Traxxas 39087-1 User Manual

Page 23

E-MAXX BRUSHLESS • 23

TUNING ADJUSTMENTS

MOTOR AND GEARING

The E-Maxx is equipped from the factory with a 68-tooth spur gear
and 17-tooth pinion gears. E-Maxx has a large range of gearing
making it suitable for many different types of applications and
environments. If you want more acceleration and less top speed,
use a smaller pinion gear (fewer teeth, higher numerical ratio). The
overall reduction is the number of turns the motor makes for one
revolution of the tire. Higher numerical ratios provide more torque,
lower numerical ratios provide more top speed. Use the following
formula to calculate the overall ratio for combinations not listed on
the gear chart:

Caution!

Operating your model with 65+mph gearing

• The 28/65 ratio for use with 6S LiPo batteries is designed

for maximum speed on smooth surfaces only, with steady
acceleration to full throttle and optional Talon tires installed.

• Do not use this gear ratio for general driving.
• Avoid repetitive starting and stopping.
• Do not use the 28/65 ratio with NiMH batteries or low-capacity

LiPo batteries. 5000mAh LiPo batteries are recommended.

• Allow the motor to cool between runs, and monitor motor

temperature.

• Do not use the 28/65 gear ratio for off-

road running or overheating and damage
may result.

• Do not allow the motor temperature

to exceed 200° F or damage and motor
failure may result. To accurately monitor
motor temperature and prevent
overheating, a telemetry temperature
sensor (part #6523) is included with
your model. The sensor is installed
on the motor to continually monitor
temperature as you drive. See page 26 for
more information on real-time telemetry
and TQi advanced tuning.

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.
Loosen the motor screws and
slide a motor and pinion gear
into the spur gear. Retighten the
motor screws and then remove
the strip of paper. Repeat with
the other motor. You should
be able to run a fresh strip of
paper through the gears without
binding them.

# Spur Gear Teeth

x 5.22 = Final Gear Ratio

# Pinion Gear Teeth

Motor

Screw

Strip of

Paper

Gearing Compatibility Chart:
The chart below shows a full range
of gear combinations. This does NOT
imply that these gear combinations
should be used. Over-gearing
(bigger pinions, smaller spurs) can
overheat and damage the motor
and/or speed control.

DNF

4.53

DNF

4.25

DNF

4.00

DNF

3.78

3.42

3.58

3.25

3.40

3.10

3.24

3.09

DNF

Pinion Gear

Spur Gear

Stock gearing

Optional included gearing (4S LiPo)

Recommended gearing
for all battery types

Recommended gearing
for 4S LiPo only

Not recommended

Does not fit

Speed

35+ mph

40+ mph*

50+ mph

65 mph

& Beyond

Pinion/Spur

17/68

20/68

17/68

28/65**

Battery

Twin 7-Cell NiMH

(14 cell total)

Twin 2S LiPo

(4S total)

Twin 3S LiPo

(6S total)

Twin 3S LiPo

(6S total)

Nominal Voltage

16.8V

14.8V

22.2V

mAh

4000+ mAh

5000+ mAh

Skill Level

Your Battery Selection and Pinion Gear
Selection Determines Your Speed.

How Fast Do You Want To Go?

For Expert Drivers

*with included optional gearing
**28T pinion and 65T spur not included.

For high-speed running on smooth surfaces with optional Talon tires only.

Model #39085