Granite Jerry-rigged's Granite Mega 4x4

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Yup tons of guys on the Arrma Facebook page running 3s all day long


Sounds like it might be overgeared a little bit.
Yeah, I had that though. But it is already sooooo sloooooowwww.... LOL Maybe 20mph max

3s is kind of what I was thinking with the 2000kv 4074 motor. I'd probably need to drill a few pinions, though. I don't know how common 48p 5mm bore is.

Edit - well, I quick trip to the Amain website, they stock 48p 5mm bore RR pinions. Humm... Gonna need to test fit the motor. :)
 
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I was going to say Robinson racing makes 5mm 48p pinions. I use them on my 3665 3100kv brushless motor in my Ruckus
 
I am finding the lack of manual disturbing...
(That sounds better in a Darth Vader voice)

But really, why is the exploded diagram and parts list NOT part of the manual? grrr...

So after some homework, I see my truck probably has a 14t pinion, with a 17t shown as 'optional'. Does anyone know the actual range of pinions that fit these MEGA trucks? How big can I go?
 
I picked up a Granite 4x4 just today. After some growing pains, I'm finally enjoying it. The most aggravating part was having to remove the servo in order to reset the saver. There has to be a better way. I also acquired the Goolrc 3650 combo but, after seeing some responses here, I'm afraid of setting the truck on fire with it.
 
I picked up a Granite 4x4 just today. After some growing pains, I'm finally enjoying it. The most aggravating part was having to remove the servo in order to reset the saver. There has to be a better way. I also acquired the Goolrc 3650 combo but, after seeing some responses here, I'm afraid of setting the truck on fire with it.
Gool motors are great. The ESC's though are really hit or miss. Neither of mine that failed made a fire or melted the case, just a bit of smoke with one, the other still acts like it works, it just won't spin the motor.
 
I have 3 goolrc combos. 1 flamed & puffed while 2 are still going, only on 2S. I'm confident they would both grenade just like the 1st one on 3S.
 
I put a "Jrelecs 3650 3900KV RC Brushless Motor 4 Pole Sensorless Waterproof 3.175mm Shaft for 1/10 1:10 Scale RC Car" and a HW EZRun MAX10 in mine (figured I buy a decent ESC so it could be used in different stuff long term), set the punch to 1 and have not had any problems at all. With Megasty's input diff mod "only on rear" I have not had any issues, my boys run 2s and I run 3s if I drive it :)
 
I put a "Jrelecs 3650 3900KV RC Brushless Motor 4 Pole Sensorless Waterproof 3.175mm Shaft for 1/10 1:10 Scale RC Car" and a HW EZRun MAX10 in mine (figured I buy a decent ESC so it could be used in different stuff long term), set the punch to 1 and have not had any problems at all. With Megasty's input diff mod "only on rear" I have not had any issues, my boys run 2s and I run 3s if I drive it :)

Yeah its pretty hard to screw up a motor, and I would have to agree with you about the esc thing, I would rather spend money once than have to buy a new one all the time.
 
I've had trouble with the receiver. Occasionally, I have to reconnect the ESC to get it to work. Otherwise, the ESC will just blink red and only the steering will work.
 
I am finding the lack of manual disturbing...
(That sounds better in a Darth Vader voice)

But really, why is the exploded diagram and parts list NOT part of the manual? grrr...

So after some homework, I see my truck probably has a 14t pinion, with a 17t shown as 'optional'. Does anyone know the actual range of pinions that fit these MEGA trucks? How big can I go?
The Mega trucks have holes pre-drilled for 14t, 15t,17t and 27t. nice jump in between the two. I found this out by trying to install my Hobbywing SCT10 4000kv combo. I'm trying out the 27t first then maybe the 17t after buying a couple of hot racing pinions my LHS had.
 
Well, the brushed combo is out. I didn't mind the slow speed too much, but overheating every battery was silly. I dropped in my 'spare' BLX185 combo, with a 25t pinion - I oval'ed one of the 27t holes to make the 25t mesh correctly. Slipper is now as tight as I feel is safe with the plastic screw. Rest of the driveline is still stock.

One short test run (5 minutes) on 2s - big improvement. Better acceleration, and top speed (maybe 25mph? guessing). No wheelies. I think on 3s it would be perfect, but I don't have any 3s batteries that fit the truck. Guess maybe I need to buy some. :)

Before I buy some 3s, though, I think I want to try my 2350kv motor (4068) with the 27t pinion. That should give me a bit more speed, hopefully without impacting acceleration much, if at all.

20180318_200113.jpg
 
Swapped in some longer battery straps, so my oversize 3s packs sort of fit now. Did a test run last night, yeah, now it wheelies, and flips turtle quick. Pretty fast now too. :) I am planning a lunch bash, and will update after.
 
I love how the monster wedged in there just fits :p I'm sure Arrma screwed around with this setup. The actual brushless model does exists. Hopefully Arrma is waiting for this Hobbico stuff to blow over to release it, let alone having a way of getting to us ;)
 
Yeah, it is kind of funny, the motor had EXACTLY the right amount of room for the fancy sliding motor mount to work. Almost like they planned it. :D When they release the brushless version, I hope they drop in a 32p spur, because mine lasted 15 minutes. Or maybe 3 minutes after I found traction... LOL

Well, my lunch run was fun. :D Power a plenty on 3s. When I had traction, it was wheelies all over. I ran in the same creek bed from pic#2 above - lots of powder sand, bars, and some damp sand in low spots. With 4'-6' for run up, the truck launched great. I had a lot of bad landing - even hit a tree mid-air, no break issues. Most of the run was slower speed, in powder. Near the end of the run I found an open spot, part of it was flooded last week, but this week it was water free, but still damp sand. Traction galore, huge fun, till the spur let go. No surprise, a 1/8 scale 4074 motor on a plastic 48p gear.

Well, off to thread stalk @Megasty and try his 32p Yeti spur mod... :cool:
 
I did the same, thinking I could use the stock stuff with a 27t 5mm pinion. It ate the spur in under a minute & melted most of the plastic slipper parts - & that was 4S. I had to re-work that 32p spur 4 times to get it to where it transferred the minimum amount of power the lipo provided. If the slipper transferred all the power of 4S, I doubt the diffs would survive the initial punch. I have this on the backburner for now, or at least until I can think up some metal diff options. It still has some serious power on 3S & 4S, even if the only thing that is transferring the power is the spur's weight - & the slipper is completely tight.
 
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