WORDS BY MICHAEL WORTEL PHOTOS CARL HYNDMAN

When Serpent enlisted the expertise of former IFMAR 2WD Buggy World Champion Billy Easton to design a new line of vehicles, expectations were high. The very capable Spyder 2WD SC RM racing platform was the result, and became the jumping-off point for Serpent’s competition 2WD short-course truck, the Spyder SC RM SCT. Offered first as a kit, Serpent now has a ready-to-run version of the truck, which only slightly detunes the DIY model’s specs. The main differences between the SCT SRX-2 and the pro-level kit is a gear diff, slipper clutch, side guard, and a few tuning components. Otherwise, this RTR is the same truck that has found winning success on racetracks around the world. Serpent pairs Spyder’s track-ready features with 3S-capable Dragon-RC brushless gear and electronics, and everything you need to start club racing other than a battery pack is included.

DRAGON-RC BRUSH-LESS SYSTEM

A 2WD SCT like this begs for power, and Serpent delivers by providing a Dragon-RC brushless system. The DX-10 WP 45A speed control is waterproof and sports a cooling fan to help keep temps down so the unit can run efficiently. The speed control can run sensored and sensor-less motors, and it also supports 2S and 3S LiPo battery packs. The low-voltage cutoff automatically detects the number of cells, so you don’t need to adjust the cutoff for different battery packs. The speed control has numerous programmable settings including timing, drag brake, maximum brake, and punch, but you need to purchase an optional programming card to access them. The Dragon-RC 3550kV brushless motor is a basic sensorless 540-size unit, but does score style points with its orange-anodized finish and ribbed can.

Above: The Dragon-RC speed control is 3S-rated and fully programmable—but only with an optional programming card.

Below: Serpent advertises a 3000Kv motor as standard, but has since upgraded the Spyder to a 3550Kv unit. More power is always better!

DIRECT-DRIVE GEARBOX

Surprisingly, the Spyder does not include a slipper clutch, and the spur gear is solidly mounted to the top shaft. The ball differential used on the race version of the truck has been replaced with a bevel gear diff for reduced maintenance, longer wear, and zero chance of slippage. It’s o-ring sealed, so you can tune it by changing the viscosity of the fluid in the differential, and Serpent actually fills the diff with oil instead of just greasing it. Nice! Inside the gearbox, metal top and idler gears spin the plastic diff gear. All-metal is preferred, but if one gear is going to be plastic, it should be the largest one, and that’s the diff. Power makes its final trip to the wheels via high-quality CV-style driveshafts that are fully enclosed by the rear hub bearings to capture the CV’s crosspins without need for setscrews or clips.

Above: The Spyder includes a sealed diff, and Serpent actually makes the effort to fill it with oil—most other brands just slap grease on the gears.

Below: Sorry, no slipper clutch. The omission would make sense for a stock racer, but with a 3550Kv motor and 3S-rated speed control on board, a slipper clutch would be nice.

RIGID ONE-PIECE CHASSIS

The Spyder’s composite plastic chassis is impressively roomy despite its narrow configuration. There is a large gap between the battery and transmission case—a mid-motor conversion could be on the way—but in the meantime allows room for the speed control to be moved behind the battery as weight-distribution tuning option. Even with that extra speed control/future transmission space, there is plenty of room within the battery compartment to move the pack fore and aft. Full-length nerf bars bracket the chassis, and optional lexan plates are offered to fill in their open areas as a means of blocking air from entering the body and “parachuting” the truck over jumps.

Even without top braces, the chassis allows minimal flex—surprising for its long wheelbase.

KIT-QUALITY SUSPENSION The Spyder’s threaded aluminum shocks are a thing of beauty. They are well built and incredibly smooth, and constructed with nutted pistons so there are no e-clips to fool with. From the factory, the shocks are set up “emulsion style” with bleeder screws in the caps and an o-ring to seal them against the shock bodies. If you prefer the feel of a bladder setup, Serpent offers optional caps and bladders. As expected for an RTR based on a competition truck, the suspension is fully-adjustable for camber, caster, toe, Ackerman, wheelbase, and roll center. Cheap turnbuckles are an easy place to save a few bucks on an RTR, but the Spyder gets very nice spring-steel turnbuckles that match the truck’s steel outdrives and CV shafts. High qual stuff. The Dragon-RC transmitter has an LCD screen and more functionality than the average RTR unit. It has 3-channel capabilities, multi-model memory, and a ton of adjustments. Not just trims and steering dual-rate, but also exponential, servo speed and ABS. There’s plenty to work with here.

Left: The Spyder gets much nicer shocks than most RTRs, and includes a full set of dual-cap, threaded-aluminum dampers.

Below: The Spyder’s suspension is fully adjustable and race-ready with spring-steel turnbuckles.

BEHIND THE WHEEL Out of the box, the truck was pretty well dialed-in. The shocks rebounded equally and were the same length side to side. The screws were tight, and the camber and toe angles were consistent on all four counters. The gear mesh, however, was a little tight—not something that a novice would probably notice, but the gear mesh had to be adjusted so there was a little more play between the teeth. Testing began with the 2S LiPo and the SCT SRX-2 had plenty of acceleration—enough to pop a wheelie from a stop. And the gearing seemed perfect, hot off the line, and hitting high speeds in 100-125 feet, about the length of a straightaway on a track. The 3550Kv motor provides ample power, enough to push the Spyder to over 37mph on a 2S LiPo and just shy of 60mph on a 3S MaxAmps pack. Sensorless power systems can have a tendency to lag with aggressive, varying throttle inputs, but the Dragon-RC combo minimized this and was a pleasure to drive. The stock steering servo provided plenty of turning power at low and high speeds. On-power turning was predictable and neutral, and the truck transitioned very well from side-to-side at low to medium speeds. There’s a fair amount of off-power oversteer that may or may not be welcome depending on your driving style. If the oversteer is uncomfortable, pushing the battery placement more toward the rear, via the foam spacers, will help mellow out the steering. During sweeping turns, the truck showed a fair amount of body roll. Serpent offers an optional swaybar set that can help, as can spring rate and damping changes—if you’re worried about track performance, that is. If you’re buying the Spyder RTR just for high-performance playing around, you won’t notice or care. The trucked jumped well on the track, as the stock shocks are excellent for the class. They are smooth, responsive and soaked up imperfections and small bumps. Big jumps can bottom-out the shocks, particularly in the rear, but the Spyder was unfazed and a firmer setup wouldn’t be hard to dial in. The tires are a medium compound and are well-suited for hard-packed dirt and all-around use. The durability of the truck was impressive. After a couple of miscues, and a cringing confrontation with a metal pole on a tennis court, nothing on the truck broke. The bumper absorbed frontal impacts, and the chassis side guards helped deflect glancing blows. FINAL WORD Serpent’s Spyder SCT SRX-2 RM is a racing truck that happens to be assembled and outfitted with electronics for you. It’s definitely a cut above the average RTR, and only a few components separate it from the kit version. Although the price tag is on the higher side of the RTR 2WD short-course truck spectrum, the value is definitely there. Quality is excellent, and it’s hard to spot where Serpent cut corners (other than the missing slipper clutch and programming card). If you are looking for a truck that is equally at home at play and on track, the Serpent Spyder SCT SRX-2 RM deserves a serious look. SOURCES Serpent serpent.com MaxAmps maxamps.com + Roomy chassis Impressive electronics Ready-to-race RTR Lightweight and durable - No slipper clutch Speed control programming card not included

VEHICLE SPECS Item no.: 500005 Scale: 1/10 Price: $390 Weight, as tested: 4 lb. 6.4 oz. (1996g) CHASSIS Material: 3mm Composite plastic Type: Semi-tub SUSPENSION Type: Independent H-arm with upper link Inboard camber link positions (F/R): 3/2 Outboard camber-link positions (F/R): 2/3 Shock positions; shock towers (F/R): 4/4 Shock positions, arms (F/R): 2/2 SHOCKS Bodies: Aluminum, threaded Bore: 12mm Shafts: 4mm plated steel Volume compensation: Emulsion-type (stock) DRIVETRAIN Type: 2WD Spur gear/pinion: 76/21, 48 pitch Slipper clutch: None Differential: Sealed bevel, steel gear Driveshafts: Steel CV-type Bearings: Rubber-sealed WHEELS & TIRES Wheels: Serpent white spoke, 12mm Hex Tires: Dragon-RC SCT Inserts: Foam INCLUDED ELECTRONICS Transmitter/receiver: Dragon-RC DTS-2 2.4GHz / Dragon-RC, 3-channel Servo: Dragon-RC 210004, 0.13S, 6.5 kg Speed control: Dragon-RC DX-10 WP 45A-Fan Motor: Dragon-RC 9T (3550kV), 540-size brushless TEST GEAR (NOT INCLUDED) Batteries: MaxAmps 2S/3S, 5450mAh, 120C LiPos

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TEST GEAR MaxAmps 2S and 3S LiPo Battery Packs MaxAmps 2S and 3S, 5450mAh LiPo packs fit perfectly into the SRX-2. MaxAmps allows users to customize their packs when ordering them online by specifying the type of connector, balancing plug and cell case. The packs are waterproof, are capable of charging at a 5C rate and are backed by a lifetime warranty. MaxAmps has a huge variety of battery packs available. They have a battery to work in just about every vehicle on the market.