Headset adjustment after maintenance, drop bar center alignment is not a trivial matter.
There's also a way to do it by attaching a string in the middle of the stem, but there's a video that shows a simple solution with just one stick, so I'm sharing it.
There may be a slight error in Limb Brake... but it seems to be a possible method for disc brakes.
Another way is to make loops on both ends of the string, mark the overall midpoint, and then hook it onto the hood or drop bar and align the tire with the center.
