New on Two Wheels
The world of RC vehicles is vast and varied, with models designed to replicate every type of real-world vehicle, from cars and trucks to planes and boats. But there’s one type of vehicle that’s been largely overlooked in the RC world until now: the motocross bike. Enter the Losi Promoto-MX, a groundbreaking RC motocross model that’s set to create a new niche in off-road RC.
Horizon Hobby launched this bike under the Losi brand at the start of July 2023. It caused quite a stir, as while bikes have been around for some years now, durability or performance or realism or size have all been challenges to the existing models from other manufacturers. To see one that is apparently stable off-road, with a realistic and bendy rider, whilst looking great and pulling stunts – well, that’s something new! Then consider the size of the thing and you have a compelling new toy to seriously consider!
The Losi Promoto-MX isn’t just another RC motorcycle. There are some good models around already, though they’re mainly on-road. The Losi is something different. It’s a meticulously designed, ultra-realistic 1/4 scale motocross bike that captures the thrill of riding a full-size bike with unprecedented accuracy – even if the rider’s rear doesn’t ever leave the saddle!
It’s clear the Losi team has gone above and beyond to reproduce true dirt bike performance. The realism of the Promoto-MX runs deeper than its faithfully detailed looks, too. Consider the narrow frame, the rider with authentic riding gear, and the officially licensed graphics. More important is the accurate performance, accomplished through a unique hybrid of mechanical and electronic technology that appears to let you run an RC bike like never before. More on that below; it is really quite impressive and it’s exciting to share if you’re new to this model!
Losi teamed up with the engineers at Spektrum RC to reinvent stabilization technologies for a surface vehicle that requires balance to work. The Spektrum MS6X continuously calculates the bike’s positioning relative to gravity, taking into account the inputs from the transmitter. There’s a 2700kv motor driving a 22,000rpm gyroscopic wheel as part of this system. The MS6X feeds outputs to gyro, throttle and steering that give realistic and predictable handling to the ‘driver’ at the radio. The more I think about what they’ve done here, the more impressed I am – this thing is a marvel of modern technology.
But then, it gets better: stopping distance was cut in half by complimenting the traditional rear-wheel braking (ESC+motor) with a cable-driven front disc & caliper system. Just as on a real bike, stopping with both wheels is far superior to just the rear wheel, and marginally better than just using the front. (Of course, you can get lost in the techincal side of motorcycle handling and which brake to use when, but in an RC model, we don’t have to get so sidetracked!) This new technology works behind the scenes to give the Promoto-MX performance superior to any previous RC motorcycle.
Durability and Protection
Knowing the Promoto-MX would exceed eight pounds, the Losi team over-engineered critical areas to give the bike the extra support needed to withstand hard-hitting dirt bike action. The innovative front crash structure is rigid during normal running, but absorbs front impacts by compressing until the front tire bottoms into the chassis frame. That protects the front fork tubes from bending, keeping them safe and true. Included skid plates guard critical components from rocks and debris, and a twin aluminum plate chassis shields all of the bike’s electronics.
Suspension Like No Other
No other RC product on the market has a suspension package like the Promoto-MX. Losi studied the suspension geometry and technology of full-size motorcycles to give it the same handling characteristics. The front suspension takes a unique approach to RC shocks with a front fork and internal dampener and spring. It’s adjustable, rebuildable, and looks like the real deal. The Promoto-MX also has a rising rate rear suspension, just like a real motorcycle. It starts soft around ride height but stiffens as the shock goes deeper into its travel, keeping the bike from bottoming out on flat landings.
Losi Promoto-MX Powertrain
The heart of the Promoto-MX powertrain is a robust Spektrum Smart Brushless System, featuring a 3800Kv 4-pole brushless motor and 85A Smart ESC. This is a sensored system that will get you moving out of the gate hot, with enough torque to clear large triples and hit 40+ mph top speeds on a 2S LiPo battery. The durable drivetrain is true to scale, with chain drive that lets your rear tire rip whenever you’re ready to send it!
Realism in a Motorcycle
The Losi Promoto-MX RC motorcycle sets itself apart from every other remote control motorcycle and dirt bike with its scale details, authentic control, and realistic powertrain with disc brakes and chain drive. The gyroscopic force of the flywheel partnered with the new MS6X stabilizing technology from Spektrum deliver the stability of anything on two wheels, all in a 1:4 scale RC dirt bike package.
Something that maybe wasn’t practical to produce at scale until recent years, the Promoto-MX features a firm but flexible model human rider. The head jiggles over the bumps, there’s a bum on the saddle and the protective gear matches the smart livery of the bike, in all three colorful designs. The only thing you’ll miss seeing is the rider standing on the pegs when the going gets rough or the air gets big. Perhaps that’s one area modders can work on as this niche becomes more established. Today more than ever before, the potential for such a mod is there. We have the technology! …Probably!
Mastering RC Motocross
Maneuvering a motorcross bike around obstacles, carving precise turns on the dirt or popping wheelies over berms are challenging enough on a real bike. When you consider that many RC cars are basically just suspension, steering and motor in a chassis, and then what is involved when you cut the number of wheels in half, making a stable and drivable model seems like a tall order. We know that keeping balance is easy enough for a bike, as long as that rear wheel is spinning. But what about stability in turns and in the air? The Losi Promoto-MX RC motorcycle has the stability you need to perform those stunts and tackle the tight turns thanks to an onboard gyro – but it doesn’t do everything, and has been designed in a way to be complimentary to the drive whilst still leaving enough challenge on the table for it to stay interesting! Working to improve your control and adding new skills to your repertoire should keep you coming back to the bike for more!
Losi Promoto MX Specs
- Model Scale: 1/4
- Ground Clearance: 2.9 in (73mm)
- Product Length: 20.2″ (513 mm)
- Product Width: 10.8″ (274 mm)
- Product Height: 17.3″ (439 mm)
- Product Weight: 123.5oz (3500g)
- Battery: Sold Separately (or in bundle)
- Connector Type: IC5
Motor & Gears
- Drivetrain: 1WD
- Motor Size: 540
- Motor Type: 3800kv ‘Smart Brushless’ System
- Final Drive Ratio: 12.0:1
- Internal Gear Ratio: 4.8:1
- Spur Gear: 50T
- Pinion: 20T
- Ball Bearings: Full Ball Bearings
- Gear Pitch: 32P
Wheels & Suspension
- Suspension: Front Fork, Rising Rate Rear Suspension
- Shock Type: 16mm Big Bore Aluminum Shock
- Wheel Width: Front – 1.1 in (28mm), Rear – 1.4 in (36.3mm)
- Tire Compound: 65S
- Front Brakes: Cable-Driven Piston/Caliper/Rotor
- Rear Brakes: Motor Braking
- Tire Tread: Dunlop Geomax MX53
Chassis & Tech
- Chassis: 3mm Aluminum Plate
- Body: Color Molded Panels with Wrap Graphics
- Speed Control: Included
- Charger: Sold Separately
- Receiver: Included
- Radio: Included
- Technology: AVC and SMART, MS6X
- Power Type: Electric
- Servos: Included
The Losi Promoto-MX will be a game-changer in the world of off-road RC. It seems like one of those products that creates its own niche of vehicle upon release, in the same way the Axial SCX6 did, or the Traxxas TRX6, for example. Its unique design, innovative features, and high-performance capabilities make it a must-have for any RC enthusiast. I understand this model will be broadly available for sale at the end of August 2023. Whether you’re a seasoned pro or a beginner, the Promoto-MX is sure to provide hours of thrilling off-road racing action. Snap one up when they’re out – I know I will!
Photo credit: HorizonHobby.com
Craig has been into radio control since the 90s and into RC crawling since about 2010, when a Losi MRC started the obsession! Now it's all rocks this and crawl that and upgrade all the things! ...You know how it is, right? Welcome home 🙂