What is rail match?
Rail match is when the edges of your wheels are in line with the edge of the board where you put your feet (standing platform)
Generally, if the rails of the board (edges) are straight, if you can rest a board sideways on its wheels and rail, the board can be considered rail matched.
Generally, riders tend to chase after the perfect rail match as it tends to feel agile while not feeling tippy.
How do I get rail match?
There are a few factors that affect rail match.
1. Hanger width
If you have wider hangers, the distance edge to edge on the wheels will be larger.
If you have smaller hangers, the distance edge to edge on the wheels will be smaller.
2. Deck width
If you have a wider deck, the distance edge to edge on the wheels will need to be higher to obtain rail match.
If you have a narrower deck, the distance edge to edge on the wheels will need to be narrower.
3. Wheel offset and dimensions
A wider wheel will make the distance edge to edge on the wheels higher. A narrower wheel will make this distance smaller.
A wheel with a higher offset will make the distance edge to edge on the wheels higher compared to a lower offset.
When you aren't rail matched
Wheels wider than the deck
Commonly called: Wheel overhang, poke
Generally, this is avoided. It is present on older longboard trucks, as the science behind the geometry was not as advanced.
It is commonly believed to feel more stable, but it is actually less responsive and agile. Turning will require more effort.
Wheels narrower than the deck
Commonly called: Deck overhang, tuck
This is also generally avoided, but some people do have deck overhang as a personal reference.
This will make the board feel a lot more responsive, however it is sacrificing some ability to return to center. Because of this, the board will feel tippy. Turning will be much easier.