Big Rock Things you need in order to do a 6s conversion on arrma 3s big rock
- Thread starter ROCKY OP
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crazyjr
Active Member
- Messages
- 95
- Reaction score
- 60
- Arrma RC's
- BigRock 4x4
It depends on what you want it to do, What's your intention? To make pizza cutter tires? To go 100+ MPH? Each one needs different things.
For me personally it's fast enough (I'd probably lower the speed by about 5mph), but I'd love more runtime and lower motor/esc temps. So my plan is to not worry about amps (because i plan to lower their use) as much as the voltage and KV of the motor. My plan would be to use a 1200 KV motorand 6s pattery pack, roughly equiv. to the 3s pack (weight wise), why is that important? More work= more wear, higher weight is harder to move, causing parts not designed for the load to wear faster or even break. The setup i'd use would be, weight wise similar to the stock equipment, but offer a stronger torque at a lower RPM and with the appropriate gearing for the desired speed. Now you don't need size in the motor, that is a misconception propped up by the X maxx and the 1/5 scale arrma trucks. They need bigger motors because they are BIGGER TRUCKS, not because they are the only low KV solutions. You can find 540/550 sized motors with the KV you need (My aim is 1200KV), heck you can find them in almost any size. Not sure if they are made anymore but the Tekin ROC crawler motors are available in lower KV's and rated for up to 6s (depending on KV) and they are within a couple MM's of the BR stock motor. There are a lot of crawler motors that could probably do the job, you just have to find the right gearing
The point is, you need a plan for your truck or you'll be wasting parts. If you want big power for speed, you might need a thicker MM for crashes or even torque twist, If you are after efficiency you might can save some money by keeping some of the stock pieces. That said, I will eventually be upgrading to the CVD's, because I'm already having issues with the stock half shafts in my BR. BTW check out Castle creations, they have a Mamba x esc that is smaller than the Firma and unless you plan to gear to the moon, should handle whatever you need power wise up to 6s
For those who say small motors can't have low KV's or high torque, I offer a project from my past (Wish i still had it. This was my RC10 GT blue chassis I converted to electric in around 2007, The motor is a Lehner 1200XL (1200KV 2 pole) that is the exact same size as a 540 brushed motor, but is a torquey little bugger. These motors were once the go to for the Emaxx trucks (the predecessor to the maxx truck) The battery pack was a 5s 2500 Flightpower 30C pack, this pack never had issues pulling that truck around. The truck was geared to about 40 and would run nearly 30 minutes, with no heat issues with any parts (Motor, battery or esc). One time while playing on a track I passed a 1/8 nitro buggy in a wheelie. At the time I built this, Brushless was just starting to assert dominance over nitro. The only sensored setups were from Novak and Tekin, Hobbyking was not even in the picture back then, much less dominating the market. Anyways here's the truck, hope you like it
Last edited:
Jessica Hyde RCPD
Member
Just watch my last Big Rock video. The axles are necessary if you change tires and get traction a lot. So far, mine only popped apart and was able to go back together. The M2C motor mount is best because it seals dirt and doesn't bend like the other aftermarket ones. The HR Yoke is necessary in the rear. I also run a metal slipper clutch with HR aluminum slipper pads x4. Metal gears of course. I also recommend getting the ceramic hybrid from Acer Racing on the center driveshaft. I put HR pivotballs on stock rods. I run the 6s BLX system on 4s most times. I like the Granite tires pretty good.
- Messages
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- Location
- Pace, FL
- Arrma RC's
- 4x4-Mega
- BigRock 4x4
- Granite
- Kraton 6s
- Kraton EXB
- Mojave EXB
- Senton 3s
- Senton Mega
GH hooked me up with one of his 3D printed plates and my current V5 150 amp ESC fits perfecty in my BR V3 now on 6s. Well worth the minimal cost to get his plate instead of guessing at what to do with the ESC. My wife even commented “wow I bet he makes a fortune off these”...
Here is how clean of mounting the 150 esc is inside the chassis of my V3 BR (love the extra tab for the power switch);
GREAT JOB GH !!!
Glad it works and your happy! GL with your setup!
I noticed you have a stock servo. That will go out eventually. I would recomend an animos 35kg and a 25t servo saver to go with it.
- Messages
- 376
- Reaction score
- 629
- Location
- Pace, FL
- Arrma RC's
- 4x4-Mega
- BigRock 4x4
- Granite
- Kraton 6s
- Kraton EXB
- Mojave EXB
- Senton 3s
- Senton Mega
Ok, finally picked up a matching battery to my existing 5200 mah 50c 3s so I could try the Big Rock on 6s and HOLY POW WOW KAZZOOOOWIIIEEEE!!!!
Yeah, i'm about to buy @StephenSchandelmayer's 6s beefcake bigrock, and I can't wait to rip it on 6s!
I just thought, you might want to strap down the 3 motor wires to something, so they don't bounce around. If they do, the wires will eventually fray and rip off. Same with the battery leads.
- Messages
- 376
- Reaction score
- 629
- Location
- Pace, FL
- Arrma RC's
- 4x4-Mega
- BigRock 4x4
- Granite
- Kraton 6s
- Kraton EXB
- Mojave EXB
- Senton 3s
- Senton Mega
Yeah the above photo was the initial shake down and once Im sure its how I want it, everything gets zip ties or velcro’d to “stay put”.
Can you help with a fan mount anything I've seen won't work as the motor fits snug
