Lower CG in TRX-4

[Jerold]

I have a TRX-4 (2-speed and lockers) and want to lower the CG.

My current setup is factory frame & links (except drag link). Springs are all the way down.

Front

• Brass diff cover
• Brass C-Hubs
• Brass portal cover
• Brass wheel inserts

Rear

• Brass diff cover
• Brass inner portals

I run a small 2200 mah 3S up front (139g). The weight is about 58/42 front/rear and a total weight of 3.6 Kg (<8lbs).

Over all I'm pretty happy with the weight distribution (it climbs) but the side hill could be better and thinking the CG might help. I could mess with the foams but they aren't slide as much as the truck tips.

Some thoughts.

• Use the center battery tray, it will lower the CG a tiny bit, but that throws the weight distribution off 54/46.
• Lay down the shocks a bit more to lower the chassis
• Remove the springs and run 100% droop.
• Start removing the inner fenders and replace with shock towers.

Any thoughts on what else can I do to lower the CG? Or is any of this bogus?

 

[WickedFog]

I have a TRX-4 (2-speed and lockers) and want to lower the CG.

My current setup is factory frame & links (except drag link). Springs are all the way down.

Front

• Brass diff cover
• Brass C-Hubs
• Brass portal cover
• Brass wheel inserts

Rear

• Brass diff cover
• Brass inner portals

I run a small 2200 mah 3S up front (139g). The weight is about 58/42 front/rear and a total weight of 3.6 Kg (<8lbs).

Over all I'm pretty happy with the weight distribution (it climbs) but the side hill could be better and thinking the CG might help. I could mess with the foams but they aren't slide as much as the truck tips.

Some thoughts.

• Use the center battery tray, it will lower the CG a tiny bit, but that throws the weight distribution off 54/46.
• Lay down the shocks a bit more to lower the chassis
• Remove the springs and run 100% droop.
• Start removing the inner fenders and replace with shock towers.

Any thoughts on what else can I do to lower the CG? Or is any of this bogus?

I am not a big crawler guy, but I uderstand how it all works. On rock crawlers, I don't see any need for any upward travel of the suspension. Having soft fluffy tires is more than enough to soften the bumps. So full droop would make the most sense to me.

If you can find springs that allow the truck to sit at or near full droop, that to me would be better than no springs. For example: if the rear of the truck is situated in a way to not let the front of the body fall to follow the front tire down into a crevice or something, without a spring in there, that front wheel will only get traction from the unsprung weight of the front axle. Having a spring in there will at least add some sprung weight of the chassis help to keep traction on the front tire.

Another option is hub extenders, but the drawback of those is your front wheels will turn a bigger arc. This will add scrub steer and possibly cause the front tires to rub the body. But they will effectively help with side hilling by giving the truck a wider stance.

Our little SCX24 C10 runs pretty close to full droop and I love the way it looks driving in this.

And quite funny, because the van body on this is heavier, yet this truck still has some bounce to it. Our C10 does much better than this of course.

 

[Jerold]

Another option is hub extenders

I wish you could have seen me snap my finger and say your right. I'm running Injora wheels and they hub options like the SLW hubs. I might even have some. There are also brass options which would add more rotational mass, but it's tight with the axle so the extra strain is minimal.

 

[islandlife]

You can also run a small spring (pen spring, etc) under the piston inside the shock to suck down the shock. I like the way this handles, if set up right, better than no spring/full droop.
You could also switch to spooled diffs, and get rid of the locker servos, and all the weight that goes with them.
Also, ditch inner fenders for shock towers, less weight as well

 

[nino]

It's a great truck out of the box but it is tall and heavy. Short of swapping to a LCG chassis you've done pretty much all you can. I run brass knuckles and portals, that's it. Even my wheels are plastic. 2200 3s battery on one side, esc on the other. Cherokee body trimmed to hell and back, mounted as low as possible, no bumpers or sliders.