I own a mountain bike with mechanical disc brakes that seriously lack stopping power. I've tried tweaking things and replacing pads but always fell short on performance. I ride more on the road but sometimes offroad. I was just wondering: Does a fluid for making disc brakes "grab" better exist?
Not that I have ever heard of. Any liquid on the rotor or pad would tend to act as a lubricant and get worn or washed off anyway.
Mechanical or hydraulic brakes ?
If mechanical, maybe the cables are not tight enough ? or too used ? If hydraulic, maybe there's a leak in the system ?
In both cases, maybe the pads are too worn out ? maybe the brakes rotors themselves are dirty or worn out or have some oil/grease/dirt on them, clean them out.
Have a looksie at :