04-25-2012, 05:31 AM
The numbers refer to millimeters - the first number is the bore diameter size (area that pushes the fluid), the second number is the pivot distance between the pistons push rod center and the pivot center.
The main difference in master cylinder size as it relates to our use:
- 19 and 20 mm masters are typically used to drive (2) four piston calipers
- 16mm are typically used on a singe four piston caliper (some bikes only have 1 disc)
- 13mm is typically used on a one or two piston caliper
This is due to the amount of fluid that the master's bore is designed to move to the calipers.
What does this mean to us? well, for handbrake purposes, you would match the master size to the handbrake caliper size as appropriate or choose a different size based on the feel that you are looking for.
i.e. A Large master used on a small caliper will have a very hard feel with little lever travel as it is trying to move a lot of fluid and has nowhere to move it to. Conversely, if you used a 13mm master with a four piston caliper, you will have a very soft lever with lots of travel (which some may like better as more variable control).
The main difference in master cylinder size as it relates to our use:
- 19 and 20 mm masters are typically used to drive (2) four piston calipers
- 16mm are typically used on a singe four piston caliper (some bikes only have 1 disc)
- 13mm is typically used on a one or two piston caliper
This is due to the amount of fluid that the master's bore is designed to move to the calipers.
What does this mean to us? well, for handbrake purposes, you would match the master size to the handbrake caliper size as appropriate or choose a different size based on the feel that you are looking for.
i.e. A Large master used on a small caliper will have a very hard feel with little lever travel as it is trying to move a lot of fluid and has nowhere to move it to. Conversely, if you used a 13mm master with a four piston caliper, you will have a very soft lever with lots of travel (which some may like better as more variable control).