It has been a few years since I changed my wheels!
I bought this pack of wheels from Amazon. It includes everything you need - wheels, bearings and spacers.
Make sure you get the right parts as there are different sizes of wheels and different kinds of bearings and spacers. The wheels I bought came with the wrong spacers so I had to reuse my old ones.
Find an allen wrench that fits and unscrew the axel.
Use the allen wrench to poke the axel out through the wheel.
Repeat this for the rest of the wheels. I like to screw the axel parts back together so they don't get mixed up and are harder to lose.
Yeah, these needed to be changed badly.
If needed, remove the old bearings to get the spacers. There is a special tool for this but I could not find mine. A screwdriver works in a pinch. Rock and pull the screwdriver to get the bearing off.
Spacers have been liberated!
Use a screwdriver to poke out the new bearings so you can replace the spacers.
To put the wheels back on, start by putting the axel back in. There is a groove the axels sit in so they can't spin so turns the axels a bit until they pop in to the groove.
Now put the screw cap on the axel and tighten. The wheels should spin freely as you tighten the screw.
Now repeat seven more times! Pro tip: keep the labels on the wheels all facing the same way - I keep them outward. This makes it easer to keep track of things when you rotate them later.
And you are done! Have fun and be safe!