Attack the Competition!
This article was originally published in RC Driver’s June 2015 issue.
Serpent has really been on the move, really on the move to be exact. They have been pumping out race ready machines in all popular racing classes and then backing up their competition vehicles with ready-to-run machines so that casual racers and bashers, too, can enjoy competition quality and design in a package that’s easy to take from the box to the play site. But what we’re going to check out on these pages is a new release in the short course world that caught many racer’s eyes when it was announced about a year ago, the Spyder SRX2 SC RM. The SC RM is a pure racing SC machine designed by world champion driver, Billy Easton, who has also developed many other successful Serpent platforms. This is a buildup kit as you would expect from a racer and features a number of cool and innovative designs that we are looking forward to discussing in detail and then see how they work on the track.
AT A GLANCE
WHO MAKES IT: Serpent
WHO IT’S FOR: Intermediate to advanced driver
PART NUMBER: 500004
HOW MUCH: $269.99
BUILD TYPE: Kit
• Uses spring steel for tie-rods and driveshafts
• Highly tunable suspension
• Large 12mm aluminum threaded shocks
• Slipper clutch adjustable from outside the gear cover
• Stable and nimble handling characteristics
• Make sure you have a 4.5mm nut driver for the ball studs
• Not able to convert to mid motor
The Serpent Spyder SRX2SCRMisforonea long name to spit out every time you tell a driver what you are run- ning, but it’s a worthy name to boast about. The truck has the quality and design that racers are looking for to put them up in front in the main. The tuning and handling is on-point, I just wish there was a mid-motor option, but I did like the rear motor setup in our tests.
TOOLS AND ACCESSORIES INCLUDED
• Differential greases
• 7.4V LiPo Pack
• LiPo charger
• Radio System
• High Torque Servo
• Electronic Speed Control & Motor
• ProTek 2S 100C LiPo Battery- Protea offers a variety of packs suited for racing with hard cases and 100C rating. The packs also feature 5mm bullet tubes for high current application, perfect for this truck’s mod setup.
• Hobbywing Xerun 120A V3.1 Blue ESC- This ESC features a blue aluminum heat- sink case with fan and an integrated switch. It is fully programmable with use of the optional programming card or you can use one of the 10 preset profiles to tune the ESC to the operation you need.
• Spektrum S6180 Servo – The truck was outfitted with a Spektrum radio so it was only proper to drop in this S6180 servo which is perfect for 1/10 use with its 100in- oz output and .14 second reaction time.
ADDITIONAL ITEMS USED
• Spektrum DX4R radio system
• AKA Soft Handlebar Tires
HOP-UPS WE RECOMMEND
• Aluminum Steering Rack, 500236
• Rear Bulkhead Weight, 500244
• Vented Aluminum Slipper Plates, 500242
In an RC world moving to aluminum chassis it’s interesting that Serpent went with a composite chassis for this truck. The narrow, tub-like chassis has a long battery tunnel to adjust weight bias by moving the battery pack. Large structures bolt to the chassis and are are actually more functional than the nerf bars we would normally see. You can install Lexan plates here to help direct airflow from packing up under the body. A large front bumper protects the SRX2 SC and will help skid the truck over bumps or out of nose- dives. The rear bumper offers protection, too, and has mud flaps if you must have that classic SC look.
The suspension features composite suspension arms with a gull-wing shaped front arm. At the ends of the front arms, the caster blocks feature inserts that allow you to tune caster and the steering spindle houses 5×10 bearings for the spring steel axle to spin in. Spring steel is also used for the tie-rods because it’s strong and lightweight. All of the spring steel hinge pins on the truck are captured and if that wasn’t enough spring steel for you, all of the ball studs are machined from the same material. Then moving out back, the rear arms mount into captured pivot blocks. The FR bock is aluminum and the RR composite and features inserts to adjust anti-squat and toe. On the outside of the rear arms, bulky hubs support the axles with oversized bearings. The composite shock towers feature a number of holes to alter the position of the 12mm bore aluminum oil-filled coil-over shocks. The shocks are dual O-ring sealed with bleeder caps for an emulsion style shock setup.
The steering cranks sit under the arced front bulkhead and swing a composite drag link bar. Ball bearings support the cranks and bar for smooth operation and the compact assembly lets the servo sit closer to the front of the truck. Then at the end of the tie-rods, the spindle arms bolt on and can be swapped out with optional arms to adjust Ackermann.
The composite transmission case is bearing filled and supports the three-gear tranny setup, upper main shaft gear, idler and diff gear. The differential is a ball diff with steel outdrives. A dual pad slipper sits in front of the motor plate and can be adjusted from the motor side of the transmission which makes fine tuning much easier when you are trackside. Thin universal driveshafts send power to the wheels which is fine in our book because the shafts are made of spring steel. Wide offset 12mm clamping aluminum hex hubs are used to mate up with the wheels.
The kit goes together well and the instructions are easy to follow. During the build I did have to hunt down a 4.5mm nut driver to make ball end installation easier, but luckily I had one in my Hudy tool arsenal. Other neat features on the truck include adjustable body posts, rear lower bumper skid to protect the motor, a four point thumb screw battery retainer and white spoke rims with predrilled air vents. The included clear body has an awesome low slung SC shape that can be vented and includes side dams in the kit to direct air flow off the back deck.
JUMPING AND HANDLING
Our indoor test track didn’t have a lot of big jumps but there are a few that will send a truck sailing through the air. As I approached one of the larger jumps for the first time, I motored up and sailed it off the face of the jump and the SRX2 SC caught a lot of air… inside the body. The nose sailed up and I landed on the rear bumper which sent the truck tumbling. After a few more laps with wild, aired-out jumps, I headed back to the pits to vent the body and add the side wings to the bed. Now back on the track, the truck sailed over the jumps with a level attitude and felt much more stable. Now I was landing on all four tires and the truck settles down after a jump well. But in the handling department, the rear didn’t feel as planted as I would have liked. I laid down the rear shocks on the tower and this helps give the rear of the truck a planted feel. I also added an ounce of weight to the rear of the truck to get some weight on the rear wheels.
ACCELERATION AND BRAKING
Talk about punch, the Hobbywing 8.5T motor had plenty of power and the acceleration felt boosted in the short shoots. On the straight, the truck pulls hard and is certainly fast, but under hard braking you can spin out. You really need to pick your brake point and stick to it and try not to late brake or you might get the truck crossed up.
On power the front end feels a little light so you get some push on the high speed corners on entry and it tightens up mid turn as you roll off the throttle. On some of the low speed corners, the nose of the truck drops and digs in the wheels for some tight turns. There was a little bit of oversteer, but as I started to play with tires and sauce, I was able to get the truck to corner well. I used AKA soft Wishbone 2 tires up front and super soft in the rear with Team Maximus “The Stuff” tire traction in the rear which gave me the right amount of traction outback with just a little push up front without the oversteer.
With race trucks like the SRX2 SC, we test them like race trucks. Drive them hard on the track and if something gives, we talk about it. We’re not about to take this type of truck outside and aim it at fences. So with that said, as you can imagine, this truck hit a lot of black corrugated pipes, some jump faces, and I even broadsided the wall at the end of the straight, but nothing broke. The diff did feel a little worn after two race days on it, but it didn’t noticeably affect performance.
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SPECS AND TUNING OPTIONS
LENGTH: 21.26 in. (540mm)
WIDTH: 11.61 in. (295mm)
WHEELBASE: 12.99 in (330mm)
WEIGHT: 4.14 lbs. (1877.9g)
BODY, WHEELS AND TIRES
BODY: Racing short course
WHEELS: White Multi-spoke
WHEEL ADAPTER TYPE: 12mm
TIRES: Not Included
SHOCK POSITIONS: Multiple arm and tower
CAMBER: Adjustable Rod
ROLL: Multiple pivot locations
WHEELBASE: Adjustable in rear hub
RIDE HEIGHT: Adjustable via preload collars
MISC: Adjustable rear toe and antisquat
TYPE: Dual Crank
TOE: Adjustable Rods
TYPE: Tub style
TYPE: Rear Motor 2WD
DIFFERENTIAL: Ball Diff
CLUTCH TYPE: Triple pad slipper
GEAR RATIO: 2.43:1
BEARINGS: Rubber shielded
Serpent certainly has another impressive competition machine in their lineup with the SRX2 SC RM. This SC truck has plenty of features in the tuning department that will let you dial it in to almost any track condition. The one hold-back it has is that it’s not capable of being converted to mid motor, but it does handle well in its rear motor setup. The parts quality is great and it’s fast on the track, just make sure to vent the body or you’ll have some wild flying jumps on your hands.
AKA Products Inc. raceaka.com, 951-677-2500
Hobbywing falconsekido.com, 800-720-2351
ProTek distributed by A Main Hobbies, amainhobbies.com, 800-705-2215
Serpent Inc. USA serpent.com, 305-639-9665
Spektrum distributed by Horizon Hobby, spektrumrc.com, 217-352-1913