I have a set Shimano Tiagra 4700 levers/shifters on my Niner gravel bike (RLT 9 1 Star) and lately I noticed when moving forward, at speed or slow, there is a subtle click when pulling on the left side lever for the front disc brake -- no matter how light I pull. If it's of any relevance, the brakes on this bike are the stock SRAM BB5 Mechanical disc, Road version, 160mm Avid rotors. The bike is new (just picked it up May and I have about 210 miles on it). I'm not noticing any effect on braking performance but just wondering if this might be a potential problem.
I noticed this after going on a somewhat long ride a few weeks ago with moderate bumps, paved and unpaved as well as loose gravel surfaces. Could this be debris or sediment trapped somewhere in the components? I'm not all that familiar with disc brakes yet so any ideas/suggestions would be greatly appreciated!
Edits from comments:
The lever is quite solid on the handbars and no wobble at all.
The click seems to depend on forward motion while riding. I've tried to replicate it by turning the bike upside down, then spinning the wheel and pulling on the brake lever -- no click, even if the wheel is spun backwards.