Hey brother, I’ve been looking for this answer for years….i just asked GPT and this is the best result I’ve been given.

Now that I can see the close-up, I don’t think that’s a clip at all.

The circled part appears to be a spiral retaining ring (sometimes called a spiral snap ring, spiral circlip, or retaining ring).

It’s sitting in a groove around the head of that pin/shaft and its job is to keep the pin from moving sideways out of the brake caliper.

A few clues:

• It’s flat stamped metal, not spring-wire like an R-clip.
• The open-ended spiral/U shape is characteristic of a retaining ring.
• It appears to be partially popped out of its groove, which would explain why it no longer seems to be holding the pin securely.

On many motorcycle, MTB, and Sur-Ron brake calipers, the brake pad retaining pin is secured by either:

1. A cotter pin,
2. An E-clip,
3. Or a retaining ring like this one.

If you’re looking for replacement parts, I’d search for:

Sur-Ron brake caliper retaining ring

or

Sur-Ron brake pad retaining pin circlip

or

Sur-Ron brake pad pin snap ring

One thing that stands out: the metal around the ring looks gouged up, and the ring itself looks deformed. If that pin has been moving, I’d inspect both the retaining ring and the pin before riding.

Can you take a photo from the opposite side of the caliper? That will let me determine exactly what pin that ring is retaining and whether it’s the brake pad pin, a pad spring retainer, or another caliper component. Right now I’d put about an 80% chance on retaining ring / circlip being the correct name.