Wheel nut Question.

Do I need different wheel nuts if I change from steel wheels to alloys?
If so.Will this affect my locking nut?

 

It will depend on the alloy wheels you choose, OEM alloys use the same nuts as the OEM steel wheels.

Take one of your lug nuts off, it can be one holding the spare, and examine it, you'll see it has a taper that fits into a matching taper on the wheel rim - this is what is known as "lug centric", the taper of the lug nuts centers the wheel on the hub.

Some alloy rims are hub centric and these need hubs with a protruding "spigot" and either the wheel center bore is a close fit to the spigot or you fit a "centering ring" to center the wheel on the spigot. This style of rim will have a flat seat where the nut sits, and these need a "shanked" nut with a washer to clamp the wheel to the hub.