Stuff You Should Know
about the tRX- 4
Trail Modes and Metal-Gear Muscle
At first glance, the TRX- 4’s power system
looks like the good ol’ XL- 5 speed control and
Titan 550 motor. But look closer and you’ll
see these are actually new components. The
motor is a new 21-turn model for maximum
torque, and it has reverse rotation as required
by the TRX- 4’s drivetrain. The speed control is
the XL- 5 HV, which is rated for 3-cell (3S) LiPo
batteries. The speed control also gets two new
modes: Trail and Crawl.
Trail mode: Default setting. Offers about
20 percent drag brake when the trigger is
in neutral. Reverse is “double pump”: first
application of up-trigger is brake, second
application activates reverse.
Crawl mode: Neutral trigger activates “Hill
Hold” brake to prevent rolling off inclines and
obstacles. Applying up-trigger activates
reverse’; no “double pump” required.
Like the standard XL- 5 speed control, the
3S version also has Sport, Race, and Training
modes. Sport mode will let you run without
drag brake, Race mode eliminates reverse for
track use (we doubt that mode will get much
use), and Training mode cuts speed and power
by 50 percent—useful in Traxxas’ high-speed
models, but you probably won’t be tapping it
with the TRX- 4.
look closer: That’s actually a new “3S” version of
the Xl- 5 speed control with Trail and Crawl modes,
and the motor is a 21-turn, reverse-rotation Titan.
No skimping on the servo.
The 2075X is Traxxas’ first
servo, and it’s rated for
125 oz.-in. of torque.
Linked Suspension and Scale Shocks
Traxxas set aside its Ultra and GTR shock designs in favor of
all-new dampers with scale-appropriate dimensions. The
GTS shocks are bladderless and use dual X-rings to seal the
7mm-bore aluminum bodies against 3mm shafts. Threaded
collars set preload, and damping is fairly heavy with the
factory pistons and oil—all the better to take the edge off
bumps when cruising in high gear. A 3-link/panhard-bar
setup locates the front axle, and a 4-link setup takes care of
the rear, with 5mm steel links, heavy-duty rod ends, and steel
hollow balls used throughout.
Note how the shock is fully
supported by the tower.
The Tr X- 4 scored a 1019 on our articulation ramp—the highest score
we’ve measured for a trail truck.
The G TS shocks
have 7mm bores,
and are sealed by a
pair of X-rings.