choosing a pinion gear
12-17-2014, 09:27 AM
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choosing a pinion gear
i have a 87/18 spur/pinion gearing and wanted to get a bit more top end. can i notice a difference with a 20t or 21t pinion? i see bigger ones, but i don't want to totally give up acceleration and i don't even think the motor mount slots can move that far anyway.
12-17-2014, 12:45 PM
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got an e-firestorm with the stock brushless motor.
i know it'll go faster but i'm wondering if only a 2 or 3 tooth difference is noticable or if i'm better served by changing to an even larger pinion and pair it with a smaller spur gear.
i know it'll go faster but i'm wondering if only a 2 or 3 tooth difference is noticable or if i'm better served by changing to an even larger pinion and pair it with a smaller spur gear.
12-17-2014, 03:10 PM
#4
You could keep trying pinions until your motor gets too hot to hold your fingers on the motor. I believe the "critical" temp. is around 160ºF for a brushless motor. I myself need to get a infrared thermometer in the spring. The manual should give you good suggestions at pinion gear range to start with. It all depends on what motor you have and the kv rating and the rpms. I'm guessing the manual says a range around 16T ~ 23T pinion gear.
Last edited by RustyUs; 12-17-2014 at 03:36 PM.
12-18-2014, 10:07 AM
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Don't give your truck the finger! The way to gear properly is via temperature. So if you don’t have a temp gauge, get one! Here’s the one I use: http://www3.towerhobbies.com/cgi-bin...&I=LXEMG5&P=ML
Periodically during and after your desired run time check the temperatures of the motor, ESC and battery. Once you have all the temperatures of the electronics right, there’s no need to check during the run unless a condition has changed (see below ***).
motor (>150°), cool ESC --------, cool LiPo -------- = under geared
cool motor --------, hot ESC (>130°), hot LiPo (>120°) = over geared
hot motor (>150°), hot ESC (>130°), hot LiPo (>120°) = way over geared
[ Under geared means you should use a larger pinion and/or a smaller spur. Over geared, visa versa. ]
very hot motor = 160° or more
very hot ESC = 150° or more — (or "thermal" range for the ESC)
very hot LiPo = 130° or more — (very hot NiMh = 150° or more)
warm = happy components
warm motor = 100° to 150° — (the warm range is lower for brushed motors)
warm ESC = 100° to 130°
warm LiPo = ambient temperature to 105° (lower is recommended) —(warm NiMh = 100° to130°)
cool for motor, ESC and battery = ambient temp to 10° over
***The reasons the above are not always true are numerous, but may include:
running in hot weather
running in tall grass (creating major resistance)
sticky drivetrain
wrong motor for the application
wrong ESC for the application
wrong battery for the application
(all of the above will put unnecessary strain on electronics regardless of gearing)
poor quality batteries will heat up regardless of gearing!!!
Using chemical reaction, a LiPo battery will naturally increase in temperature due to use, i.e. current draw. At 140° a LiPo pack will fail (fire). A LiPo should always be below 130° but even lower is highly recommended. Some racers say 100° is best. An overly warm LiPo may be an indication that it is being overtaxed and/or damaged.
It is mandatory to follow the manufacturer’s electronics temperature recommendations. Lowest warm range temperatures are preferable.
Several experts have told me that as a general rule all ESCs and motors should be able to be run without a fan or heat sink. The exceptions to this rule: very hot weather, incorrect application (too small of a motor being used), poor air circulation, etc. Absent the exceptions, electronics will always be in the correct temperature range when geared correctly without the need for fans. Temperature is best controlled by gearing.
According to the official Gearing Chart for Castle 1/10th Scale Motors: "Always check your motor temperature frequently on the first run after changing the gearing, motor or increasing battery voltage! Never let the motor get above 180°F. Use an infrared temperature gun to monitor motor temps. If the motor starts to get close to 180° reduce the pinion size, increase the spur size, or reduce the pack voltage."
Periodically during and after your desired run time check the temperatures of the motor, ESC and battery. Once you have all the temperatures of the electronics right, there’s no need to check during the run unless a condition has changed (see below ***).
motor (>150°), cool ESC --------, cool LiPo -------- = under geared
cool motor --------, hot ESC (>130°), hot LiPo (>120°) = over geared
hot motor (>150°), hot ESC (>130°), hot LiPo (>120°) = way over geared
[ Under geared means you should use a larger pinion and/or a smaller spur. Over geared, visa versa. ]
very hot motor = 160° or more
very hot ESC = 150° or more — (or "thermal" range for the ESC)
very hot LiPo = 130° or more — (very hot NiMh = 150° or more)
warm = happy components
warm motor = 100° to 150° — (the warm range is lower for brushed motors)
warm ESC = 100° to 130°
warm LiPo = ambient temperature to 105° (lower is recommended) —(warm NiMh = 100° to130°)
cool for motor, ESC and battery = ambient temp to 10° over
***The reasons the above are not always true are numerous, but may include:
running in hot weather
running in tall grass (creating major resistance)
sticky drivetrain
wrong motor for the application
wrong ESC for the application
wrong battery for the application
(all of the above will put unnecessary strain on electronics regardless of gearing)
poor quality batteries will heat up regardless of gearing!!!
Using chemical reaction, a LiPo battery will naturally increase in temperature due to use, i.e. current draw. At 140° a LiPo pack will fail (fire). A LiPo should always be below 130° but even lower is highly recommended. Some racers say 100° is best. An overly warm LiPo may be an indication that it is being overtaxed and/or damaged.
It is mandatory to follow the manufacturer’s electronics temperature recommendations. Lowest warm range temperatures are preferable.
Several experts have told me that as a general rule all ESCs and motors should be able to be run without a fan or heat sink. The exceptions to this rule: very hot weather, incorrect application (too small of a motor being used), poor air circulation, etc. Absent the exceptions, electronics will always be in the correct temperature range when geared correctly without the need for fans. Temperature is best controlled by gearing.
According to the official Gearing Chart for Castle 1/10th Scale Motors: "Always check your motor temperature frequently on the first run after changing the gearing, motor or increasing battery voltage! Never let the motor get above 180°F. Use an infrared temperature gun to monitor motor temps. If the motor starts to get close to 180° reduce the pinion size, increase the spur size, or reduce the pack voltage."
