Definition of an acid: a solution that reacts with metals.

Vinegar and lemon juice are both weak acetic acids. Maybe they will react with iron oxide more quickly that with chrome, but the game you will be playing is this: will my rust go away before my chrome (or nickel) gets ruined?

It may be that the backside of your wheels is nickel plating on top of copper plating, and the front side is copper-nickel-chrome plating. That does not look like bare steel in the photo.

(Chrome will not plate on steel but will plate on nickel. Nickel will not plate on steel but will plate on copper. Copper will plate on steel. That's why "chrome plating" is actually copper-nickel-chrome plating.)

I would not put acid on nickel or chrome except very carefully after experimenting. Personally I would try chrome polish on the backside first. Do no harm.