Chris has it right!
Les Myer
At 01:36 PM 10/21/97 -0400, you wrote:
>Though I haven't done a conversion (yet), and assuming that I'm following
>this thread correctly, basic principles of hydraulics say you should be OK
>going from the 7/8 bore master cylinder to the 3/4.
>
>I'll try to explain. Let's say you have a small diameter cylinder hooked
>up to a large diameter cylinder, and let's say for convenience that the
>small cylinder is 1" and the large cylinder is 2". You stroke the small
>cylinder 1" by pressing on the brake pedal, exerting a force of 10 pounds.
> The big cylinder will move 1/2", but will exert a force of 20 pounds.
> Half the stroke, twice the force. Larger differences in diameter change
>the ratio upwards.
>
>The MGB calipers have bigger cylinders (also bigger pads) than the Midget
>calipers, hence with the same (7/8") master cylinder, more clamping force
>(and friction surface) on the brake disc, more stopping power for the same
>pedal pressure, at the price of a longer stroke (which might be okay if it
>gives you better "feel"). Going to the smaller (3/4") master cylinder,
>should make this effect more pronounced.
>
>Does any of this make sense, or did I jump a tooth on my mental timing
>chain?
>
>Chris Kotting
>ckotting@iwaynet.net
>
>
|