ARRMA Big Rock RC Monster Truck Review: Should You Buy it?

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RCHobby Lab’s Author: Daniel Henderson
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Reviewed by Kristen Ward
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Reviewed by Kristen Ward

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ARRMA have just released their eagerly anticipated 1/7 scale BIG ROCK 6S bash truck, and it’s fair to say it made quite the entrance on the RC scene. This beast of an RC car turns heads with its huge size, aggressive styling and eye-watering price tag.

But is the Big Rock 6S worth shelling out for?

I take an in-depth look at the specs, performance and value proposition of this monster truck to find out.

Overview and Unboxing

As soon as you lay eyes on the BIG ROCK 6S, there’s no mistaking it’s intention – this truck means business. Styled like a souped up monster truck, the Big Rock cuts an imposing figure with its giant tires, exposed chassis and flared wheel arches.

Available in stealthy gunmetal grey (as tested here) or bright red and white color schemes, there’s no danger of the Big Rock blending into the background! I’m a big fan of the gunmetal look which compliments the exposed chassis components nicely.

The bodyshell itself is a work of art, with exceptional attention to detail. Elements like the front grille, molded headlights, windscreen wipers and wing mirrors add terrific scale realism. Out back, the truck bed, roof skids and rear wings continue the spectacular styling. It’s easily one of the best looking RC bodies I’ve come across.

Durable Design

As well as looking great, the Big Rock bodyshell seems highly durable. It’s made from firm, flexible plastic that should be able to take plenty of bash damage. The wing mirrors do worry me slightly as they could be prone to snapping off, but thankfully they fold in to some degree.

Accessing the chassis is nice and easy thanks to a clever clipless body mounting design. Simply unclip the two rear body posts, then slide the whole shell forward to remove it. Replacing the body can easily be done single handed too.

Packed Box Contents

Inside the box is everything you need get bashing, minus batteries and charger. Alongside the pre-built RTR truck itself, highlights include:

  • SPEKTRUM DX3 3-channel transmitter
  • Comprehensive toolkit including cross wrench and shock spanners
  • Printed manual
  • Decal sheet
  • Replacement dog bones, shock parts and rod ends
  • Optional high speed pinion gear

The included SPEKTRUM DX3 transmitter feels decent quality, with throttle limiting functions, dual rate adjustment and all the basic trims. It runs on 4x AA batteries which ARE included in the box.

One negative for some will be the lack of battery and charger. So factor these into your budget if you don’t already own compatible 6S packs and charger. It’s also worth noting the BIG ROCK runs IC5 battery connectors, which are still reasonably uncommon in RC.

Detailed Overview of the Truck

With the bodyshell removed, the extent of the Big Rock’s basher pedigree quickly becomes clear. The chassis and drivetrain components are hugely over-engineered to cope with extreme 6S power. Highlights of the heavy duty spec include:

Beefy Suspension Arms

The suspension geometry features thick composite plastic arms with strong caster blocks/hub carriers. These control opposite wheel travel and house the dog bone drive shafts.

Despite their size, the arms have plenty of articulation thanks to metal pivot balls. The arms mount to durable metal shock towers front and rear.

Smooth Oil Filled Shocks

Big Bore aluminum shocks provide 20mm of oil damped travel. These scale units are beautifully made, with gold anodized bodies, adjustment collars for ride height and smooth operation. Out of the box the damping feels spot on for big jumps and controlling landings.

Multi-Link Rear End

A pivoting rear pumpkin style differential transfers power to the back wheels through dog bone drive shafts. This sits nestled between rear caster blocks, alloy rear arms and a smart looking drag link. Expect excellent articulation and stability from this robust rear end.

Multi Dog Bone Drivetrain

Dog bones handle drivetrain duties front and rear – delivering smooth operation and reduced strain over single piece drive shafts thanks to their slight articulation. The front bones are metal, with plastic rear units.

Centering the front diffs is a durable steel front brace. It holds everything rigid and true while allowing chassis flex. Out back, a plastic brace ties the rear gearbox and shock tower together.

Sway Bars, Skids and Guards

Further enhancing control are adjustable front and rear sway bars. these tame chassis roll in corners while allowing free suspension movement otherwise.

Underbody protection comes from foam skid plates front and rear plus plastic guards shielding the lower suspension arms from debris. Integral front and rear bumpers provide crunchy crash protection too.

Spektrum Firma 160 ESC and 2050kV motor

Electronic speed control duties are ably managed by a SPEKTRUM FIRMA 160 Amp brushless ESC. This sensored unit provides smooth, strong power control to the 2050kV brushless motor. Cooling comes from a built-in fan and neat heat sink.

In testing this ESC/motor combo has impressed me with its sheer grunt and reliability, even on 6S power. The throttle feel is beautifully smooth too, great for learning RC control. No wonder Arrma use this setup across several models.

Waterproof Components

Like all late model Arrmas, the Big Rock backs up its bash truck looks with waterproof electronics throughout. The servo, receiver box and ESC are all fully sealed, allowing driving through puddles, mud and over wet grass with confidence.

Set Up Tips

Before hitting the bash spot, it’s worth double checking a few areas of the truck:

  • Tire pressures – Run the tires at around 20PSI to start, adjusting pressure depending on surface. Harder surfaces may allow slightly lower pressures. Too high pressures reduce grip, too low pressures make the ride bouncy.
  • Wheel nuts – Loosening then re-tightening the wheels helps seat the locks. Check tightness before each run.
  • ECS Settings – I’d recommend limiting throttle dual rate to 75% initially, until you become familiar with the power output. If temps get very high, dial in more ESC punch control.
  • Receiver binding – Make sure to correctly bind the receiver to your transmitter before running the truck. Binding locks their communication signal together.
  • Check screw tightness – Vibration can loosen chassis screws surprisingly quickly. Check nothing has worked loose after initial runs.

Driving Impressions

Even with tires at stock pressure and the ESC in training mode, the BIG ROCK feels startlingly quick off the mark. Clearly that 2050kV motor and 160A ESC have some serious punch, because wheel spin is almost instant.

Yet surprisingly once moving, traction levels seem really good. The tyres have quite a hard rubber compound which bites better than expected on loose surfaces. On tarmac they can struggle for grip under power, but handle well at speed in corners.

I’ll admit I expected body roll to be pretty wild on such a tall, heavy truck. But the combination of wide track, low center of gravity, stiff suspension and sway bars keeps things impressively flat.

Jumping is where that plush suspension travel really helps though. Landings feel well cushioned as the shocks soak up small bumps and hard impacts alike. I’m also impressed how rarely the chassis bottoms out – those droop settings seem on point.

Brushless Power!

The excellent throttle control encourages driving the Big Rock deep into corners, then lighting up the tires on exit. Serious mechanical grip combines with the ESC’s smooth power delivery for responsive acceleration even from low revs. Whipping wild power slides on demand builds huge confidence.

And make no mistake, the outright speed available truly transforms this giant truck’s character once you switch to 6S power. Where traction permits you can enjoy tire shredding velocity thanks to the 40+mph top speed. Gear it up further and even 50mph+ is possible!

Yet the Big Rock seems surprisingly stable at speed too. That stiff chassis keeps things locked down, helped by firm suspension and the low ride height. Even hitting big jumps flat out poses no major issues as long as you land smoothly.

Bash Test Conclusions

So going back to my original question – is the BIG ROCK 6S worth its hefty price tag? Well in terms of performance and fun factor, I’d say an emphatic yes. Beneath its stunning looks lies a thoroughly engineered, massively quick and surprisingly refined bash truck.

But there’s no escaping the high cost to buy in to that experience, especially here in the UK. At full RRP, the Big Rock represents a serious investment that could prove difficult to justify for some enthusiasts. And it’s important to remember the ongoing running costs too, what with needing multiple 6S battery packs to unleash its full potential.

Yet for hardcore RC bash fans with the funds available, I’ve little doubt they’ll appreciate everything the Big Rock 6S brings to the table. Because ultimately, this is one of the most enjoyable RTR bash trucks I’ve ever tested.

Pros and Cons


  • Exciting styling that turns heads
  • Fantastic performance on 6S
  • Beefy chassis handles huge jumps and drops
  • Smooth power and handling balance
  • Quality electronics and components
  • Great aftermarket support


  • Steep initial purchase cost
  • IC5 battery connector could limit pack choice initially
  • Very quick, may prove too much truck for less experienced drivers
  • High maintenance (frequent shock oil changes etc)

Upgrades and Modifications

Whilst the out-of-box specification is extremely capable, enthusiasts may consider these worthwhile upgrades:

  • Stronger metal rear dog bones – better cope with 6S power levels
  • RPM front A arms – almost indestructible protection
  • Aluminium steering knuckles – extra durability
  • Wheelie bar – help tame wheelies from standstill
  • Body protectors – guard fragile panels against scrapes
  • LED light kit – night runs look fantastic
  • Gearing change – smaller pinion for more wheel speed

As always with heavily modified RCs, double check any changes don’t push stresses beyond component limits.

Final Thoughts

Few ready-to-run RC cars make an entrance quite like the BIG ROCK 6S. This monster machine immediately captures attention with imposing size and flamboyant bodywork – then blows your socks off with outrageous power.

Make no mistake, blasting around on 6S with the throttle pinned takes some skill. Yet ARRMA have struck an excellent balance by providing a surprisingly forgiving truck too. It flies high, lands softly and rips epic doughnuts like a boss.

Factor in the robust chassis and high quality components throughout and only one conclusion seems fitting. The BIG ROCK 6S stands as possibly the ultimate no compromises basher for intermediate+ drivers.

Beg, borrow or save your dollars, then go enjoy living large with ARRMA’s outrageous new toy!

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Written By Daniel Henderson

My name is Daniel Henderson and I'm an avid FPV pilot and videographer. I've been flying quadcopters for over 5 years and have tried just about every drone and FPV product on the market. When not flying quads, you can find me mountain biking, snowboarding, or planning my next travel adventure.

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