Drivetrain Acceleration Issue (fixed)

Hi everyone,

My drivebase won’t accelerate straight in the forward direction.

I’ve checked to make sure all shafts are in place and that all the motors work.

All motors are brand new which rules out motor damage (unless the motors came defective)

Weight distribution is not an issue as everything is perfectly centered.

Gear slippage is not an issue. Not slippage can be heard.

Coding is not an issue as the code is just 10 lines and is completely empty. I’ve also made all motors controlled by one joystick so they all get the same input.

My only possible explanation would be lack of traction, but even then, the robot accelerates straight when it goes backwards.


20210404_134122 20210404_134116

ok well first of all, what is that bevel gear setup? are you just trying to experiment with bevel gears or is this an actual competition drive design? there are much better and more compact ways to stack your motors above your wheels.

this might be what’s causing your issue. check the friction in each side by pulling the motor shafts out of the motors so that you can spin them. if one side spins longer than the other, that uneven friction is what’s causing the drift. using bevel gears like that is likely to cause quite a bit of friction as well, so there are a lot more placing you could be going wrong friction-wise.

another thing to check is to make sure all the motors are spinning properly in both directions. I’ve had some weird issues with motors in the past spinning full power one way, and then spinning at low or no power in the other direction. This could explain your drifting in only one direction problem.

So basically, check your friction, check your motors, and I would advise you to avoid using bevel gears, especially on your drive.


Please do not use vex bevel gears. :grinning: