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Gearing Compatibility Chart:
The chart below shows recommended
gear combination ranges for your model.
Spur Gear
46
50
54
11
-
-
4.91
12
-
-
4.50
13
-
-
4.15
14
-
3.57
3.86
15
-
3.33
3.60
16
-
3.13
3.38
17
-
2.94
3.18
18
2.56
2.78
3.00
19
2.42
2.63
-
20
2.30
2.50
-
21
2.19
2.38
-
22
2.09
2.27
-
23
2.00
-
-
24
1.92
-
-
25
1.87
-
-
26
1.77
-
-
Out of Box Setup; recommended for most
running, 4S/6S/8S LiPo.
2S 7600mAh + recommended
3S 8400mAh + recommended
4S 6700mAh + recommended
Provided optional gearing.
Use with 4S/6S/8S LiPo for high speed
runs on hard smooth surfaces only.
2S 7600mAh + recommended
3S 8400mAh + recommended
4S 6700mAh + recommended
Usable gearing range for 4S/6S/8S LiPo.
Increases torque and run time.
2S 5000mAh + recommended
3S 5000mAh + recommended
4S 6700mAh + recommended
Use with 4S/6S/8S LiPo for high speed runs
on hard smooth surfaces only.
2S 7600mAh + recommended
3S 8400mAh + recommended
4S 6700mAh + recommended
Fits; not for use with 4S/6S/8S LiPo.
Not suitable for use with stock power
system (VXL-8s ESC and 1200XL motor).
Does not fit.
28 • XRT
ADVANCED TUNING ADJUSTMENTS
Roll Center
XRT has provisions for adjusting the roll center geometry of the front
and rear suspension. Roll center refers to the virtual axis around
which the chassis will roll when subjected to cornering forces. The roll
center of the vehicle can be raised by mounting the inner ends of the
camber links in a lower position. Raising the roll center will effectively
increase the roll stiffness of the vehicle (similar to installing swaybars).
Adding roll resistance to one end of the vehicle will tend to add
traction to the opposite end. For example, increasing roll resistance
in the rear will provide more traction for the front wheels and
potentially more steering.
Raising the roll center on the front and rear equally will increase
overall roll resistance without changing the handling balance. The
default factory locations are designed to make the truck easier and
more forgiving to drive and less likely to traction roll in turns. XRT
features two roll center positions that can be adjusted for tuning.
The upper position lowers the roll center; the bottom position
raises the roll center. Out of the box, XRT is setup with the optimum
roll center for handling and performance. The stock setting for the
rear links is in the bottom position and the front links use the upper
position.
Front Roll Center Positions
Rear Roll Center Positions
Note: If you place the front
links in the bottom position
(not stock), then the pivot balls
in the steering will need to be
flipped. The outer pivot balls
come out of the box in the
lower position (A). When the roll
center is moved, the offset will
need to be flipped (B).
Gearing
One of the more significant advantages to your model's transmission
is the wide range of available gear ratios. Changing the gearing
allows you to fine tune the speed of the model and control the
temperatures of the battery pack and motor. Use a lower gear ratio
(numerically larger) to reduce current draw and temperatures. Use
a higher gear (numerically lower) to increase top speed. Use the
following formula to calculate the overall ratio for combinations not
listed on the gear chart:
# Spur Gear Teeth
# Pinion Gear Teeth
When using higher gear ratios, it is important to monitor the
A - Lower Roll Center
temperatures of the battery, motor, and speed control. If the battery
(Stock)
is extremely hot (150°F) and/or the motor is too hot to touch (200°F),
your model is probably over-geared and drawing too much current.
This temperature test assumes that the model is close to factory stock
B - Raise Roll
weight and operates freely with no excessive friction, dragging, or
Center
binding, and the battery is fully charged and in good condition.
Note: If not using the pin system, check and adjust gear mesh if a
spur and/or pinion gear is changed.
This model is equipped with a Velineon 1200XL brushless motor. The
gear combination that comes stock on each model provides good
A - Lower Roll
overall acceleration and top speed. If high-speed gearing is used, it is
Center
not recommended for off-road or repetitive starting and stopping.
Temperatures and Cooling
B - Raise Roll
B - Raise Roll
The XRT includes several features to help cool the electronic
Center (Stock)
Center (Stock)
components: a motor temperature sensor, motor cooling fans, motor
heat sink, and electronic speed control cooling fan.
A
B
Stock
x 8.11 = Final Gear Ratio
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