1. The problem statement, all variables and given/known data Hello. I'm working on a project here in Denmark, where we want to know which force, with which the brake pads on a mountain bike push against the brake disc, is needed to prevent the wheel from rotating. (the scenario is depicted here: http://imageshack.us/photo/my-images/522/mountainbikediscbrake.jpg/") We´re setting the coefficient of friction to μ=0,4 2. Relevant equations I know that we should use this equation: F=μ*N where N equals the force with which the brake pads pushes against the brake disc. We'll name it Fb. (N=Fb) 3. The attempt at a solution I'm not sure how to take in consideration that there is two brake pads pushing against the brake disc from both sides. My guess is that in this case the pressure delivered to the brake pads are equally distributed between the two brake pads. In this case the required force from each brake pad would be: F=μ*0,5Fb And the required force for both brake pads together (determined by which pressure is delivered to the caliber) would just be: F=μ*Fb Are these considerations correct or are there other factors to take in consideration when there are two forces pushing from each side. Does μ change ? does the surface area of the brake pads have anything to say? Thanks for reading, hope you can help me Greetings Kristian K. L.