Big Rock 3s to 4s conversion

[bigrockva]

When upgrading the 3S BRCC V2 to 4S, what other parts will I need to upgrade to metal instantly if any? I’m assuming definitely driveshafts?

 

[vader]

Probably worth cross referencing with the outcast 4s , that Should give you an idea of what parts would need upgrading and what parts will hold up, I’m doing something similar with my Granite.

 

[parcou]

I thought I read many times one item going 3 to 4s the driveshaft will not handle it...will eat them up. There was a recent post on that those need to be upgraded for the added power there is an Arena recommendation. Sure there is more that one I do remember reading a lot.

 

[stiles]

I’m doing the same thing right now. I can’t find any good metal drive shafts. They have the cvd ones but they are out of stock. The 4s outcasts has plastic drive shafts so it can work but it’s all about having the slipper set right. I’ve looked into metal differentials too and hot racing makes them but it would 200 to do the whole car. I’m just gonna get mine going and see what breaks

 

[suchtragedy]

I've upgraded several Arrma 3s trucks to 4s and even 6s but in the end I end up just running them at 3s only. 4s and higher on a slipper clutch + plastic drivetrain = more trouble than it's worth. You end up spending close to the cost of a 6s RTR just to upgrade everything on the truck to make it semi reliable (the 4s stock trucks didn't sell so well for many of these reasons).

Not telling you what to do or anything just letting you know my experience. If you're still wanting to go the 4s route at a minimum I would get the 4s slipper that has the metal spur (or just get the metal spur and extra clutch plates needed to convert your 3s slipper), lower kv motor (2200-2400kv), and run a 12T-15T sized pinion no larger.

The 4s outcasts has plastic drive shafts so it can work but it’s all about having the slipper set right.

The 4s shafts are exactly the same as the 3s but just longer and you can't run then without also running 4s arms, 4s hubs, and 4s hexes which also means switching to 17mm hex sized wheels or swapping your 3s axle shafts to the 4s axles but I am not sure if that will work with the 4s hubs.

 

[Nicholas yambao]

Definitely do the metal diffs.

 

[Red92rs]

Just pull up the exploded view of the 4s Kraton. Everything will interchange. I agree what was said earlier though, the slipper on 4s seems to be a poor design choice. This thing on 3s is already beast mode!

 

[bigrockva]

I may just keep it at 3s and keep beefing it up lol.

 

[bcusitsjeff]

Just pull up the exploded view of the 4s Kraton. Everything will interchange. I agree what was said earlier though, the slipper on 4s seems to be a poor design choice. This thing on 3s is already beast mode!

Good to know. So I can swap arms and driveshafts onto the Big Rock from the Kraton 4s?

 

[ph47mf]

I'm not being funny but with all of those upgrades you may as well buy a 6s.

 

[arrmadillo]

To me it just doesn't make sense to dump all that money in a 3S truck just to run 4S. Moe RC just put a Arrma 6S blx system in a new V3 Bigrock and it's absolutely ballistic.

 

[Yonic]

I run my Typhon 3s on 4s most of the time with everything stock other than the electronics. it holds up perfectly fine, but maybe the slightly heavier big rock wheels change the equation?

I have no special issues on the Typhon with stock driveshafts. just make sure your slipper is set correctly.

 

[Red92rs]

Good to know. So I can swap arms and driveshafts onto the Big Rock from the Kraton 4s?

Yes everything will interchange as they are the same skateboard chassis underneath. The brace is the major addition (outside of drive train) that is different between 3s and 4s

 

[BashOfWar]

Just basically throw all the 4s outcast/kraton parts on the 3s frame.
Good to go.