So I bought SC18 RTR online for my one of my nephews. The other nephews liked it so much they wanted one too. So went to my LHS and bought another SC18 RTR and one 18T2 RTR for my two other nephews. Wanted to get three SC18's, but my LHS only had an SC18 and 18T2 in stock. The 18T2 is fine and my youngest nephew loves this car since it's faster than his older brother's SC18's and it's shaft drive so no drag in the drivetrain.

As for the SC18's one has a really smooth and free drivetrain, but the other SC18 just feels all bound up which eventually killed the motor. I bought a new motor and I took the whole car apart to see what might be causing the binding as well as inspected and cleaned all the parts. Put everything back together and is still bound up. I did back off some of the screws to see if it would help free it up and it did a little, but once again the motor brushes seized on the commutator. I read I can take out the belt tensioner to free it up? Any other ideas or suggestions?