Ep.32 TRX-4M 2-Speed Beetle Build & Crawl – DBR Chassis, Meus Isokinetic Axles, Furitek Brushless

I've always wanted to build a beetle rc crawler. And I chose to build it with the TRX-4M platform because I was also curious about the two-speed transmission of Meus Racing. The idea of having that kind of versatility interests me – a beetle car that can both crawl and zoom over obstacles.

Build specs:

• Buggin' Out Kit by DBR Chassis: Gila Monster aluminum chassis, 3D printed cage (old version), chassis braces, and raw body. I sanded and painted the cage with holographic paint. I gave the body a sunroof and half-doors to showcase the gearbox and cage.

• Isokinetic axles (52º steering angle) and 2-speed transmission by ‪@meusracing‬: 56:6:1 low gear (slower than Traxxas crawler gears), 15:7:1 high gear (faster than stock gears)

• Micro Komodo and Lizard Pro by ‪@FuritekUSA‬

• 59mm shocks by HobbyPark

• 64mm tires and K10 high trail links by ‪@INJORA‬ (to shift more weight to the front)

• Slymeballz tire inserts by ‪@FlubRC‬

• OGRC solid wheels

The two biggest challenges of this build were (1) mounting the battery, and (2) mounting the body rear. I tried a couple of things, but these are the most viable, most low CG, and most ergonomic solutions I had:

(1) With more than half of the cabin occupied by the transmission case, plus a servo arm sticking out behind it, there wasn’t any space left for a proper battery tray. So I modified the rear chassis brace to hold a modified battery tray with the same pair of magnets that will hold the hinged body mount. When the body hinge is attached, there are a total of six magnets that are aligned, producing enough force to hold the battery weight. The chassis brace was mounted 2 slots higher to make space for the links. There’s but a hairline gap left at full compression of the rear shocks.

(2) The body hinge was from my SCX24 Deadbolt, which I shortened to match the cage height and then fitted with magnets underneath. The hinge doesn’t swing all the way back but it leaves enough opening to turn on/off the ESC easily.

This build had a couple of other challenges, like:

• the pinion gear screw hits of the Micro Komodo hits the first cog of the transmission, therefore preventing the gears to turn. At first, I used brass spacers for mounting to pull back the position of the brushless motor. This worked but it left the gearbox susceptible to dirt/sand. So I just reversed the pinion gear, problem solved.

• the brushless motor is mounted higher than stock on the 2-speed gearbox. I modified the front chassis brace to make room for the out-runner motor

• to mount the headlights, I had to make an outer ring that I attached to the body interior

Then I flew to S.Korea (Seoul and Busan) for a test crawl., I'm just glad that all the effort (and expenses) were worth it in the end. This crawler is so versatile across different terrains. It crawls elegantly. It's really good with downhilling and sidehilling. It can climb steep angles despite its heavy weight. And it looks really good, too 🤘🏼

My only gripe is the torque twist, which is common to all TRX-4Ms. I guess there are some things that money or creativity cannot solve.

#rccrawler #rctruck #rc4x4 #rcoffroad #traxxas #trx4m #vwbeetle #buggyrc #meusracing #furitek