Re: Disc brake tuning

On 2/5/24 23:03, AMuzi wrote:

 For a cable disc, I'd double check wire/casing and, with the cable disconnected, ensure the lever/cam returns smartly. The pad return spring is just not significant to pad return force.

Indeed the only purpose of the pad return spring is to keep the pad backing plate in contact with the piston face when the brake is not applied, to avoid the pads rubbing.
The problem is that the spring doesn't always press the backing plate squarely against the piston face.  Allowing the backing plate to be at an angle to the piston face while the brake is not applied, the pad is also then not held in a parallel plane to the disc - until you apply the brake of course.  Hence there is additional movement required by the piston and lever before the brake is properly applied.
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JS