Kraton alternative diff gears for Arrma diff cups

[Mitchell looper]

PowerDubbs, I see your'e a fellow veteran, thank you for your service.
As to your issue with the diff gears. I did some research for you since I have an extended background with off road racing.
What I found is that although most of the current off road racing diffs have the 6 mm drive cup shafts. The MUGEN mbx7 had the 5 mm
drives. I checked the overall demensions and they are the same. The slot in the mugen is longer and would allow the drive shaft to slide further into the drive cup. this could in turn cause you to bend an out drive. The way to solve this problem is to pick up some 5/16 diameter rubber orings and put them into the drive cup. this will take up the space to put the drive shaft in the correct place.(btw, this can be done on about any of the Arrma outdrives).
I checked the fit with the mugen outdrive to the Arrma gears and it feels about the same as the Arrma outdrives. as far as the gear mesh goes. I did take out the spider gear shims to loosen up the fit just a little bit. Will this hurt anything? Not in my openion as the spider gears ride against the aluminum guide bushing. Next I tried the mbx7 internal gears. After the build both felt the same to me as far as gear mesh goes. I did build both diffs dry
(no fluids) and to be honest they both felt a little crunchy to me. Would you notice this with 100,00 diff fluids in the center? I doubt it.
If the gears are not to your liking you might want to add another conicial gear seal gasket and see how that feels.
The gear ratio might be a concern. The stock gears( to my count) was 11 spider 21 Sun gear. the Mbx7 is 10 spider and 18 sun gears
that would put the ratio really close but I do not know how it would effect the drive system unless you replace all the gear in the all 3 diffs.
the part numbers for the Mbx7 are:
On amain hobbies
Outdrives
muge 0228 (front rear outdrives) 16.74
muge 0229 (center diff) 16.74
spider gears MUGEC 0230 6.49
sun gear muge 0230 8.49
I can't say as to the quality of the Arrma gears
but I do know that the quality of the mugen parts are excellent and been proven for many years.
Just a note: if you file the burrs off any drive cup in the slots, they will last a lot longer.
Remember this. If you land on power with any diff, It is likely to bust the gears.
the pic below has one of the Mugen outdrives mounted in the diff.
hope this helps.

 

[PowerDubs]

Diggin around-

Arrma

Stock gears 10 & 20 tooth. https://www.amainhobbies.com/arrma-differential-gear-set-ara310436/p409428

We know the back of the stock large gear is hollowed out and the gear breaks. We know the back of the small gears are solid.

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Mugen

10t sat, hollowed spot for oring on the back? https://www.amainhobbies.com/mugen-seiki-internal-diff-spider-gear-10t-mugc0230/p1773

18t confirmed solid back unlike the Arrma https://www.amainhobbies.com/mugen-seiki-18t-differential-gear-2-muge0230/p29854

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Associated

https://www.amainhobbies.com/team-associated-rc8b3.1-htc-differential-gear-set-asc81380/p661949

10 & 20 like stock. Unsure if they fit.

Small gears have the same open area on the back, maybe for an O-ring like the Mugen. See 2nd picture.

Finish and shape visually look better than stock- and beefy on the front- but back is even more open than the Arrma, although still may be stronger?? See 3rd picture.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~



Xray

https://www.amainhobbies.com/xray-v2-differential-bevel-satellite-gear-set-xra355031/p635565

These are 10t & 20t just like stock, fully solid on both the big and small gears.

They stated as- "The gears are heat-treated and machined for ultra-precision and smooth operation."

None of the other gears mention heat treating from what I can see.

Couple the heat treat with all solid back and same teeth count as stock and they may be the best choice if they fit...I have no idea of outdrive shaft diameter, any pin diameter, pin length, gear diameter, etc on ANY of these gear sets other than stock!

 

[Mitchell looper]

Guys,What we have to consider here is the ovarall length of the the assembled diff themselves. that's from outside bearing to bearing. If it is too long it won't fit in the motormounts or front and rear diff housings. and if the inner gears themselves are not the same demesions as the stock gears that will change how they fit in the stock diff cup. Most of the current off road racing diff cups are not the same length as the Arrma bearing to bearing and have 6mm drive shafts.
there are a lot of variables that have to be conidered so be careful. hope this helps.

 

[PowerDubs]

Understood. That is why I put in disclaimers that I have no idea what will fit.

That being said- I don't like parts breaking if I can find a way to improve them.

So I broke a rear diff gear very easily and quickly. So in looking at it, I see the cutout back section. To me that weakens it.

I see the outdrive pin broke into 3 pieces. I see cheap cast metal.

I am not concerned about light weight or material cost savings or price point like a manufacturer.

So if I can find a source for heat treated, full filled/formed backed, stronger material, thicker material parts- I'm going to do it.

I understand there is a reason the other companies opt for 6mm outdrive shaft over 5mm, thicker pins, longer pins, etc- they are selling complete vehicles to the public so they balance material & cost with design.

Problem is- Arrma is the company offering the fun vehicles that are mostly durable for crazy driving. So we need to work within their design constraints for the time being.

What that means is there is a market for hardcore parts that readily fit the Arrma cars.

Given how there are 3 identical diffs on a single car in most of us- and plenty of hardcore guys- plug and play- solid, better material, heat treated diff gears / pins seem to be a no brainer market for someone.

You are currently the go-to guy for ultimate enthusiast durability. Step up to the plate, swing, home run...

 

[Mitchell looper]

I understand you fustration with this. But in the rc car market cost is everything to a company. As far as I know all the diff gears are investment castings. Some are better than others is the difference. To have these gears machined would be very expensive.
the Mugen Mbx7(only) not the MBX8 gears are very good as I have been dealing with this brand name for a very long time. and they do fit in the existing Arrma diff case.
they were a little crunchy to me but felt pretty much like the stock gears did. this is due to the fact that they are cast and have rough edges on them form casting. I know that the bashing market does not prepare new diffs like serous off road racers. It is a process that takes time.
As an example: The racer always breaks in his diffs. that means you build them up and then, chuck the diff cup in a drill.
Hold the diff and spin it untill it gets too hot to handle. Then do the next one. Let them cool down and repeat the procedure untill the gears feel smooth and spin freely. this method allows the rough edges from the casting process to wear in and get smooth.
If a diff feels too crunchy you can add another conical gear gasket. This will give you a little more play in the gears.
Hope this helps.

 

[PowerDubs]

What about these- https://www.amainhobbies.com/mugen-seiki-htd-differential-gear-2-20t-muge2239/p587569

Says they are for the MBX7 according to this page- http://www.mugenracing.com/mugen-seiki-ht-differentials/

They have the little 10t gears listed on that page as well.

 

[Mitchell looper]

I can't say about those gears. I don't have any to compare.

 

[iLikeRCs]

PowerDubbs, I see your'e a fellow veteran, thank you for your service.
As to your issue with the diff gears. I did some research for you since I have an extended background with off road racing.
What I found is that although most of the current off road racing diffs have the 6 mm drive cup shafts. The MUGEN mbx7 had the 5 mm
drives. I checked the overall demensions and they are the same. The slot in the mugen is longer and would allow the drive shaft to slide further into the drive cup. this could in turn cause you to bend an out drive. The way to solve this problem is to pick up some 5/16 diameter rubber orings and put them into the drive cup. this will take up the space to put the drive shaft in the correct place.(btw, this can be done on about any of the Arrma outdrives).
I checked the fit with the mugen outdrive to the Arrma gears and it feels about the same as the Arrma outdrives. as far as the gear mesh goes. I did take out the spider gear shims to loosen up the fit just a little bit. Will this hurt anything? Not in my openion as the spider gears ride against the aluminum guide bushing. Next I tried the mbx7 internal gears. After the build both felt the same to me as far as gear mesh goes. I did build both diffs dry
(no fluids) and to be honest they both felt a little crunchy to me. Would you notice this with 100,00 diff fluids in the center? I doubt it.
If the gears are not to your liking you might want to add another conicial gear seal gasket and see how that feels.
The gear ratio might be a concern. The stock gears( to my count) was 11 spider 21 Sun gear. the Mbx7 is 10 spider and 18 sun gears
that would put the ratio really close but I do not know how it would effect the drive system unless you replace all the gear in the all 3 diffs.
the part numbers for the Mbx7 are:
On amain hobbies
Outdrives
muge 0228 (front rear outdrives) 16.74
muge 0229 (center diff) 16.74
spider gears MUGEC 0230 6.49
sun gear muge 0230 8.49
I can't say as to the quality of the Arrma gears
but I do know that the quality of the mugen parts are excellent and been proven for many years.
Just a note: if you file the burrs off any drive cup in the slots, they will last a lot longer.
Remember this. If you land on power with any diff, It is likely to bust the gears.
the pic below has one of the Mugen outdrives mounted in the diff.
hope this helps.

hey, what are "the burrs of a drive cup in the slots"

PowerDubbs, I see your'e a fellow veteran, thank you for your service.
As to your issue with the diff gears. I did some research for you since I have an extended background with off road racing.
What I found is that although most of the current off road racing diffs have the 6 mm drive cup shafts. The MUGEN mbx7 had the 5 mm
drives. I checked the overall demensions and they are the same. The slot in the mugen is longer and would allow the drive shaft to slide further into the drive cup. this could in turn cause you to bend an out drive. The way to solve this problem is to pick up some 5/16 diameter rubber orings and put them into the drive cup. this will take up the space to put the drive shaft in the correct place.(btw, this can be done on about any of the Arrma outdrives).
I checked the fit with the mugen outdrive to the Arrma gears and it feels about the same as the Arrma outdrives. as far as the gear mesh goes. I did take out the spider gear shims to loosen up the fit just a little bit. Will this hurt anything? Not in my openion as the spider gears ride against the aluminum guide bushing. Next I tried the mbx7 internal gears. After the build both felt the same to me as far as gear mesh goes. I did build both diffs dry
(no fluids) and to be honest they both felt a little crunchy to me. Would you notice this with 100,00 diff fluids in the center? I doubt it.
If the gears are not to your liking you might want to add another conicial gear seal gasket and see how that feels.
The gear ratio might be a concern. The stock gears( to my count) was 11 spider 21 Sun gear. the Mbx7 is 10 spider and 18 sun gears
that would put the ratio really close but I do not know how it would effect the drive system unless you replace all the gear in the all 3 diffs.
the part numbers for the Mbx7 are:
On amain hobbies
Outdrives
muge 0228 (front rear outdrives) 16.74
muge 0229 (center diff) 16.74
spider gears MUGEC 0230 6.49
sun gear muge 0230 8.49
I can't say as to the quality of the Arrma gears
but I do know that the quality of the mugen parts are excellent and been proven for many years.
Just a note: if you file the burrs off any drive cup in the slots, they will last a lot longer.
Remember this. If you land on power with any diff, It is likely to bust the gears.
the pic below has one of the Mugen outdrives mounted in the diff.
hope this helps.

hi, I just saw they don't have those exact diff outdrives any more, only some with holes.. https://www.amainhobbies.com/mugen-seiki-front-rear-differential-cup-outdrive-2-muge0228/p29852 - do these still fit?

EDIT: I just saw they're ft and rear

 

[PowerDubs]

Just heard back from Xray- unfortunately those are a 6mm outdrive.

 

[iLikeRCs]

sad

 

[iLikeRCs]

PowerDubbs, I see your'e a fellow veteran, thank you for your service.
As to your issue with the diff gears. I did some research for you since I have an extended background with off road racing.
What I found is that although most of the current off road racing diffs have the 6 mm drive cup shafts. The MUGEN mbx7 had the 5 mm
drives. I checked the overall demensions and they are the same. The slot in the mugen is longer and would allow the drive shaft to slide further into the drive cup. this could in turn cause you to bend an out drive. The way to solve this problem is to pick up some 5/16 diameter rubber orings and put them into the drive cup. this will take up the space to put the drive shaft in the correct place.(btw, this can be done on about any of the Arrma outdrives).
I checked the fit with the mugen outdrive to the Arrma gears and it feels about the same as the Arrma outdrives. as far as the gear mesh goes. I did take out the spider gear shims to loosen up the fit just a little bit. Will this hurt anything? Not in my openion as the spider gears ride against the aluminum guide bushing. Next I tried the mbx7 internal gears. After the build both felt the same to me as far as gear mesh goes. I did build both diffs dry
(no fluids) and to be honest they both felt a little crunchy to me. Would you notice this with 100,00 diff fluids in the center? I doubt it.
If the gears are not to your liking you might want to add another conicial gear seal gasket and see how that feels.
The gear ratio might be a concern. The stock gears( to my count) was 11 spider 21 Sun gear. the Mbx7 is 10 spider and 18 sun gears
that would put the ratio really close but I do not know how it would effect the drive system unless you replace all the gear in the all 3 diffs.
the part numbers for the Mbx7 are:
On amain hobbies
Outdrives
muge 0228 (front rear outdrives) 16.74
muge 0229 (center diff) 16.74
spider gears MUGEC 0230 6.49
sun gear muge 0230 8.49
I can't say as to the quality of the Arrma gears
but I do know that the quality of the mugen parts are excellent and been proven for many years.
Just a note: if you file the burrs off any drive cup in the slots, they will last a lot longer.
Remember this. If you land on power with any diff, It is likely to bust the gears.
the pic below has one of the Mugen outdrives mounted in the diff.
hope this helps.

the mugen one is a bit thicker in one spot, does it still fit in the front or rear diff cases?? or center only??

 

[piccopower]

Sorry for bringing this thread back to life. Reading it tells me there was no conclusion here. Did we find out if the MBX7 gears mentioned above work? What about the Team Associated gears pictured? I'm just looking to rebuild and want to do it with the strongest gears possible.

Or will this work? https://www.amazon.com/gp/product/B000BMP9FI/ref=ox_sc_act_title_1?smid=A3QJ5AT0BERQ2F&psc=1

 

[Yas]

I would also love to know if there's any other parts out there that sell stronger pins and diff gears that can fit in the 6s diffs. I heard people have cut down screwdrivers to make their own pins but I'd rather buy them as parts. I've gone through 2 stock planetary gears in the rear and at least 4+ pins across the F&R diffs

I've used the GPM hardened steel diff set in the rear since and I've yet to break any gear, although I had to add an extra gasket in order for the internals with Mugen shims to mesh perfectly. This widened the diff a little, but I still managed to shim the input and crown gear for a perfect mesh. It's also worth mentioning the GPM planetary gears are solid and not hollowed out like the stock ones!

I'm still looking out for aftermarket pins though. I feel like it's only a matter of time before another one breaks and could potentially lead to another stock planetary gear to fail (or vice versa)

 

[Dcole726]

Is there anyone who makes a better ring and pinion gear for kraton 6 s

 

[Rcproponent]

Is there anyone who makes a better ring and pinion gear for kraton 6 s

Gpm.. only bad thing is most of them come from China and take a month haha

 

[Dcole726]

I just bought a complete mbx7 diff I will post results
I have broke 4 outdrives at the pin hole I hope these are stronger should I run lighter diff fluid or tires with less traction

 

[blindy]

As far as I remember you can use all internals of the MBX7 diff except the cross pins (which are too long for the Arrma diff).

 

[Dcole726]

I read somewhere the outdrives should work too and be better quality "that's what I keep breaking"

 

[Rcproponent]

Interested to see if these are a stronger solution...

 

[iLikeRCs]

Gpm.. only bad thing is most of them come from China and take a month haha

Are the GPM ones really stronger? Because on ebay there are some that look 100% like the gpm ones and with TERRIBLE reviews