Justin Bieber Poses by New Drew Motorcycle for Hailey

Justin Bieber might be going through a mid-20s crisis -- first, he's challenging Tom Cruise to a fight out of the blue ... now he's gifting himself a fancy new crotch rocket.

At least he's got a loving Instagram wife by his side.

The Biebs got a brand new motorcycle delivered to his home Tuesday, wrapped in the brand name of his new Drew clothing line ... and Hailey snapped some quality pics of her hubby for the 'gram.

The 2-wheeler also features his favorite number, 6 ... as if it's going to be entered in some sort of race.

Wouldn't put it past JB.

As we reported ... Justin surprisingly challenged the famed 56-year-old actor to an MMA fight this past weekend and enlisted Dana White to set it up. His motive for beefing with Cruise is still unclear.

Also unclear ... whether or not Justin took Hailey for a spin on his new hog. Either way ... their photo shoot was a success.

Hailey captioned the final product, "Boys and their toys," followed by 3 eye roll emojis. That seems about right.