EN
8
LOSI
®
TENACITY
™
LASERNUT ULTRA 4 1/10 4WD RTR ROCK RACER • INSTRUCTION MANUAL
PRECAUTIONS
• Never touch moving parts.
• Never disassemble while the batteries are installed.
• Always let parts cool before touching.
GEARING
Your vehicle has been equipped with the optimal gearing installed for the use of a 4S battery.
It offers an ideal balance between speed, power and efficiency. Should you decide to
customize your vehicle with a 3S battery it is necessary to change to the 14T pinion (included).
Installing a pinion gear with fewer teeth or a spur gear with more teeth will provide greater
torque but will reduce top speed. Likewise, a pinion gear with more teeth or a spur gear with
fewer teeth will reduce torque and increase top speed. Care should be taken when installing
larger pinion gears as this can "overgear" the vehicle, resulting in overheating of the motor
and ESC. When testing different gearing options, pay close attention to the temperature
of the motor and speed control to ensure you are operating within the temperature range
of the components. The motor or ESC should never be so hot that it cannot be touched. If
temperatures are too hot, a different gearing combination with a lower pinion gear and/or
higher spur gear is suggested.
CHANGING THE PINION GEAR/GEAR RATIO
1. Remove the screw holding the pinion gear cover in place.
2. Loosen the set screw and remove the installed pinion gear.
3. Loosen the motor screws and slide the motor back.
4. Place the new pinion on the end of the motor shaft so the set screw is located
over the flat on the shaft.
5. Position it so the teeth line up with the spur gear and secure the pinion by tightening
the set screw.
6. Set the gear mesh.
SPEKTRUM
™
FIRMA
™
1900KV BRUSHLESS MOTOR
SETTING THE GEAR MESH
The gear mesh has already been set at the factory. Setting it is only necessary when changing
motors or gears.
Proper gear mesh (how gear teeth meet) is important to the performance of the vehicle. When
the gear mesh is too loose, the spur gear could be damaged by the pinion gear of the motor. If
the mesh is too tight, speed could be limited and the motor and ESC will overheat.
1. Loosen the motor screws and slide the motor back.
2. Put a small piece of paper between the pinion and spur gears.
3. Push the gears together while tightening the motor screws.
4. Remove the paper. Check the mesh at 3–5 different locations around
the spur gear for a small amount of movement.
5. Install the gear cover.
NOTICE:
If you are using a 3S Li-Po battery, use the included 14T Pinion gear. If you are
using a 4S Li-Po battery, use the installed 12T pinion gear. Using a 14T pinion gear with a
4S Li-Po battery will result in damage to the ESC and motor.
TELEMETRY SETTINGS
If using the Spektrum Dashboard app or the optional speedometer module on your
transmitter, set the motor pole count to 4 and the rollout distance to 1.5" (38.1mm).
TROUBLESHOOTING GUIDE
PROBLEM
POSSIBLE CAUSE
SOLUTION
Vehicle does not operate
Battery not charged or plugged in
Charge battery/plug in
ESC switch not “On”
Turn on ESC switch
Transmitter not “On” or low battery
Turn on/replace batteries
Motor runs but wheels
do not rotate
Pinion not meshing with spur gear
Adjust pinion/spur mesh
Pinion spinning on motor shaft
Tighten pinion gear setscrew on motor shaft flat spot
Transmission gears stripped
Replace transmission gears
Drive pin broken
Check and replace drive pin
Steering does not work
Servo plug not in receiver properly
Make sure the steering servo plug is connected to the receiver steering channel, noting proper polarity
Servo gears or motor damaged
Replace or repair servo
Will not turn one direction
Servo gears damaged
Replace or repair servo
Motor does not run
Motor wire solder joint is damaged
Resolder the motor wire with the proper equipment
Motor wire broken
Repair or replace as needed
ESC damaged
Contact Horizon Hobby Product Support
ESC gets hot
Motor over-geared
Use smaller pinion or larger spur gear
Driveline bound up
Check wheels and transmission for binding
Poor run time and/or sluggish
acceleration
Battery pack not fully charged
Recharge battery
Charger not allowing full charge
Try another charger
Driveline bound up
Check wheels, transmission for binding
Poor range and/or glitching
Transmitter batteries low
Check and replace
Vehicle battery low
Recharge battery
Loose plugs or wires
Check all wire connections and plugs
LIMITED WARRANTY
What this Warranty Covers
Horizon Hobby, LLC, (Horizon) warrants to the original purchaser that the product purchased (the
“Product”) will be free from defects in materials and workmanship for a period of 2 years from
the date of purchase.
What is Not Covered
This warranty is not transferable and does not cover (i) cosmetic damage, (ii) damage due
to acts of God, accident, misuse, abuse, negligence, commercial use, or due to improper use,
installation, operation or maintenance, (iii) modification of or to any part of the Product, (iv)
attempted service by anyone other than a Horizon Hobby authorized service center, (v) Product
not purchased from an authorized Horizon dealer, or (vi) Product not compliant with applicable
technical regulations or (vii) use that violates any applicable laws, rules, or regulations.
OTHER THAN THE EXPRESS WARRANTY ABOVE, HORIZON MAKES NO OTHER WARRANTY
OR REPRESENTATION, AND HEREBY DISCLAIMS ANY AND ALL IMPLIED WARRANTIES,
INCLUDING, WITHOUT LIMITATION, THE IMPLIED WARRANTIES OF NON-INFRINGEMENT,
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. THE PURCHASER
ACKNOWLEDGES THAT THEY ALONE HAVE DETERMINED THAT THE PRODUCT WILL SUITABLY
MEET THE REQUIREMENTS OF THE PURCHASER’S INTENDED USE.
Purchaser’s Remedy
Horizon’s sole obligation and purchaser’s sole and exclusive remedy shall be that Horizon
will, at its option, either (i) service, or (ii) replace, any Product determined by Horizon to be
defective. Horizon reserves the right to inspect any and all Product(s) involved in a warranty
claim. Service or replacement decisions are at the sole discretion of Horizon. Proof of purchase
is required for all warranty claims. SERVICE OR REPLACEMENT AS PROVIDED UNDER THIS
WARRANTY IS THE PURCHASER’S SOLE AND EXCLUSIVE REMEDY.
Limitation of Liability
HORIZON SHALL NOT BE LIABLE FOR SPECIAL, INDIRECT, INCIDENTAL OR CONSEQUENTIAL
DAMAGES, LOSS OF PROFITS OR PRODUCTION OR COMMERCIAL LOSS IN ANY WAY,
REGARDLESS OF WHETHER SUCH CLAIM IS BASED IN CONTRACT, WARRANTY, TORT,
NEGLIGENCE, STRICT LIABILITY OR ANY OTHER THEORY OF LIABILITY, EVEN IF HORIZON HAS
BEEN ADVISED OF THE POSSIBILITY OF SUCH DAMAGES. Further, in no event shall the liability
of Horizon exceed the individual price of the Product on which liability is asserted. As Horizon
has no control over use, setup, final assembly, modification or misuse, no liability shall be
assumed nor accepted for any resulting damage or injury. By the act of use, setup or assembly,
the user accepts all resulting liability. If you as the purchaser or user are not prepared to
accept the liability associated with the use of the Product, purchaser is advised to return the
Product immediately in new and unused condition to the place of purchase.
