Granite Mega 4x4 Diff Input Gear Mod

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Megasty said:
https://www.ebay.com/itm/Brand-New-...944895?hash=item441c24b93f:g:yiAAAOSwCMtaVm65

This guy usually have the complete rollers, but he lists them one at a time.
Click to expand...

https://www.ebay.com/itm/Arrma-GRAN...e=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

This is the one I picked up. I think it's lacking servo saver assembly, which I got off Amazon. I also picked up the new Associated XP-R4 DVC with XP120 off a Trophy Rat to try on it and a no-name high torque servo. I've got some Traxxas 3665X chrome Monster Jam wheels for it already and have the Tekno hexes on the way also.
 
ptr1ck said:
https://www.ebay.com/itm/Arrma-GRANITE-4WD-4X4-1-10-Rolling-Chassis-Complete-Drivetrain-Suspension-26/112925835513?ssPageName=STRK:MEBIDX:IT&_trksid=p2057872.m2749.l2649

This is the one I picked up. I think it's lacking servo saver assembly, which I got off Amazon. I also picked up the new Associated XP-R4 DVC with XP120 off a Trophy Rat to try on it and a no-name high torque servo. I've got some Traxxas 3665X chrome Monster Jam wheels for it already and have the Tekno hexes on the way also.
Click to expand...

Lol, I completely forgot about him. I picked up his last Typhon roller & it came with the body. I also picked up 2 4x4 slippers from him.
 
Hey everyone, after reading this thread I was able to make my own gear mod thanks to you guys. I put the mod in my Senton Mega 4x4 and it didn't even make it 5 minutes. The spur gear is toast, and honestly looks like it rubbed against the chassis somehow. When I put the mod in there was no noticeable slop or play in it and now there is. So my question is does anyone think it could be possible that the play caused the spur gear to drop and get destroyed?
 
The only way I could see the spur gear moving is if you forgot one of the bearings. I think, more likely, is that it just stripped. When a spur goes, it tends to get the teeth chewed off all the way around. On mine, my pinion was not exactly centered, so it left a tell-tail fence on one edge.
20180320_205343.jpg


So time for the Yeti spur upgrade. I did make a video on it, but it needs an update. My aluminum spiral spacer failed. I am planning a rev2 of the spacer, made from .018 / 26g sheet stainless this time (available at hobby shops, or Amazon). Instead of a spiral, just use a single wrap. Also, unless you are using a huge motor (like the BLX185) I'd say to buy the 60t Yeti spur instead of the 56T that I got.

 
Mine looks exactly like yours did lol. I'm running a 3900kv brushless motor and I snapped the input gear twice on 2s. Looks like I'll be having to do this spur mod also, thanks for the help
 
Hi folks, I'd like to gain a little more insight, prior to actually opening this thing up (and so I can order parts before they are needed). I've attached two pictures to this post to help my understanding.

The first picture is the Granite differential exploded view. The part circled in green is what I understand to be the input gear, while the part circled in red is what I understand to break.

50r5mu.png


In this picture I've circled what I understand to be used to fix the broken part, one of the axles.

28lbb6w.png


Put simply, the input gear is hollowed out, so that the threaded part of the axle is inserted, and an appropriate pin is inserted through a new hole drilled from the side, through the hole in the axle.

Is there a part number to order for the pin?

***Edit***

I found these pins, and it sounds like the 2x10 mm was used for the initial mods, but perhaps a 2.4 mm pin would be better.

https://www.arrma-rc.com/part/AR713024

https://www.arrma-rc.com/part/AR713028
 
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Or you could ask if they have piano wire in a 2.5mm its much cheaper then the pins. You grt 3 feet of it for like 3 bucks. When you buy the new input gear it comes with the diff cup. Ask ur local hobby shop when they will be getting the new arrma hardened input gear and save ur self the trouble if u can wait. Sjppose to be end of May from my lhs.
 
fmaramara said:
Ask ur local hobby shop when they will be getting the new arrma hardened input gear and save ur self the trouble if u can wait. Sjppose to be end of May from my lhs.
Click to expand...

Good idea, I'll look into that.

On another note, why not just use JB Weld, or similar to fix the axle inside the gear, rather than using a pin? Or has something like this already been tried and I can't find it in the thread...
 
Yeah megasty tried it when made his first gear mod and because the axle wo t be perfectly centered it will need a bit of wiggle so when it spins it straightens itself out or you end up tearing up the modded input gear . In my case 3 input gears done and 2 broken, and tore up a slipper plate so i welded a shaft on the axle after cutting off the threads then slipped in in the input gear and drilled 2 holes under each bearing sobit was super strong. Used 2.5 piano wire and its not broken ........ yet. I wish i took pics
 
Have they come out with the hardened shaft yet? I was unable to find it.

I see other metal input gears, 13T I think, for the BLX. Could you not use the aluminum case with the metal ring and pinion gears from that? Or are they completely incompatible? You guys are way, way out ahead of me on this, so i'm just trying to gain some info.
 
Thunderbow said:
Have they come out with the hardened shaft yet? I was unable to find it.

I see other metal input gears, 13T I think, for the BLX. Could you not use the aluminum case with the metal ring and pinion gears from that? Or are they completely incompatible? You guys are way, way out ahead of me on this, so i'm just trying to gain some info.
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The the hardend one is out now. Here is a link to towerhobbies with the part.

https://www.towerhobbies.com/cgi-bin/wti0001p?&I=LXGWZB&P=Z
 
Thunderbow said:
Have they come out with the hardened shaft yet? I was unable to find it.

I see other metal input gears, 13T I think, for the BLX. Could you not use the aluminum case with the metal ring and pinion gears from that? Or are they completely incompatible? You guys are way, way out ahead of me on this, so i'm just trying to gain some info.
Click to expand...

No, the all metal input is not out yet.

And no, the BLX6s gears won't fit. At least, not without a huge amount of custom work.
 
Jerry-rigged said:
That part was first listed as "In stock soon" back in February. Then it was "Mid May" for a while. Now it is back to "On Order" whatever that means.
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Waiting game I guess. I just stumbled upon that didn't realize it said preorder. I just went a head and made my own input gear, but I hurt my spur gear. Idk if I wanna take on the challenge to mod a spur gear yet. I am running a goolrc brushless setup so it's definitely not that most powerful setup.
 
i was told by tower today 7/16 its going to be aug now iam so sick of this with arrma
 
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