J
Jack Klarich
Guest
Changing hydraulic ratios -
Now that you know that, you can consider how changing the sizes of any of the pistons in the system will affect this relationship. Let's assume we've taken a standard braking system which works fine and for whatever reason, we are thinking of making the following changes.
Bigger master cylinder
If you increase the size of the master cylinder, you will actually be REDUCING the power of the brakes. Yes, with a bigger master cylinder, you will have to squeeze HARDER to get the same braking force at the calipers. This is because you are reducing the hydraulic advantage you have over the calipers. Crazy, right? Maybe but it's still a fact.
So why would anyone do this? Well, you will also be reducing the amount of lever travel needed to move the same amount of fluid, so if you've got very strong hands, or are on a race track and want/need shorter lever travel, then you might find it advantageous. Also, some bikes (t595, 600srad for example) are fitted from stock with what might be considered too small of a master cylinder, giving over-long lever travel, so some people like to upsize it to give a firmer, less vague feel at the lever. However if your bike as stock has good feel, then going up a size can make the brakes feel "wooden", that is, like an on/off switch. This happens when pulling the lever gently doesn't do much due to reduced advantage, but then with a tiny amount of lever stroke, that you have to squeeze hard potentially without finesse, you can very suddenly lock the wheel.
You'll be reducing the power of the master cylinder, so reducing the amount of flex generated through the system, as you'll now need to squeeze harder to flex the calipers than you probably can. This difference is often very noticeable while standing in the parking lot, but you won't necessarily feel this difference on the move, as if you're at that point of feeling flex from the brakes, you've probably already locked your front wheel.
Smaller master cylinder
If you decrease the master cylinder size, you actually GAIN in braking power due to the increased hydraulic advantage you gain. Brilliant, why don't we all do it?
Well, because you also increase lever travel. In some cases it's so bad that the lever hits the bar, maybe trapping your fingers before you stop hard. This is a Bad Thing! In some case, where the brakes as standard are "wooden", fitting a smaller master cylinder can improve them massively (xj600s) but if the brakes are already fine, you may end up with them feeling vague or spongy, or trapping your fingers.
You can sub bigger master for smaller calipers, or vice versa, and the principles will hold.
I found this to be an interesting read
Now that you know that, you can consider how changing the sizes of any of the pistons in the system will affect this relationship. Let's assume we've taken a standard braking system which works fine and for whatever reason, we are thinking of making the following changes.
Bigger master cylinder
If you increase the size of the master cylinder, you will actually be REDUCING the power of the brakes. Yes, with a bigger master cylinder, you will have to squeeze HARDER to get the same braking force at the calipers. This is because you are reducing the hydraulic advantage you have over the calipers. Crazy, right? Maybe but it's still a fact.
So why would anyone do this? Well, you will also be reducing the amount of lever travel needed to move the same amount of fluid, so if you've got very strong hands, or are on a race track and want/need shorter lever travel, then you might find it advantageous. Also, some bikes (t595, 600srad for example) are fitted from stock with what might be considered too small of a master cylinder, giving over-long lever travel, so some people like to upsize it to give a firmer, less vague feel at the lever. However if your bike as stock has good feel, then going up a size can make the brakes feel "wooden", that is, like an on/off switch. This happens when pulling the lever gently doesn't do much due to reduced advantage, but then with a tiny amount of lever stroke, that you have to squeeze hard potentially without finesse, you can very suddenly lock the wheel.
You'll be reducing the power of the master cylinder, so reducing the amount of flex generated through the system, as you'll now need to squeeze harder to flex the calipers than you probably can. This difference is often very noticeable while standing in the parking lot, but you won't necessarily feel this difference on the move, as if you're at that point of feeling flex from the brakes, you've probably already locked your front wheel.
Smaller master cylinder
If you decrease the master cylinder size, you actually GAIN in braking power due to the increased hydraulic advantage you gain. Brilliant, why don't we all do it?
Well, because you also increase lever travel. In some cases it's so bad that the lever hits the bar, maybe trapping your fingers before you stop hard. This is a Bad Thing! In some case, where the brakes as standard are "wooden", fitting a smaller master cylinder can improve them massively (xj600s) but if the brakes are already fine, you may end up with them feeling vague or spongy, or trapping your fingers.
You can sub bigger master for smaller calipers, or vice versa, and the principles will hold.
I found this to be an interesting read