Granite Arrma Granite 4x4 6S BLX

[Megasty]

You knew this was coming, muhuhahahahaha

I have the same system in my Pro-MT 4x4 so I took the badlands mx28 from it, added the 17mm hex from Axial AX8000, some fender washers from Menards & the beast awakens

I beefed up the springs & links. Everything came from parts I had on-hand or from spares.

Of course I modded the diff input gears & spur-pinion for 32-pitch

I've only ran it on 4S so far (I can't get a 6S battery to fit in it w/o longer straps ) & it's a juggernaut. I'm seriously impressed on how the plastic drivetrain, shafts, & diffs can handle all that power (stares at old bucket full of broken Slash & Stampede parts )

I'll try to get a video uploaded later when the freezing rain stops. Seeing the mx28s turn into flying saucers is something I never thought I see on this rig. Now lets see what Arrma comes up with

 

[Megasty]

She's a little dirty

I also had to redesign the slipper a bit. The plastic piece that held the bearing, retained the spur, & seated the spring melted on 4S. Having one part do so much & having to replace it is a PITA

So I replaced it with a combination of bearings, washers, & the inner rings of bearings.

No more plastic garbage, err I might find a M8 lock nut if that red slipper adjuster decides to give up the ghost.

I may as well give this a shot on how I made this thing . . .

Here are the parts

All the stock parts besides the plastic nonsense, HR Axial Yeti 60t steel spur, Yeti slipper plate, 2 1/4" washers (I grinded one down), Four 10x15x4 bearings, & One 8x18x6 bearing.

The hardest part was making this compound bearing holder spring seater thing.

First, I took apart a 10x15x4 bearing & the 8x18x6 bearing to get the inner rings. I then had to remove 0.2mm of the whole outer surface of the 8x18x6 inner ring so I could press the 10x15x4 inner ring on top of it (shown on the right)

I then took another 10x15x4 bearing & press that on top of the previous combination.

I then took another 10x15x4 bearing, obtained the inner ring, removed 0.3mm from its outer surface & pressed it into the Yeti spur gear.

I grinded down any of the inner ring so that it was flush with the hole of the spur gear.

Then I assembled it starting with the combination retainer, grinded, washer, & whole washer. The grinded washer need to meet up with the inner ring on the retainer & not be thick enough to meet the outer ring. This allows the bearing to freely move.

Next is the last 10x15x4 bearing and the Yeti spur. This bearing acts as a spacer & isn't functional.

Then the Yeti slipper plate.

The rest goes on like normal.

I think I will keep it like this although I haven't run it on dry ground yet & the forcast isn't too promising. But it's ripping through 6" of melting snow with no problem. That has to be hell on the drivetrain since it take half to full throttle to do it even with the super ballooning tires

 

[Jerry-rigged]

Was the diff input mod just to allow the Yeti slipper shaft to work? I am seriously impressed that the plastic diffs are holding. It will be interesting to see what happens when the snow melts and traction comes back.

 

[Megasty]

The diff input mod was first, because I broke 3 of them . . .

 

[Jerry-rigged]

oh, was the mod to add the cross pin?

 

[Megasty]

Pretty much. I just drilled the gear out, made a hole for the pin, inserted axle, & done. The simplest mod that's easily taking the most abuse, especially on 4S.

 

[Bmansdad]

You knew this was coming, muhuhahahahaha

View attachment 14687

View attachment 14688

I have the same system in my Pro-MT 4x4 so I took the badlands mx28 from it, added the 17mm hex from Axial AX8000, some fender washers from Menards & the beast awakens

I beefed up the springs & links. Everything came from parts I had on-hand or from spares.

Of course I modded the diff input gears & spur-pinion for 32-pitch

View attachment 14689
View attachment 14690
View attachment 14691
View attachment 14692
View attachment 14693
I've only ran it on 4S so far (I can't get a 6S battery to fit in it w/o longer straps ) & it's a juggernaut. I'm seriously impressed on how the plastic drivetrain, shafts, & diffs can handle all that power (stares at old bucket full of broken Slash & Stampede parts )

I'll try to get a video uploaded later when the freezing rain stops. Seeing the mx28s turn into flying saucers is something I never thought I see on this rig. Now lets see what Arrma comes up with

SWEET! You are a true Pioneer and hero to many amateur Mega 4x4 owners. I think we are all interested in how the 17MM hub swap went. I tried Traxxas Hex adapters, but could not find pins that would fit. More details on this piece please..

 

[Megasty]

The 17mm hex is Axial part AX8000. I had some in a bag of extra Yeti XL parts. They are a direct fit. You can use a 1/4" washer to put on the axle b4 you tighten down the nut.

In order to use the aluminum hexes, you will have to find adapters that will snuggly fit over a 6 mm axle & a 2.3-2.5x16 or 17 pin. Finding the pin is easy. I found an adapter on ebay that might work so I'll tell you when I get it.

 

[Bmansdad]

The 17mm hex is Axial part AX8000. I had some in a bag of extra Yeti XL parts. They are a direct fit. You can use a 1/4" washer to put on the axle b4 you tighten down the nut.

In order to use the aluminum hexes, you will have to find adapters that will snuggly fit over a 6 mm axle & a 2.3-2.5x16 or 17 pin. Finding the pin is easy. I found an adapter on ebay that might work so I'll tell you when I get it.

Awesome! Thanks. The AX8000's are pretty scarce right now...cant find them anywhere.

 

[Megasty]

Tired of breaking axles & outdrives . . .

Just brew up a batch of double heat-treated, oil-quenched steel hardness

 

[Megasty]

It's finally done

I had one last problem, the bloody plastic slipper cap. It didn't melt or anything, it just kept coming undone. I had that happen once with the 3S blx 85 setup but I just re-tightened it & kept on going. I played around with the idea of using a lock nut, but it was way too big. So I finally gave in to the easy way out . . .

I tightened the cap to its physical limit. Drilled a hole straight through it & the slipper shaft. Then screwed a 2.5x12 M4 axle pin. The slipper still functions & I think it's delivering the most power to the drivetrain w/o eliminating the slipper entirely. Just in case this fails, I have a modded 12mm hex aluminum wheel adapter, doubled tapped for the slipper shaft & pin. I could blue-loctite this piece so it only moves when I want it to.

I still don't have dry ground to test this on but it can easily do half-throttle wheelies half way down the block just like my Outcast, & that is only on 4S. It really doesn't need 6S. 4S is already pushing this car to the limit. It's stupid fast even on wet pavement. So I'm dreaming of ripping this thing apart in a dusty whirlwind bash & blowing some tires during a speedrun

 

[Megasty]

Chronicles of Destruction

Ok, the truck isn't a tank, yet

During a bash session full of cartwheeling & tumbling back-flips, I broke the front bumper, ripped off the wheelie bar, & managed to mangle the rear end of the body.

So I repaired the wheelie bar for a 2nd time, made a bumper, & wheelie bar skid plate . . .

The skid plate has foam to help cushion the blow.

The bumper/skid plates will also protect what's left of the stock parts.

Now this . . .

I finally wrecked the diff ring & pinion

But it wasn't necessarily due to the power of the car. If you look closely at the diff cup you'll see it has the remnants of silicone oil in it, 30k cst to be specific. This was another failed experiment.

All bashing until now has been with the stock diff cups with its tad bit of grease inside. I prepared 2 diff cups full of 30k silicone oil to see it that would affect traction & handling. All I got for an answer was a loud CRRUUUUUUNCH out of the rear diff after the 3rd brake. There was 14 broken or chipped teeth on the ring & NO noticeable broken/chipped teeth on the pinion. All the damaged teeth on the pinion appeared to have been caused due to grinding. The force of the braking was transferred from the pinion to the to the ring. The teeth on the ring couldn't take it & chipped. These chipped teeth then proceeded to to grind the pinion.

So what happened? Obviously the diff with the oil weighed more so I started there. The stock cup was 58g while the oil cup was 76g, a 31% increase Of course something is going to fail if you increase its operating load by a ~1/3. But there's other factors too, like torque bias & rotational inertia. Both increased exponentially with the addition of the oil. This system was doomed from the start.

Don't modify the stock diffs, is what I would say if I had to get anything out of this. The stock diffs can easily handle 3S & 4S power, even with an 1/8 scale system.

But the most important part makes all the above irrelevant anyway. The diff cups can't hold oil very well. Both diffs were leaking terribly from the outdrives when I took them out

 

[Nosedive4130]

Thanks for trying that out. You just saved a lot of people (me included) a headache.

This was going to be one of the next things I was going to try.

I wonder what it would take to lock the diffs all together or if there are any other compatible parts that could be modified to drop in...

 

[Megasty]

Thanks for trying that out. You just saved a lot of people (me included) a headache.

This was going to be one of the next things I was going to try.

I wonder what it would take to lock the diffs all together or if there are any other compatible parts that could be modified to drop in...

I don't think the diffs would be able to handle being locked (let alone diff fluid). But I am looking into metal diffs. I have access to parts for over 100 cars & the only diff that might work in this thing as a drop in is the Nero . This would let you make a center diff, replace the axles & driveshaft. It would be a little 6S demon

 

[Megasty]

SWEET! You are a true Pioneer and hero to many amateur Mega 4x4 owners. I think we are all interested in how the 17MM hub swap went. I tried Traxxas Hex adapters, but could not find pins that would fit. More details on this piece please..

I just got the hexes in, 3 days from CA to IL. They have the slightest bit of play in them just like I hoped. They definitely made these for this type of axle. But the pins it came with are too small. Get some m2.5x17. It has pin holes for m2 & m2.5.

https://www.ebay.com/itm/4-Adapters...e=STRK:MEBIDX:IT&_trksid=p2060353.m2749.l2649

The quality is tier 1, superior cut & finish.

 

[Megasty]

Here's a little test video in my sketchy yard. 6S Lipo. A few 1/4-1/2 throttle launches & sprints, brush escaping, launch flipping, & maximum ballooning This thing is crazy. I think it may explode if I hit full throttle

My one-handed driving sucks

 

[Nosedive4130]

I applaud your self control and limited use of throttle.

 

[Megasty]

The badlands are almost write-offs. I ripped them up on 6S with the pro-mt 4x4. I just don't want them to wreck this thing, yet

 

[Megasty]

First running video

I just wish it had metal diffs.

 

[Nosedive4130]

Holy Wheelies Batman! You weren't kidding about the tires ballooning!

Did you have any gear slippage? Is that what I was hearing happen when everything hooked up and got traction?