Practically Classics Forum

which paint is best used on a hard plastic old steering wheel.?

Epoxy based paint is by far best if the rim is made from a powdered resin such as Bakelite. For later, synthetic plastics, use an enamel - such as Rustoleum - from an airgun if you have such a thing, or from a rechargeable aerosol if not.
Important thing in either case is the surface prep, as the best paint in the world won't look much if the filling and priming are skimped or rushed through.

What is the car and can we see a picture of the wheel please?

1970 range rover

Now pictures are definitely needed! We need another couple of RR owners one with a late 2 door and one with an early 4 door on carbs and we'll have the set.

one of them ,I think the grey is wrong ,needs to be darker .

Is that grey a result of exposure to light or has someone painted that wheel in its past?
If it has faded it's definitely a modern, synthetic plastic such as polystyrene or ABS. A quick web search for "Retrobright" will explain how, using a mixture of some things that are almost always present in a kitchen, these plastics can be freshened up massively and that may be enough but, if you need to paint the wheel, then enamel, thinned by >50%, will be the smoothest way to go. Each coat will need a day to harden sufficiently to consider giving it another coat, so it is a slow process compared to using acrylic paints, but will ultimately be both harder and smoother than any modern paint.
If the wheel rim has nibbles, deep scratches or is down to the wire at any point, then use Miliput or a similar polystyrene-based filler to build up the shape. In the event of there being any cracks that appear to be more than skin deep (IE, when the parts at either end of the crack are moving relative to each other), then grind down until you reach solid plastic or the rim wire and build up with the modelling putty/filler to shape. A profile gauge is worth using on this sort of task and will have other uses - automotive and household - after the wheel job is finished.

its been painted in the pasted .

now this one is the right colour ,I repaired it , cracks etc, primed just need the right top colour .