4x4

An offroader’s review of the TRAXXAS TRX4 model scale radio control rock crawler

24 Jul 2017

Robert Pepper 4

Wish list

Good though the TRX4 is, it could be even better. For me, the objective is not pure offroad ability, as otherwise you’d just buy a helicopter. Instead, the enjoyment of driving comes from the satisfaction of achievement through your skills and use of your tools. And as a training device, it would be handy to have more even more features to demonstrate to students. So, here’s a wishlist:

• Front and rear lockers individually selectable – at present you have no lockers, front, or front and rear. Also need rear only.
• Centre diff with lock – to allow even tighter turning but also demonstrate to students the effect of locking and unlocking.
• Part time 4WD option – again for training but also it is sometimes handy to spin the back end around in 2WD.
  Swaybars and disconnects – again for training, but this should also help with higher speed runs.
• No need to remove body – why do we need to remove the body to switch the car on, and attach it with four easy-to-lose circlips? Beats me. An external power switch would be a better design.

I am coming at this from a different angle to the RC rockcrawling enthusiasts, who query the need for lockable (as opposed to permanently locked) diffs. They’re right, from a performance point of view, adds weight and complexity. But me, I just love the coolness and the challenge of unlocks vs locked, and I know for sure there’s times when unlocked is better. I can tell you the main reason I bought the TRX4 was the ability to lock the diffs manually.

Here’s the mods I want to make to the little truck:

• Towbar – so we can attach a trailer and demonstrate offroad towing capabilty, and a few things about towing generally. Like trailer sway, difficult to demonstrate without writing off trailers and students which leads to negative feedback.
• Power winch – self explanatory really. Would be very cool.
• Spare wheels and tyres – so, I went out and drove my TRX4 offroad. I come back, and decide I want to play indoors too. Unfortunately…muddy tyres. Damn. Fortunately, I am living with the World’s Most Understanding Woman, so I was able to muddy the floor anyway and then clean it. I guess there are spare wheels and tyres out there, need to take a look.
• Box for it all – very important. I want to take my TRX4 out on lots of 4X4 trips for use when we are camping or just having a break. The cardboard box will not work, but what will is a tough plastic box that also takes the controller, charger, batteries and tools. And doubles as a obstacle to climb over.

TRX4 Specifications

Here’s the specs:

• Length 586mm
• Width 249mm
• Height 291mm
• Wheelbase 324mm  adjustable to 300, 312, 336
• Weight 3.372kg
• Turning circle 980mm (my measurement)
• Steering angle – 45 degrees
• Wading depth – TRAXXAS say it is “fully waterproof”, which cannot be said of the full-sized Defender which is barely mist proof.
• Tyres 118mm tall x 48mm wide
• Wheels 49x26mm
• Ground clearance 47mm (my measurement)
• 41.7 degree approach angle
• 56.97 degree ramp angle
• 56.49 degree departure angle
• Height adjustable shocks. There’s a threaded spring mount you turn to adjust height. Very cool!

Scale equivalents

TRAXXAS claim the TRX4 is 1/10th scale, but if we divide the Defender 110’s wheelbase of 2794mm by the TRX4’s of 324mm we come to a scale of 8.6:1.  The wheelbase can be adjusted to 300mm to get 9.3, but that would be too short for the body.

If the TRX4 was scaled up so its wheelbase was 2794mm, same as the Defender 110 then it would have:

• 40 inch tyres
• a height of 2509mm
• a width of  2147mm
• weight of 2144kg
• ground clearance of 490mm
• an RTI score on a 20 degree ramp of 908, compared to around 580 for a real Defender.

In real life, the TRX4 would look like this:

which is a Defender been modified by Land Rover Special Vehicles to have 38″ tyres, and no doubt a lot of other engineering such as reinforced axles, much lower gear ratios, different suspension and modified steering. No portal axles though.

More information

There’s a bunch of Facebook groups dedicated to the TRX4 already, with varying levels of newbie-tolerance. It’s interesting for me to scroll through the posts – in many respects I feel like a complete newbie, not understanding terms like lexan. I also smile when I see posts about running 1.9s or 2s…refers to tyre diameters. We’d say 33s, 35s or 37s. And sometimes I know more, usually around vehicle dynamics. Either way, it’s a refreshing lesson in just how perplexing a new, jargon-filled hobby can be when your head has 99% enthusiasm and 1% knowledge as opposed to vice-versa. I’ve not found a good intro to RC crawling, but if I do (or can get one written) I’ll post it.

Bottom line

If you enjoy the low range life it’s pretty simple:

TRX4 Photo Gallery