2010 Prius makes ticking noise

No idea on Prius-specific explanations, but from actual experiences on different cars:

1. sometimes the gap between wheel balancing weights on the inside of the rim and the brake caliper is a very narrow gap. And sometimes with sloppy weight balancing, there may be a slight contact once per revolution. Can be barely a touch, perhaps light brake pressure would be enough to make the contact occur.

2. much simpler (different car) - sometimes a tiny pebble would get stuck in between the wheel cover and the wheel. Normal centrifugal force would hold it in place, but at low enough speeds it would make some noise. Also once had a similar thing *inside* the wheel/tire due to sloppy installation of custom wheels (different car) - there was a loose part in the inflated air gap within the wheel. The tiny part (nut?) would stay flung to the inside surface of the rim due to centrifugal force when driving, but when slowing to about running speed, it would bounce and rattle around within the wheel.

3. The wheel cover would sometimes get flexed by the tire at slow speeds making a slight creaking / ticking noise.

Just some ideas. It could be the removal and reinstall of the wheel covers, or maybe there is tight clearance with the inside rim.

Moving things around is a fundamental trouble shooting step that can find many problems.

 

Pebble stuck in tread? If rotated from front to back it'd become less audible.

If you're DIY rotating it's a good opp to straddle and slowly roll the wheel, looking for and prying out stuff stuck in the tread. Wear safety glasses when doing this.

 

Only happens when braking and only during regeneration.