The HPI Baja 5b Flux RTR Takes the Stage: A New Classic!

There’s no such thing as an HPI Racing fan that hasn’t heard of the Baja 5b. Released in May 2006, it was a game-changer in the US market and a mover and shaker worldwide, helping to popularise big buggies in a big way. The 1/5th scale size is now much more of a key player than it used to be – and that’s partly thanks to the HPI Baja 5b. A couple of new versions and releases down the line, and its place in RC history seems well and truly confirmed.

But, for a long time, there was something missing in this illustrious product family. Great as it was for gas/oil mix racers, there was no electric motor-powered version to match. Brushless motor specialists were unable to benefit from all of the great (transferable) advances that had made the original Baja 5b models so popular – not to mention the lower price tag that tends to come with HPI’s brushless Flux models. How unfair is that?

Enter the Baja 5b Flux. Although it was only released relatively recently (in 2012), this model – the only brushless HPI Baja model to date – is already showing all the hallmarks of a beloved classic-to-be. Unleashed against the backdrop of its predecessors’ fame and popularity, it was set up for success – and the machine itself hasn’t disappointed.


Packed with all the great performance features and serious power that we have come to expect from HPI’s vehicles, it’s a hefty machine capable of incredible top-speeds for its size. Using the pre-installed Castle Creations 2028 780Kv brushless electric motor and a 8S 33.6V Li-Po battery pack, it can hit up to 60 mph (97 kph) in spite of its 10kg bulk, putting almost 10HP at your disposal instantly. (It can also run up to 40 mph or 64 kph using a 6S battery, with which it is also compatible.) It might not look that fast at this size, but that’s a fine amount of power for a 1/5 scale vehicle to have up its sleeve.

And, typically, it’s not just the statement statistics that impress, but the attention to detail behind them. The brushless motor, for example, is kitted out with a series of great extras such as super-thick wires, gold-plated connectors and specialised cooling fins that help it to achieve not only its impressive power and torque, but also enhanced durability, efficiency and long-term performance. And you could look at almost any component of the Baja 5B Flux and find a similar level of detailed, expert workmanship.

A particular stand-out feature of the Baja 5B Flux – and one that you won’t find on its fuelie counterparts – is the electronic speed control, a heavy duty Mamba XL2, also by Castle Creations. New to the HPI Baja range with the arrival of the 5B Flux, it is a worthy match for the size and weight of an HPI Baja vehicle. But the Mamba has even more up its sleeve; as well as being fully programmable, it is also capable of data logging, allowing 5B Flux owners to measure parameters such as battery volts/ripple voltage, amp draw, motor rpm and even the temperature of the controller itself. It’s an excellent diagnostic tool built into the brushless set-up, helping to set the HPI Baja 5B Flux apart from other brushless vehicles – and its Baja predecessors.

The Baja 5B Flux is also commented on for bringing its own new look to the range with a a Flux-specific body – shaped, patterned and coloured in a distinct and original way. Many have applauded it for being more tasteful that previous HPI Baja stock design schemes, showing off more muted or neutral colours that are better suited to its price range. The smooth, flowing, symmetrical body lines – impossible on fuelie vehicles due to the need for a fuel cap entry slot breaking through the shell – and all-over gunmental anodizing also give the Flux version of the HPI Baja 5B a distinct air of class. (Though if you prefer things to be a bit jazzier, don’t despair – original 5B coloured parts fit a treat.)

Look at the other aspects of the vehicle, however, and it soon becomes clear that the Baja 5B Flux owes as much to the Baja 5SC as it does the original fuelie Baja 5B or its own R&D. Many key features of the 5B Flux’s drivetrain have been copied straight from the 5SC, including the extra-thick 9mm dogbones that formed part of a major upgrade of the 5SC’s durability. The drive shafts, diff shafts, drive axles and mud-beating ‘rubber boots’ are also all the same as on the upgraded short course model, bringing all of those advances in HPI’s design and research to the Baja 5B Flux. And in this case, we’re glad there’s nothing too original been done – after all, if it’s not broken, then don’t fix it!

The other hardcore durability features – which also owe a lot to the rest of the HPI Baja range – include an all-metal gear transmission, long travel suspension, VVC/HD shock absorbers and HPI’s unique Viscous Torque Differential. The damper units used by the shock absorbers are, in fact, the exact same units as those used in the Baja 5T and the Baja SS, while the Viscous Torque Differential is a classic HPI oil-filled gear differential with tough metal gears and an aluminium alloy housing. The extra-large metal-geared SFL-11MG high torque steering servo (featuring an aluminium steering arm and Cam type servo saver) has also featured in the 5SC and SS models of the HPI Baja range.

All in all, this makes the HPI 5B Baja Flux a vehicle that owes a lot to its background, but still brings fresh new approaches with dazzling quality to the HPI Baja scene. Although it’s still young, it’s gaining ground fast and has all the makings of a classic vehicle. Whether it’s on your radar as a potential purchase or just out of interest, make sure that it stays there!

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