Losi Gear Ratio Question?

C Hing,

What size of Pinion should be used for Team Losi XXX 2WD?

Spur = 78
Internal drive ration = 2.43

I am using HobbyWing ECS 60A + 5.5T brushless motor.

Many Thanks!

Using 5.5T brushless for 2WD offroad is not recommended since it will fly.  Modified drivers usually use 6.5 to 7.5.

However, if you want to try 5.5T, the final drive ratio (FDR) should be around 11.

So the calculation is as follows:
Pinion = Spur / (FDR / IDR)
P = 78 / (11 / 2.43) = 17

In your case, use 17 first to see if you can handle the speed. (or be able to control the car)