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XO-1
ADVANCED TUNING ADJUSTMENTS
GEARING
Changing the gearing allows you to fine tune the speed of the
model and control the temperatures of the battery packs 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:
When using higher gear ratios, it is important to monitor the
temperatures of the battery and motor. If the battery 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
weight and operates freely with no excessive friction, dragging, or
binding, and the battery is fully charged and in good condition.
Note
:
Check and adjust gear mesh if a spur and/or pinion gear is changed.
This model is equipped with a Traxxas/Castle Creations Big Block
motor. The gear combination that comes stock on each model
provides good overall acceleration and top speed. If you want more
top speed, install the included optional large pinion gear (more
teeth).
The included optional large pinion gear is intended for
high-speed running ONLY! This gearing is not recommended for
repetitive starting and stopping.
Repetitive starting and stopping with the high-speed gear will
result in motor overheating. The speed control’s thermal overload
protection system will shut down power in the event of severe
overheating. The model will operate normally once the speed
control reaches safe operating temperature. To prevent motor
overheating, only use recommended gearing and only drive in the
manner prescribed for those gear ratios.
TUNING THE SEALED GEAR DIFFERENTIALS
The action of the your model’s front and rear gear differentials
can be tuned for different driving conditions and performance
requirements, without major disassembly or removal of the
suspension system.
From the factory, the differentials are sealed to maintain consistent
long-term performance. Changing the oil in the differential with
either lower or higher viscosity oil will vary the performance
characteristics of the differentials. Changing to a higher viscosity oil
in the differential will reduce the tendency for motor power to be
transferred to the wheel with the least traction. You may notice this
when making sharp turns on slick surfaces. The unloaded wheels
on the inside of the turn have the least traction and tend to spin
up to extremely high rpms. Higher viscosity (thicker) oil causes the
differential to act like a limited-slip differential, distributing more
equal power to the left and right wheels.
Your model will generally benefit from higher viscosity oil
when being driven on low traction surfaces.
Note
: Heavier oil will
allow power to be transferred even with one or more tires off the
ground. This can make the vehicle more likely to overturn on high-
traction surfaces.
From the factory, the front differential is filled with SAE 100,000W
viscosity silicone oil. The rear differential is filled with SAE 10,000W.
Only use silicone oil in the differentials. Traxxas offers SAE 10,000W,
30,000W, and 50,000W viscosity oil (see your parts list). The
differentials have to be removed from the vehicle and disassembled
to change/replace oil.
Follow the steps below to access and refill the front and rear differentials:
Front differential:
1. Remove the three 4x15mm countersunk screws that fasten the
body mount to the splitter.
2. Remove the two 4x30mm countersunk screws from the
underside of the chassis.
3. Remove the 3x15mm button head screws that fasten the body
mount to the differential case. Set the body mount aside.
4. Remove the 3x15mm button head screw from the front tie bar
and remove the tie bar from the vehicle.
Gearing Compatibility Chart:
The chart below shows
recommended gear combination
ranges for your model.
Spur Gear
Pinion Gear
46
50
54
11
-
12.94
13.97
12
-
11.86
12.81
13
10.07
10.95
11.82
14
9.35
10.16
10.98
15
8.73
9.49
10.25
16
8.18
8.89
9.61
17
7.70
8.37
9.04
18
7.27
7.91
8.54
19
6.89
7.49
8.09
20
6.55
7.12
7.68
21
6.23
6.78
7.32
22
5.95
6.47
6.99
23
5.69
6.19
6.68
24
5.46
5.93
6.40
25
5.24
5.69
6.15
26
5.04
5.47
5.91
27
4.85
5.27
5.69
28
4.68
5.08
5.49
29
4.51
4.91
5.30
30
4.36
4.74
-
31
4.22
4.59
-
32
4.09
4.45
-
33
3.97
4.31
-
34
3.85
-
-
Stock Out of Box Setup, 50mph
with 3S LiPo batteries.
Fits, but extended running is
not recommended. See warnings!
Included optional gearing, for
high-speed running only, 100mph.
Not recommended for use with
2S LiPo or NiMH batteries.
Does not fit.
Fits, will reduce top speed
but increase run time.
# Spur Gear Teeth
x 2.85 = Final Gear Ratio
# Pinion Gear Teeth
Warning!
Do not drive the model at lower speeds in a confined
space, with repetitive starting and stopping, with the gear
ratios in the yellow and red zones shown in the chart at left. This
will cause the motor to overheat, resulting in permanent damage to
the motor.
Overheating is not covered by the limited warranty.
A thermal overload sensor is installed to help protect against
catastrophic overheating. The speed control will flash its red and
yellow LEDs to indicate the motor is being overheated, but this
should not be relied upon as an absolute failsafe.