locking tool shimmed using some sealed SKF bearings so do the trick imo

Cost and the maintenance can either be on both sides of the scale depending on the end user so it's like anything these days it's no built to last but built to be maintained with user serviceable parts.

At the end of the day that's how they make there money build it once no revenue?

 

[bicketybam]

I've never bothered messing with shims with the plastic diffs and other than killing an input gear on my K4S when I first got it, I haven't had diff issues since they came out with the BLX. I killed a few if the Mega diffs running brushless power.

 

[jondilly1974]

 

[Surchaufeur]

I don’t see any threads discussing this, so I thought it needs addressed.

The diff ring gear needs a single AR709052 - 12x15.5x0.2mm shim.

The input gear doesn’t come with a shim, but I have ordered some Kyosho 12x15mm Shim Set (10) - KYO96646 to take a little bit of slop out of mine.

Has anyone else used or needed any other shims on a 3S/4S diff?

I used 2 arrma stock shims on the metal diff yokes ring gear side
Whats the state of your sun gear im curious. I have put a coat of superglue where the second bearing sits on and the bearing fitted nice and snug

 

[jondilly1974]

I used 2 arrma stock shims on the metal diff yokes ring gear side
Whats the state of your sun gear im curious. I have put a coat of superglue where the second bearing sits on and the bearing fitted nice and snug

My sun gears always sit perfectly snug. I’ve never had side play there. With the plastic yokes, you can snug it perfectly every time. With the metal yokes, you will need shims if it is loose.

 

[MrTitanium]

I replied on youtube as follows:

Hey buddy. If I were you and wanted to get really technical, I would apply a small amount of soft clay on a portion of the crown (ring) gear, assemble everything normally and rotate the pinion by hand. Disassemble everything and the clay will tell you exactly what you need to do upon examination. This is what I do on all my diffs as it eliminates guesstimates.

 

[Surchaufeur]

My sun gears always sit perfectly snug. I’ve never had side play there. With the plastic yokes, you can snug it perfectly every time. With the metal yokes, you will need shims if it is loose.

No i meant the condition of you sun gear with a picture but i think you already have put it back togueter wanted to compair it to my noisy rear typhon 3 diff when i spin it

 

[jondilly1974]

No i meant the condition of you sun gear with a picture but i think you already have put it back togueter wanted to compair it to my noisy rear typhon 3 diff when i spin it

If you’re asking for the old one, here it is after an 8S run.