Grom New release Arrma Granite Grom, mini basher

[fredw90]

Yes, that seems to be the issue. The outdrive is keyed into the sun gear with two little fingers that shear off under heavy load. The outdrive is secured to the sun gear via a screw inside the outdrive that threads into the gear. I don’t think it’s coming loose, it’s just a bad design.

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Thanks bro! I thought you already saw my build? It’s the 6350kv just like yours. Unbelievable power eh..? Fun as heck tho!!
I really should make a dedicated build thread for “Gromzilla”

Btw: if you send the mamba micro back to castle they’ll send you one with the bec inside. I didn’t want that stupid external one! Space is limited as is..

I wonder if that whole step can be avoided by just ordering the combo off of the castle website as opposed to somewhere else.

 

[Garcbomber]

I plan on putting an m3 helical insert in the composite and countersinking the outdrives to mate together. Then the case halves will be the weak point once the planetary set has 20M which can be remedied quickly with another insert or next size up SAE. We'll see how far that goes....

 

[Xjeepguy]

I plan on putting an m3 helical insert in the composite and countersinking the outdrives to mate together. Then the case halves will be the weak point once the planetary set has 20M which can be remedied quickly with another insert or next size up SAE. We'll see how far that goes....

My plan was to machine an intermediate shaft out of aluminum, and take its length out of the outdrive side, which would slot into both sides and be sandwiched in between by the screw. Seems a bit excessive for a $130 rig, but I think Horizon did us dirty with this diff.

I have the upgraded diffs preordered, I’m hoping this isn’t an issue with those.

 

[Garcbomber]

My plan was to machine an intermediate shaft out of aluminum, and take its length out of the outdrive side, which would slot into both sides and be sandwiched in between by the screw. Seems a bit excessive for a $130 rig, but I think Horizon did us dirty with this diff.

I have the upgraded diffs preordered, I’m hoping this isn’t an issue with those.

If the output material has good torsional toughness, that's a great solution. Can't wait for my slider to show up Friday and start dissecting!

 

[Hammer Down]

I wonder if that whole step can be avoided by just ordering the combo off of the castle website as opposed to somewhere else.

Possibly, I just know that if you order any of the 10 series combos with the mamba micro you’ll get the external bec. Castle told me that’s the last combo to get the new esc’s and most of the other combos have already been replaced.

 

[fredw90]

Possibly, I just know that if you order any of the 10 series combos with the mamba micro you’ll get the external bec. Castle told me that’s the last combo to get the new esc’s and most of the other combos have already been replaced.

Well that’s a pain in the butt lol.

I plan on putting an m3 helical insert in the composite and countersinking the outdrives to mate together. Then the case halves will be the weak point once the planetary set has 20M which can be remedied quickly with another insert or next size up SAE. We'll see how far that goes....

Since the whole diff is cheap enough to replace I’m wondering if I just pop the outdrive off clean off all the grease and throw a tiny bit of epoxy on there and seal it back up if that’ll work till some better diffs come out.

I don’t see a huge need for oil filled diffs on this small of a scale. I feel like majority of it will just leak out. If I can beef up the outdrive I think that’ll suffice.

 

[Hammer Down]

Well that’s a pain in the butt lol.

It is! But the folks at Castle (Rebecca) were so nice!! Only cost me $5 and a few days time.. They shipped the new one straight away and I didn’t have to pay for return shipping.

 

[Garcbomber]

20M is basically an earplug, only reason I don't want to fully lock it is for slight shock transfer through the plastic planetary set in the cold weather that will surely shear the output easily. It does appear overbuilt so it'll probably take it, but not 40-50mph tire speed onto high grip like some of the 3S brushless systems you guys are already swapping

 

[slick2500]

I still say 3s is too overkill for anything this small.

 

[Tex Koder]

I still say 3s is too overkill for anything this small.

Are you sure...

 

[Xjeepguy]

I still say 3s is too overkill for anything this small.

Definitely.

 

[CrashBoom]

I still say 3s is too overkill for anything this small.

I don't think it would even be drivable on 3S

 

[fredw90]

I bought two. Now I want a third…

 

[TN-RC]

@Hammer Down Is making me want to get one to do a road build. I think the whole thing would cost a little more than a TP4080 motor.

 

[Xjeepguy]

@Hammer Down Is making me want to get one to do a road build. I think the whole thing would cost a little more than a TP4080 motor.

That’s my next build. I want to see how fast one of these will go.

 

[TN-RC]

That’s my next build. I want to see how fast one of these will go.

Is it going to be the one with HR shocks?
I saw a photo somewhere on here of a Grom with foams on!

 

[fredw90]

Can anyone tell me what pitch the pinion/spur gears are? Are they 48? Also, whats the stock pinion size so I don't have to tear it apart before I order parts.

 

[Hammer Down]

Can anyone tell me what pitch the pinion/spur gears are? Are they 48? Also, whats the stock pinion size so I don't have to tear it apart before I order parts.

Mod 0.5 and 16T

 

[Xjeepguy]

Is it going to be the one with HR shocks?
I saw a photo somewhere on here of a Grom with foams on!

I have 2 sets of the HR shocks, the shorter ones will be for the speed truck, the longer ones are on my speed basher. Those shocks are extremely good on these trucks. Way better than stock.

 

[TN-RC]

I have 2 sets of the HR shocks, the shorter ones will be for the speed truck, the longer ones are on my speed basher. Those shocks are extremely good on these trucks. Way better than stock.

I would like to see the HR shocks vs the Aluminum upgrade onces they have.
Would you be willing to send me the numbers for the shorter ones you are going to run on road?