Shims that work for Arrma diffs

[B1scu1T]

I believe you are missing just the one shim mentioned and IMO can be very important which is the 5x7mm shims for the outdrives. This keeps the outdrives from moving side to side through the 8internals of the differential but the shim is visible from the outside of the differential itself. I'll attach the image that I think is easiest to understand. But the info originally provided was absolutely excellent in comparison to others that can get a bit confusing for some that are not so familiar with rc differentials. Shout out to @B1scu1T forproviding such information (even a guy who hates spreadsheets actually very much liked the one he created for suggested parts shims bearing etc lol) well done and appreciate the time taken to provide the explanations @B1scu1T . The shims I believe you werent including are the 5x7mm that point to the two outdrive in the image. Hope that makes sense in a bit of a rush sry

Thanks Chris, my pleasure. Glad to hear people are finding it useful.

5x7 was the first one on the post with the green ticks though ?

 

[Oceanminded]

Thanks guys for the info, Not sure why I have Kyosho 96773 8x12x0.2mm and Kyosho 96644 8x10mm written down in notes. Would these shims go anywhere? Did not see them in the spreadsheet. Right now I have in my mind Mugen Seiki E026, Kyosho 96772 13x16x.15mm and Kyosho 96643 5x7.

 

[B1scu1T]

Thanks guys for the info, Not sure why I have Kyosho 96773 8x12x0.2mm and Kyosho 96644 8x10mm written down in notes. Would these shims go anywhere? Did not see them in the spreadsheet. Right now I have in my mind Mugen Seiki E026, Kyosho 96772 13x16x.15mm and Kyosho 96643 5x7.

I can't think of anywhere to put them in an Arrma mate, let me know if you remember what they were for and I'll add them in ?

 

[Terrance]

Hi everyone.

I transferred the information from this, along with some addtitional products I have found along the way into a spreadsheet. Thought it was only fair to share it.

I have also slowly been fleshing out the list of fixings as I prefer to order them individually from reputable screw suppliers, but it is by no means an exhaustive list (yet).
There is a bearings list, but this is also just a few items included here so I have all the information I need, quick to hand.

Happy to flesh the thing out with further data or comments if people have them.

https://docs.google.com/spreadsheets/d/1hsQBVZHxqyHskx2CS3niMWIqGJePsbG1hEpCDrVZXFM/edit?usp=sharing

Wow man that is some great stuff all im one place. I really appreciate the work you did here. Def gonna help to have a reference of all this stuff on one platform! Thanks again cheers!

 

[B1scu1T]

Wow man that is some great stuff all im one place. I really appreciate the work you did here. Def gonna help to have a reference of all this stuff on one platform! Thanks again cheers!

No worries.

Feel free to post here, or send me a message if you find anything additional that would help, or if you spot any errors.

 

[HeavyBag]

Where is everyone getting their 13x19x0.2 shims in the US?

 

[jondilly1974]

Where is everyone getting their 13x19x0.2 shims in the US?

Do you mean 13x16?

 

[B1scu1T]

Where is everyone getting their 13x19x0.2 shims in the US?

Just grab the part numbers and do a google search.

 

[HeavyBag]

Thanks. Someone was using 13X19X0.2 SHIMS DIN 988 behind the input gear bearing. I'll shim the input gear from the other end if need be.

 

[IrieWheeler]

Thanks for this reference! Arrma Diffs need their sweet whispers of adoration and gentle stroking apparently.

 

[B1scu1T]

Thanks. Someone was using 13X19X0.2 SHIMS DIN 988 behind the input gear bearing. I'll shim the input gear from the other end if need be.

I'm really sorry man, I thought I had replied to this but it doesn't seem to have posted... must have lost the internet or something.

You really want to shim the input gear on the inside of the gearbox, as this is how you can improve the mesh a little bit. You have to strike a balance between the 13x16 on the diff bearing, and the DIN bearings behind the input gear to get the gears to engage nicely.
I suppose you could shim just behind the gear, rather than the bearing... that would also work... not sure on the size you would need though.

You can get the DIM shims from normal fixing suppliers, they're a standard metric size.

 

[dontbeaburk]

Hey guys building a powerful Mojave EXB build and need some guidance on how to shim the Mojave’s diffs. I skimmed thru here and I am a noob so this is all very new to me. I’ve thrown ear plugs in the diffs instead of oil. And even then after a few mins the diffs just kind of give up. So I’m thinking shimming would be a great next step. Could someone please let me know what shims I should use for the Mojave? EXB build is max 5 800kv spool center 45:30T.

 

[B1scu1T]

Hey guys building a powerful Mojave EXB build and need some guidance on how to shim the Mojave’s diffs. I skimmed thru here and I am a noob so this is all very new to me. I’ve thrown ear plugs in the diffs instead of oil. And even then after a few mins the diffs just kind of give up. So I’m thinking shimming would be a great next step. Could someone please let me know what shims I should use for the Mojave? EXB build is max 5 800kv spool center 45:30T.

Hey bud,

This thread is related to the non-EXB diffs, they are quite different in build and design given that some of them are LSD, I don't think the specific product information on this thread is going to help you too much. Some of the discussion about the process of shimming might be useful to a degree.

I don't think you really want to have ear plugs in all of them, as the diffs actually have a function that would be essentially prevented by doing so. A diff allows the wheels to turn at different speeds, which if you plan to go round a corner is actually pretty important:

With that in mind, it doesn't surprise me if things are breaking when there is no give as you will end up with a load of tension building up across the differential when you're turning.

So although sticking ear plugs in the centre might be good to ensure you don't unload the power to the front when you peg the throttle, I would probably say you're better off looking at thick oil, somewhere between 200-500k, then for the F/R you probably want to be between 20k-100k, depending on preference. I certainly wouldn't be running a spool all the time if I was going off road as a primary function. You need some give in the drive train to allow the power to transfer effectively.

The only real way to know which oils you like is to try it, and the best thing to try first is stock weights.

Saying that, if you're running 8S with a huge motor and gearing, you're always going to have issues with the diffs as what you're doing is beyond what was ever intended for the car.

If you really are set on shimming the EXB diffs to perfection, then I'm sure it's possible, but if you're a noob then my advice would be to take a few steps back, learn the basics of servicing, get the experience, and then progress into the bonkers stuff.

 

[dontbeaburk]

Hey bud,

This thread is related to the non-EXB diffs, they are quite different in build and design given that some of them are LSD, I don't think the specific product information on this thread is going to help you too much. Some of the discussion about the process of shimming might be useful to a degree.

I don't think you really want to have ear plugs in all of them, as the diffs actually have a function that would be essentially prevented by doing so. A diff allows the wheels to turn at different speeds, which if you plan to go round a corner is actually pretty important:

With that in mind, it doesn't surprise me if things are breaking when there is no give as you will end up with a load of tension building up across the differential when you're turning.

So although sticking ear plugs in the centre might be good to ensure you don't unload the power to the front when you peg the throttle, I would probably say you're better off looking at thick oil, somewhere between 200-500k, then for the F/R you probably want to be between 20k-100k, depending on preference. I certainly wouldn't be running a spool all the time if I was going off road as a primary function. You need some give in the drive train to allow the power to transfer effectively.

The only real way to know which oils you like is to try it, and the best thing to try first is stock weights.

Saying that, if you're running 8S with a huge motor and gearing, you're always going to have issues with the diffs as what you're doing is beyond what was ever intended for the car.

If you really are set on shimming the EXB diffs to perfection, then I'm sure it's possible, but if you're a noob then my advice would be to take a few steps back, learn the basics of servicing, get the experience, and then progress into the bonkers stuff.

Thank you for your reply
Things haven’t been breaking just keep stop working haha so to speak. Every time the diffs slip I take them apart and service them and then it’ll work for a pack and the diffs will do what the do but nothing has broken. I’m thinking getting the mesh tighter keeping them synced will be a good next step.
I really meant noob in using the correct terms knowing what things are called and sizing what not.
Ive been in RC only for a few months but have background in FPV building drones and stuff.
I know the system I put in is overkill for the truck but so is lots of the systems people throw in their trucks. 800kv on 8s is much better than the 1650kv that others have tried.
i enjoy ripping these trucks apart learning about them.
But dealing with concussion stuff while learning about them has made it hard to know how to research or ask exactly what I’m after. Everyone has been very helpful so I’m hoping some one with Mojave shimming sees this and can help a bro out.
If someone can tell me what size of shims work in the diffs for the Mojave I’d be very appreciative

 

[jonesy67]

There is so much info to absorb in this one thread. The part numbers are truly helpful, thank you to everyone for sharing them.

 

[jonesy67]

Hi everyone.

I transferred the information from this, along with some addtitional products I have found along the way into a spreadsheet. Thought it was only fair to share it.

I have also slowly been fleshing out the list of fixings as I prefer to order them individually from reputable screw suppliers, but it is by no means an exhaustive list (yet).
There is a bearings list, but this is also just a few items included here so I have all the information I need, quick to hand.

Happy to flesh the thing out with further data or comments if people have them.

https://docs.google.com/spreadsheets/d/1hsQBVZHxqyHskx2CS3niMWIqGJePsbG1hEpCDrVZXFM/edit?usp=sharing

That is an excellent list. May I ask one question and suggest another part # for the list? What is the largest OD I can use for the satellite gears (I see 10 to 12mm)? and Tekno RC kit TKR1226 5x7x.2 for outdrive to diff case.

 

[B1scu1T]

That is an excellent list. May I ask one question and suggest another part # for the list? What is the largest OD I can use for the satellite gears (I see 10 to 12mm)? and Tekno RC kit TKR1226 5x7x.2 for outdrive to diff case.

There is a lot of vereity in the ACTUAL sizes of the shim when you take them out the packet, compared to what they say on the packet, but at a guess I would say an IRL 12mm shim would be the biggest, possibly 13mm at a push, but I don't have a spare diff case at the moment to check

 

[leroychurchill]

Will these shims work with the Arrma diffs? https://www.hobbytown.com/losi-gearbox-shims-8ight-2.0-losa4452/p30456

 

[B1scu1T]

Will these shims work with the Arrma diffs? https://www.hobbytown.com/losi-gearbox-shims-8ight-2.0-losa4452/p30456

If they work anywhere, it would be on the outside of the diff bearing to help set the mesh in the diff case, but given some of the 13x16 ones are a smidge too big, I would guess they'll be too big. Impossible to be sure without buying and testing though.

Have a look through my spreadsheet, I have put notes on ones that have been tested and reported as working. Just grab the model numbers and slap them in el googlo

 

[leroychurchill]

If they work anywhere, it would be on the outside of the diff bearing to help set the mesh in the diff case, but given some of the 13x16 ones are a smidge too big, I would guess they'll be too big. Impossible to be sure without buying and testing though.

Have a look through my spreadsheet, I have put notes on ones that have been tested and reported as working. Just grab the model numbers and slap them in el googlo

You have it listed on your spreadsheet, but there is no comment next to it. I think you are right about them being a bit too wide and would probably be hard to get them properly in the diff case.