I've been excited to get my hands on the ARRMA Nero 6S monster truck ($700) ever since it was released a few months ago. First of all, being a 1/8-scale vehicle, the Nero is bigger than any of my previous RC ground-pounders. With a large brushless motor and 6-cell LiPo battery, the Nero also promised to be much more powerful than anything I'd ever driven.
Size and power are certainly alluring, but the real reason I was intrigued by the Nero had to do with a feature called Diff Brain (a version of the Nero without Diff Brain is also available). This package provides the ability to lock and unlock the Nero's differentials on the fly. I've never seen such a feature on any RC vehicle before. I had no idea if this was a useful capability or just marketing hype. I couldn't wait to test it myself.
Nero 6S Overview
The Nero is pre-built and comes equipped with everything except batteries. You'll need two 3-cell LiPo batteries of about 5000mAh capacity. I used a pair of Duratrax Onyx 3S-5400mAh packs. You'll also want to make sure that your batteries have a high discharge capability, since the Nero will pull a lot of amps under hard acceleration. The 50C discharge rating for these Onyx units seems to be more than adequate.
The difference between a common RC truck in 1/10-scale and one in 1/8-scale doesn't seem like it would be that significant. After all, the physical dimensions aren't that far apart. I soon found that assumption to be false. The Nero has more than double the mass and power of most of my 1/10-scale rides. Moving up to a 1/8-scale vehicle brings a whole new level of performance and significantly beefier components. You'll also need to be prepared for increased maintenance overhead.
Two red-anodized aluminum plates comprise the backbone of the Nero's chassis. All of the other chassis components are made of black nylon. The suspension is damped by four large, oil-filled shocks. The shocks are in a horizontal orientation with bellcranks and pushrods connecting them to the suspension arms.