1/16 SUMMIT • 21
TUNING ADJUSTMENTS
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 climbing, rock crawling, or racing on low traction surfaces.
From the factory, both the differentials are filled with SAE
30,000W viscosity silicone oil. This fluid gives the 1/16 Summit
versatile multi-terrain handling and allows forgiving cornering
on pavement and other high-grip surfaces. For extreme off-
road terrain, the differentials may be filled with thicker fluid to
increase traction, at the expense of high speed cornering stability.
100,000W fluid is a good starting point for extreme-terrain use;
500,000W fluid will virtually lock the differentials. The differentials
must be removed from the vehicle and disassembled to change/
replace oil. Only use silicone oil in the differentials. Traxxas sells a
variety of oil viscosities (see your parts list).
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.
MOTOR AND GEARING
Extensive testing has been done to determine the best gear ratio
for your model. The stock gearing balances power, speed, and
efficiency to optimize the performance of the model. However,
you may wish to try different gear ratios in order to customize the
performance of your model. The gearing chart on this page shows
appropriate gearing for the model.
By installing a pinion with fewer teeth, or a spur gear with
more teeth, the transmission’s final drive ratio is increased.
This means greater rpm is required to achieve a given speed.
Using a numerically higher gear ratio will increase torque, but
reduce top speed. Installing a pinion with more teeth, or a spur
gear with fewer teeth, will decrease the final drive ratio, which
will generally increase top speed but reduce torque. However,
installing too large a pinion will “overgear” the model, which will
reduce performance and may overheat the motor and speed
control. Use the following formula to calculate the overall ratio for
combinations not listed on the gear chart:
Motor Installation
To access the motor,
remove the gear cover
by removing the single
screw on the top of the
gear cover. The motor
uses an aluminum
mount for quick, easy
motor access and
gearing adjustment.
To remove the motor, first open the right battery door and slide
out the ESC. Next, remove the single large hex screw using the
supplied 2.5mm wrench. Then rotate the motor and mount to the
side of the model, and slide backward off the post.
Pinion Gear Installation Instructions
1. Remove the motor as described
in Motor Installation.
2. Use a 1.5mm wrench to loosen the
pinion’s set screw. Remove the pinion.
3. Place the replacement pinion gear onto
the motor shaft. Align the set screw hole
with the flat side of the shaft.
4. Thread a 1.5mm set screw into the
pinion gear but do not tighten it yet.
5. Slide the pinion gear down the motor shaft so the wrench shaft
fits into the notch in the motor mount, as shown. Tighten the
set screw.
Adjusting Gear Mesh
Incorrect gear mesh is the most common cause of stripped spur
gears. Gear mesh should be checked and adjusted anytime a gear
is replaced. Access the gears by removing the single screw on the
top gear cover.
To set the gear mesh,
cut a narrow strip of
notebook paper and
run it into the gear
mesh of the motor.
The motor is mounted
to an aluminum motor mount. Loosen the single motor mount
screw with the provided 2.5mm wrench to slide the motor mount.
# Spur Gear Teeth
x 5.04 = Final Gear Ratio
# Pinion Gear Teeth
Motor Mount
Screw
Do Not Loosen
Gearing Compatibility Chart
The chart on the left shows a full range of
gear combinations. The stock ratio for is
shown in green. The gear combinations
in red are not suitable when using the
included 6-cell battery, speed control
and motor. These gear combinations
have been included in this chart as
they may be used with certain other
aftermarket equipment combinations.
Spur Gear
Pinion Gear
45
50
55
16
-
-
17.33
17
-
-
16.31
18
-
-
15.40
19
-
-
14.59
20
-
-
13.86
21
-
-
13.20
22
-
11.45
12.60
23
-
10.96
12.05
24
-
10.50
11.55
25
-
10.08
11.09
26
8.72
9.69
10.66
27
8.40
9.33
10.27
28
8.10
9.00
9.90
29
7.82
8.69
9.56
30
7.56
8.40
9.24
31
7.32
8.13
8.94
32
7.09
7.88
8.66
33
6.87
7.64
8.40
34
6.67
7.41
8.15
35
6.48
7.20
7.92
36
6.30
7.00
-
37
6.13
6.81
-
38
5.97
6.63
-
39
5.82
6.46
-
40
5.67
6.30
-
41
5.53
-
-
42
5.40
-
-
43
5.27
-
-
44
5.15
-
-
45
5.04
-
-
46
-
-
-
Stock
Requires aftermarket 540 motor to fit
Usable range
Not recommended with stock ESC, motor and batteries
Dual batteries with parallel connector only
Does not fit
