Please explain brake master cylinders to me | GTAMotorcycle.com

Please explain brake master cylinders to me

Corsara

Corsara

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I just got a fly in my head that starting the season with just new Ferodo XRAC pads and new lines is not enough, and I should get a good MC to make use of that. So, I've been looking at the Brembos and the Accosatos that Bluestreakracing can get for me. All I know is that I should probably get the version with the folding lever to decrease the headache in the event of a crash. But I can't decide between the size, being 19x18 vs the 19x20, and the adjustable ones are more expensive. All I know is that the x20 will move more fluid and will feel stiffer, while the x18 will be somewhat more smooth but with more lever travel... Can somebody give me a more understandable explanation as to why exactly one has an advantage over the other, and we're speaking strictly about riding on the track, possibly one day racing, and no street riding at all. An added bonus would be why I shouldn't just get a Brembo OEM from an R6, but spend the extra dollars for an aftermarket unit.

Thanks in advance!

EDIT: Just extra info if that matters--I'll be keeping the stock 4-piston calipers that my 2003 gsxr 1000 comes with.
 
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The 18 and 20 refer to 18mm or 20mm piston offset.

18mm requires less lever effort but provides less feel. 20mm requires more lever effort but provides more feel.

Either would be a substabtial upgrade from stock and the difference between 18mm and 20mm is relatively small.
 
Corsara said:
I just got a fly in my head that starting the season with just new Ferodo XRAC pads and new lines is not enough, and I should get a good MC to make use of that. So, I've been looking at the Brembos and the Accosatos that Bluestreakracing can get for me. All I know is that I should probably get the version with the folding lever to decrease the headache in the event of a crash. But I can't decide between the size, being 19x18 vs the 19x20, and the adjustable ones are more expensive. All I know is that the x20 will move more fluid and will feel stiffer, while the x18 will be somewhat more smooth but with more lever travel... Can somebody give me a more understandable explanation as to why exactly one has an advantage over the other, and we're speaking strictly about riding on the track, possibly one day racing, and no street riding at all. An added bonus would be why I shouldn't just get a Brembo OEM from an R6, but spend the extra dollars for an aftermarket unit.

Thanks in advance!

EDIT: Just extra info if that matters--I'll be keeping the stock 4-piston calipers that my 2003 gsxr 1000 comes with.
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You can also call Tony at Bluestreak and ask him. He knows his products pretty well. He may also offer an insight between Accossato and Brembo from a value for money point of view.

For the record, I bought the adjustable Accossato from Tony but only because when Accossato started selling thru Galfer the adjustable was basically the same price as the standard one is now. An oversight that Galfer fixed fairly quickly!
 
caboose483 said:
The 18 and 20 refer to 18mm or 20mm piston offset.

18mm requires less lever effort but provides less feel. 20mm requires more lever effort but provides more feel.

Either would be a substabtial upgrade from stock and the difference between 18mm and 20mm is relatively small.
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Are you sure? Apparently not from personal experience, but I've read in a couple of places that 18mm needs less lever effort but provides MORE feel, 20mm is with the less feel but is stiffer and needs more effort. Maybe you accidentally used the wrong qualifiers? Sorry, just want to be sure what is what.

What are you guys running when racing? 18mm or 20mm?
 
caboose is correct. 19x18 has more travel, hence more feel. 19x20 has less travel and less feel (allows more fluid to pass through, so less distance on the lever is required to push the same volume of fluid through). Think of it this way, if you push a door closed near the hinge, harder to do, less travel, not as much feel. Push it closed near the handle, easier to do, more travel, better feel.

Neither choice is right or wrong. It's really just a preference. I have a brembo RCS that can be 19x18 or 19x20. I much prefer the 19x18 for feel. 1 finger will get the rear of an 08 CBR 1k in the air no problem. A friend, who is a former CSBK pro likes 19x20. Best bet is to find someone who has an RCS go for a test ride and see which is right for you. If not, in general i've found most people prefer the 19x18 for track use.

Like everyone else in the track world, I only have so much to spend. At first I gawked at the $300+ price tag for a brembo MC, said no way. How much better could it be? Then I tried one on a CSBK test ride and was sold in a heart beat. There are a few other vendors out there which also make MC's, and its close to the same price point. SS lines and motul 660 brake fluid (ask tony) are a must IMO. The CBR went from massive brake fade (thank goodness for the fabi runoff at SMP) to only a slight amount that was hardly noticeable. In the end, one of the best upgrades for sure. I would do brakes and suspension again before ever adding more power.
 
All this talk about brakes, reminds me of my first motorcycle ( okay mini bike ) built it myself with the help of my dads 5 horse briggs and straton roto tiller engine, built it but forgot one thing ( okay could not afford them and highly over rated) , brakes. So me and my buddy on his home build bike left the house and on our way to the trails to what is now the Gilkison Flats in West Brant, got stopped by the local cops, looked at our bikes, were impressed that we made them ourselves and that we had full gear on, helmet, gloves, long pants, boots and jacket. One of the cops asked if we had brakes, and I said yes, "foot brakes", they just shook there heads and told us to walk the bikes to the railway tracks and ride to the trails from there.
 
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caboose483 said:
18mm requires less lever effort but provides less feel. 20mm requires more lever effort but provides more feel.
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smergy said:
caboose is correct. 19x18 has more travel, hence more feel. 19x20 has less travel and less feel (allows more fluid to pass through, so less distance on the lever is required to push the same volume of fluid through). Think of it this way, if you push a door closed near the hinge, harder to do, less travel, not as much feel. Push it closed near the handle, easier to do, more travel, better feel.
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That's not what caboose wrote.

RobVN said:
http://www.ebay.com/itm/Brembo-Raci...Parts_Accessories&hash=item2c65e1ab76&vxp=mtr
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Great find Rob!
 
I saw at a place this:

"The evotech reservoir comes with a nipple for 6mm (Brembo size) and 8mm nipple for an oem sized hose."

Does it mean I have to get a new reservoir if I buy a brembo mc? Or my OEM is just fine?
 
yes, they are different sizes. if it's being used for the street, you'll also need to buy the brake light switch.
 
Corsara said:
I saw at a place this:

"The evotech reservoir comes with a nipple for 6mm (Brembo size) and 8mm nipple for an oem sized hose."

Does it mean I have to get a new reservoir if I buy a brembo mc? Or my OEM is just fine?
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It's a shame to buy fancy master and leave your giant hideous OE reservoir. With a brembo reservoir you can get away with 6 or 8mm tygon hose. 8mm will require clamps and/or safety wire. 6mm will fit so tight that you need to cut it to remove it, but most will safety wire or zip tie for redundancy.

I know its a little off topic, but consider it a public service announcement. Use Tygon tubing or equivalent only. Careful not to use other tubing. It can cause the fluid to go milky. I have actually had a racer come to me with brakes that failed due to this. The hose deteriorated from the inside out. a piece of the hose jammed the master, causing the brakes to go hard as a rock, but not apply any force to the pads. He managed to overrun the straight at GBM and used his rear brakes to stop safely.

Anyways. You want a cool little Brembo 15ml reservoir, a stainless ladybird bracket, and a piece of Tygon to connect it. Coincidentally I sell all 3. Shipped for 50$ tax in.

Shame on me for using a topic forum for advertising.... :D
 
thats what I thought you meant, I just read it wrong. And here I was thinking, wow, the 19x20 feels wooden to me
 
Brembo RCS master. Gives you the best of both worlds.
 
The rcs isn't rebuildable in N/A it has to go back to Italy, the standard ones can be rebuilt by yoyodyne in the US. I use a 19x18 on my gsxr 1000 and it works quite well for me, It's a personal choice but I've never tried a 20mm nor do I feel the need to change.
 
So, in terms of reservoir, brackets, tubing, banjo---what else exactly do I need to order if I go with the Brembo 19x18 or the Accosato 19x18 so that I have a complete package and not discover I'm missing something when I start installing it?
 
you've pretty much got it. master cylinder, tube, resevoir, brake light switch (street only, don't need this for track), banjo bolt, and some brake fluid. I suggest motul 660 if this is for the track. Be careful which brake fluid you use. You cannot mix dot 4 and dot 5.1. If you switch brake fluid types, you will need to fully clean your brake system which is a massive amount of work. Personally I would stick with a race rated dot 4 which is what motul 660 is , 5.1 feels spongy to me.
 
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