Extreme curve?

[MetaEngineer]

The number of parts in a typical FRC drivetrain can make for a noticeable variation in the speeds of drive units. When run open loop, the drivetrain on our bot this year has one side a few percent faster than the other which made it curve.

Certainly calibrate all motor controllers and double check connections first. You may be able to tweak your drive train for better consistency and find a balance of motor power settings that goes approximately straight, but the real solution is using some form of feedback. A combination of wheel speed encoders and/or a gyro lets the roborio make adjustments on the fly. However this can take a fair bit of time to get coded and tuned in properly.