The wheels are removed by holding the caster from spinning and removing the nut on caster on the inside of the bike bag. Attaching a new scicon aerocomfort replacement wheel is the same, slide the caster into the open hole, hold it in place with channel locks, install the washer and tighten the nut.
The wheels are swivel stem casters, they are 2″ wheels. The thread pitch on the stem is Metric M10-1.5 or SAE 3/8-16. The old stem caster’s stem is 1.25″ long and the new wheel’s stem is 1.5″, so a little of the stem will stick out above the nut, this is not a problem.
You can buy the replacement wheels on Amazon: https://amzn.to/2m4kMjs
Make sure your bike bag wheels are the same as the ones in the video before your order!