Which brake system is this I have two brake systems I think on my bike. On the front I have a threaded stud and on the back a road brake.
Here is the front and the back (click for large version):


As you can see on the back the highlighted part is way smaller:

So am I right to say that on the front I have a threaded stud and on the back a road brake?
So am I right to say that on the front I have a threaded stud and on the back a road brake?

No
As Andrew says, you have v-brakes on the front and the rear.
Here's a picture from the front

V-brake pads come with a threaded stud and washers to allow you to adjust the angle of the pad and the distance from the arm to the pad.
The &quot;ball and socket&quot; design allows the angle of the pad to be adjusted.
The different thickness of the silver washers allows for two different possible distances between the brake arm and the pad.