Originally Posted by
Koyote
I understand what the two of you are talking about… I just think you’re both wrong.
Please note that you have now told two of us that we don’t understand your arguments. So, perhaps the problem is not with us...?
What exactly do you think we are wrong about?
The leverage ratio (between the brake lever and caliper pads) is much higher in a disc brake system than a rim brake system. This means that the disc pads move less distance over the throw of the lever, but exert greater force on the rotor. This is a simple fact. Do you think I am wrong about that?
WHY do you think that is? Two reasons.
First, it NEEDS to be, because the disc itself has much less leverage over the wheel. The disc caliper MUST exert more force than the rim claliper in order to achieve the same stopping force. Do you disagree with that?
Second, it CAN be designed to have greater leverage over the pads. Take a look at how far your disc brake pads move when you pull your lever all the way. Maybe 0.5 mm? Maybe less? Now look how far your rim brake pads are from your rims. They are much farther away. If your rims brakes had the same leverage over the pads as your disc brakes, you would pull the lever all the way to the bar and never get the pads to hit the rim. Do you disagree with this?
What part exactly do you think I am wrong about?
Think about this: why don't they design rim brake calipers and levers so that the levers have MORE leverage over the pads than they do now? More leverage would make stopping easier, so what don't they do it? The answer to that is the very point I was making.