Tech Center
CAN I USE DIFFERENT
BRANDS?
QI run a stadium truck that I have been bashing for about a year and I am looking to upgrade the motor and speed control
to go racing. It seems like the best deal is to get a brushless motor
and speed control combo package from the same manufacturer.
If I buy a 17. 5 brushless combo for running a stock class and I
later decide to run a modified class with a lower turn motor, can I
use a motor from a di;erent manufacturer with the same speed
control?
AWhile 2.4GHz radio systems need to all be the same brand to guarantee proper functionality, brushless motors and speed
controls are interchangeable between brands. ;e main consid-
erations when using mismatched brands of motor and speed
control is that the architecture of the system stays the same and
the other consideration is to make sure that the speed control
is rated for the amp draw of the new motor. An extreme case of
mismatching would be trying to run an 1/8-scale brushless motor
with a 1/10-scale sized speed control. In this case, the
speed control would overheat and burnout. However,
it may also be possible to cook your speed
control with a low turn motor with the
same can size. Consult the manual
and the motor’s specs before mak-
ing a purchase.
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IT’S FASTER … BUT
SLOWER
Q I recently bought an RTR touring car for some parking lot fun and after I got the hang of driving it smoothly, I
decided that I needed some more speed. I have read that using a bigger pinion
and a smaller spur gear will yield more top speed, so I went from a stock gearing setup of a 15-tooth pinion and 61-tooth spur, to a 25-tooth pinion and a
55-tooth spur. After the gear change, my car feels like it runs slower and it has
lost its pep. Why isn’t my car running faster?
AYou are correct in your assumption that a bigger pinion and a smaller spur will yield higher top speed. ;e caveat to this is that the gearing will yield
higher speed only if the motor and electronics have enough power to run the
increased gearing change. In full-scale car terms, if you gear a 100 horsepower compact car to run 300mph, it will never get to that speed because
the engine is not powerful enough to pull that gear. I suspect this is the
case with your touring car. ;e car started out with a 4.06 gear ratio (spur
divided by pinion) and you changed it to 2.20 in one step, which is a massive
jump. ;e motor needs to put out much more power and the RTR electronics may not be able to handle it. If you tried to touch the motor or speed control
after the gear change, you probably also noticed that it was really hot from the
extra amp draw. Try installing the original gear set and run the car again to make
sure that it feels that same to confirm you have not damaged the electronics.
Leave the original spur in the car and then go up one or two teeth on the pinion
gear until you get a good balance between top speed and acceleration. e o
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