Robert Downey Jr. Malibu Biking with Son Indio in Safety-First Fashion

Robert Downey Jr.'s lookin' ready to hit the BMX circuit ... decked out in the proper attire for an afternoon bike ride -- and doing some father-son bonding complete with a loving fist bump.

The actor -- fresh off his first Oscar win -- rode down the Malibu coast Tuesday with his 30-year-old son Indio, and we gotta say ... RDJ made a loud statement with his athletic-chic fashion, one passing motorists were sure to see.

Check out the pics, Downey's going with highlighter bright colors ... a must-have while riding a bike on the mean L.A. streets, so drivers don't accidentally plow down an acting icon. He's also got his bike helmet on -- safety first, kids!

We're not gonna lie, Robert doesn't look totally comfortable in some of the pics from the seat ... but, he certainly seems to be enjoying himself when he gets a quiet second with his son -- smashing fist to fist in a sweet moment.

BTW ... seems like Indio doesn't share his father's style sense -- opting for a more toned-down black sweater. But, he's got his helmet on too, so it seems like Papa Downey might've won that argument.

Just to break down the family dynamic real quick ... Indio is Robert's son with his ex-wife Deborah Falconer whom he was married to from 1992 to 2004. He married his current wife, Susan, the following year, and they share two children: daughter Avri and son Exton.

Anyhoo ... seems like Robert's enjoying much-needed R&R after securing his first Oscar W -- taking home Best Supporting Actor for his role in "Oppenheimer" earlier this month.