Fleetwheel Cruiser comes from a line of cards going all the way back to Ball Lightning, somewhere between a conventional creature and a direct damage spell. While it's arguably less strong on its own than some other cards of that line due to being an artifact as well as a creature and needing other creatures for its second and subsequent attacks, the fact that vehicles got some pretty good support in Kaladesh helps make up for that. Its crew cost also makes a good use for early creatures that find themselves weaker than your opponent's mid-game blockers.
 
Constructed: 4/5
Casual: 4/5
Limited: 4/5
Multiplayer: 4/5
EDH/Commander: 4/5

Fleetwheel Cruiser (1/6)
 
The best way to get around the Vehicle drawback, besides printing one that's so efficient it's almost obscene (Smuggler's Copter), is to print one that animates and smashes face on the same turn. It's surprisingly well-costed: 4 mana for a 5/3 with trample and haste, that can attack the turn it drops without needing other creatures, is just nasty. It's seen play in Legacy and Vintage, which should tell you how powerful a Vehicle that dodges the usual Vehicle drawback, at least on its first turn is.
 
Even after it's on board, the crew cost (2) is low enough that it can be used again. And even if it dies, it likely took a planeswalker or a huge chunk of your opponent's life with it. This is the rare card that shines more in non-rotating formats.
 
Constructed: 4
Casual: 4
Limited: 4.75
Multiplayer: 3
Commander: 3.25