Traxxas TRX4 RE-Build 2.2 Crawler BEAST Before the New Build

by Joey Sacco on July 01, 2019

We have had our TRX4 nearly a year now, and have run it everywhere. Who knows how many miles are on it at the point. We have beat it, put it away wet, and kept going. Aside from the subpar factory electronics that come with these machines, the only breakage has been a portal gear, and it was because we had the slipper clutch cranked down a little too much.

We now take great care in cleaning the rig after a run, and making sure all the moving parts are tight, and not sloppy. We hate being unprecise with our movements due to worn out pivots and linkages. Really, though, the stock links have help up pretty well, and have just replaced our inner C's due to slightly worm bushings. We really cannot complain about the integrity of the components on this platform, even in stock trim.

Our RE-Build will consist of changing a number of things to improve on our truck some more. Prior to the RE-Build, we have done the following modifications:


 - Savox SA1230SG 500oz/in @ 6.0V servo (though we are running it at 7.4!)
 - Metal Beadlocks and Predator compound Proline-Racing BFG Krawler 1.9 tires
 - Dual Stage Crawler Innovations foams, with stiffer foam for the heavier TRX4 platform
 - Large Brass 93g portal covers up front
 - Brass lower spring cups on the shocks
 - Hobbywing QuicRun 10BL60 ESC
 - Tenshock RC906 1750kV 6 Pole Brushless motor
 - Castle 10A BEC
 - Brass lower shock mounts
 - Treal alloy shock mounts front and rear
 - 5mm brass hex wheel spacer
 - Stock shocks. They rule. The only reason to upgrade is to say that you did.

The Savox servo has been on ever since the beginning, since the stock Traxxas unit didn't last more than 20 minutes of light crawling. It's been wet, bashed, overvolted while bound up in the rocks, and has never skipped a beat.

The Proline Racing tires accumulated 5 holes on one side wall after one 3 hour run, on the provided foams. They are sticky, but overall, the durability leaves much to be desired. These should definitely only be used strictly as a competition compound.

The Brass portal covers ( added a bunch of low, unsprung weight, and stability was definitely improved. All the other brass components also added some nice unsprung weight too. The 5mm spacers added some stability, but we did not perform any real-world tests to determine if they, in-fact, helped the rig perform better.

The 10A Castle BEC ( made the servo perform at its highest level, and even allowed to overvolt the steering servo to 7.4V. Who knows how many oz-in it is pushing at this point!

When the stock motor blew up, we decided to try a budget brushless setup, consisting of the Hobbywing 10BL60 ESC and a Tenshock RC906 1750kV 6-pole motor. Surprisingly, after swapping to a 9t motor pinion from the factory 11t, it ran very well, with very little noticable cogging, even in the sketchiest of rocks. Though, it would have been preferred to been able to do so on the stock 11t pinion, but it did show some cogging at slow speed crawling with it.

The Treal aluminum shock mounts have performed well and have good fit and finish. For the price compared to others, it is hard to complain. Though, the front driver side shock mount, that contains the chassis-side panhard mount, has two hole options. The higher hole is not usable, due to interference with the mount and the outer radius of the panhard bar link rod-end.

We played around with a few prototype battery trays, one of which lowered a full size 5500mAh 3S a little bit in the stock location, and another that sat perpendicular to the frame rails, and sat just above the motor. Both showed some improvement in some areas, but not enough to be considered an "upgrade", but more of an "alternative".

OUR GOAL in the RE-Build is to make our TRX4 more capable in the rocks, and be able to still trail ride. We do not care about high speed bashing, because it typically leads to breakages anyway, which is one reason we like crawling over faster bashers. We want to rid the chassis of everything we don;t need, and have only the necessities. The lower the center of gravity the better, and we do not mind sacrificing a little run time to run a smaller battery and reduce the overall center of gravity. If this is the case, though, the body needs to be removable easily for battery changes. We are thinking about switching to 2.2 sized tires to overcome obstacles more easily, and therefore would be easy to toss 1.9 sized tires on, should we want the challenge down the road (or trail). We started with a hard body Injora Cherokee body, which was great as a scale piece, but it was so heavy that it hurt performance, so we will be using a lexan body, and will try and get it as low on the frame as physically possible. This most likely means that the body will need some heavy trimming to accommodate 2.2s stuffed up into it.

Stay tuned for the RE-Build!


Please note, comments must be approved before they are published