RocHobby Ridge Racer U4: Massive 1/7-Scale Ultra4 RC Action

If you’re looking to conquer rough terrain in true off-road style, the new RocHobby Ridge Racer U4 might be your next beast of a radio control machine. Offered by FMS and modeled after a Ford Bronco Ultra4 rig, this 1/7-scale RC crawler/desert racer hybrid is built for serious performance. It comes brushless-ready, runs on 6S LiPo power, and arrives equipped with rugged details, scale features, and trail-taming hardware throughout.

PRODUCT FEATURED
ROCHobby Ridge Racer U4
By: FMS Model
Kit Type: Ready To Run 1/7 Electric 4×4 Truck
Part Number: ROC10701RSBU
Price: $549.99
Buy: https://bit.ly/49Ja356
Requires: Two 2S or Two 3S LiPo Batteries, charger and four AA’s
Visit FMS: https://bit.ly/3UWpY8t
Suggested Gear:
Battery Options- https://alnk.to/7BgpHBY
Hitec RDX2 800 Charger- https://alnk.to/biukiJ9

In this review, we’ll break down all the big features of the Ridge Racer U4 so you can decide if this large-scale 4WD rig belongs in your RC garage. We’ll cover the Body, Chassis, Steering, Suspension, Drivetrain, and Electronics. Whether you’re into scale realism, high-speed desert bashing, or just want something that turns heads, read on.

Body: Scale Detail Meets Functionality
The Ridge Racer U4 immediately catches your eye with its Ford Bronco-inspired body, styled like an Ultra4 4400 race truck. It features a one-piece Lexan shell secured to an internal roll cage for structural rigidity. A tilt-up mechanism gives you access to the battery without removing the body completely, although full removal requires disconnecting the sway bar and limiting straps in the rear.

Scale enthusiasts will appreciate touches like the working LED light bars, detailed Lexan interior, and a molded driver helmet. A full-size spare tire mounts to the rear, reinforcing the Ultra4 look. The rear cage locks into the body for a snug fit, helping eliminate awkward flexing in the body panels.

Chassis: Built for Abuse
Under the body, the Ridge Racer’s layout follows the typical desert racer platform, similar to models like the Losi Baja Rey or Traxxas UDR. However, Rock Hobby steps it up with a 3mm thick aluminum chassis plate, aluminum bracing front and rear, and a generous battery tray that accommodates stacked 3S packs for 6S running.

Everything is countersunk and reinforced, including aluminum top plates and heavy-duty brace plates. There’s even a metal center differential housing. One downside: the factory hardware can be overtightened — one screw had to be drilled out during disassembly. That said, the platform overall is clean, accessible, and seemingly easy to wrench on.

Steering: Strong, but Watch for Flex
Steering duties are handled by a 30kg high-torque servo mounted up front using simple vertical posts. It connects to a dual bellcrank steering system with a built-in servo saver and adjustable tie rods.

While the servo is huge, it’s mounted with only two 2mm screws, which allowed for a bit of flex until tightened. The system offers a wide steering angle thanks to CV-style front driveshafts, and you can convert to a standard-size servo with the included hardware if desired.

Suspension, Wheels & Tires: Trail-Tuned Articulation
The Ridge Racer U4 sports an independent front suspension and a solid rear axle with trailing arms, mimicking real-world Ultra4 setups. Each corner features a dual-shock arrangement — a primary oil-filled shock with threaded bodies and adjustable collars, and a secondary slave shock for added damping.

The arms have good sweep and clearance, and the sway bars front and rear help with stability. The rear suspension includes massive metal upper links, composite trailing arms, and working limiting straps. The only concern is the small tab securing the rear axle pivot, which may be a potential weak point under extreme stress.

The wheels ride on 17mm hexes and wear aggressive desert-style tires with a hard compound and firm inserts. While the compound is durable, it might lack bite on some surfaces — more on that in the performance review. However, they look the part and should do well in sand or hardpack.

 

Drivetrain: Heavy-Duty Power Delivery
This 4WD monster uses front, center, and rear gear differentials — all with metal gears. The center diff is especially noteworthy, housed in machined aluminum to handle the heat of 6S power. A metal spur gear, sealed bearings, and spiral-cut gears all point to a durable, thought-out design.

Up front, CV axles provide steering range, while dogbones carry power to the rear. The rear axle assembly is a multi-piece unit with beefy 3mm and 2.5mm screws. A few reports of center diff oil leakage suggest units might have been assembled long ago and should be checked before heavy use — a minor maintenance issue, not a deal breaker.

Electronics: Muscle Where It Counts
The Ridge Racer is loaded with Hobbywing power: a Max8 150A ESC paired with a 4274 1600kV brushless motor. It uses EC5 connectors and supports dual battery leads — no jumper included, so you’ll need two 3S packs for 6S action unless you modify the wiring.

The ESC has a cooling fan and basic programmability. The motor lacks a fan but is secured to a machined aluminum mount integrated with the center diff. A 6-channel receiver sits sealed in a waterproof box, and the radio system — while functional — features a basic plastic wheel and toggle trim settings hidden under a flip-up cover.

 

 

Performance Report: Big Power, Big Fun in the Sand
After waiting out several snowstorms and cold snaps, I finally got the Rock Hobby Ridge Racer U4 into the wild—and it did not disappoint. Testing it on a frigid 30-degree day with soft, loose sand made for a great durability check and a serious challenge for any RC rig. The Ridge Racer handled it with surprising confidence.

Right off the bat, this 6S-powered beast felt immensely powerful. The tires dug into the sand, throwing massive rooster tails and demanding some throttle control during tight turns due to the vehicle’s weight and weight transfer characteristics. It’s definitely a rig that rewards finesse, but when pointed straight, it launches with authority and catches air with ease.

Watching the trailing arm suspension with dual shocks per corner cycle through rough terrain was incredibly satisfying. It soaks up bumps and landings like a true desert racer. However, under hard throttle, I noticed the center differential was a bit light on oil, resulting in excessive power transfer to the front wheels. Heavier center diff fluid would likely improve the driving feel significantly.

As for speed, it’s got solid top-end performance. It feels fast, balanced, and planted, though adding a tooth or two to the pinion could help squeeze more from it on open terrain.

Despite a few tumbles and aggressive runs, the Ridge Racer came away largely unscathed. The hard tires didn’t balloon, but still provided enough grip to hold their line, even in the challenging sand. Some minor rollovers occurred, but the internal cage and rugged body kept everything intact—no major breakages or surprises.

Conclusion: A Serious Desert Rig Worth Considering
The Rock Hobby Ridge Racer U4 was absolutely worth the wait. It delivers a genuine desert truck experience—complete with satisfying suspension action, excellent power, and an aggressive scale appearance. From LED lighting and a full-size spare tire to the functional trailing arm suspension and 6S brushless punch, this truck checks a lot of boxes.

Is it better than the Traxxas UDR or Losi Baja Rey? That depends. The UDR retails around $750 and the Baja Rey closer to $550, but only supports 3S power. In contrast, the Ridge Racer runs 6S and comes in at just around $550, making it an excellent value in the large-scale off-road segment.

There are a few caveats: the center differential oil needs upgrading, the battery tray doesn’t accommodate standard dual 3S 5000mAh packs, and aftermarket support is currently limited compared to the big-name competitors. However, FMS is actively supporting the platform—even offering parts discounts if replacements aren’t available, a major plus for buyers concerned about long-term serviceability.

 

In short, if you’re after an affordable, high-performance, scale-looking desert truck that stands out from the crowd, the Ridge Racer U4 deserves a serious look. It’s fast, fun, and rugged—exactly what you want in a 1/7-scale Ultra4 rig.

 

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