Which size Brembo Radial Master gives the best feel?

This seems to get tossed around a bit... I'm getting one and wanted to see what the preferences were...

I'm leaning to the 19X20, as it seemed to have a firmer feel and less travel. What do you all think?

The current aftermarket 19mm diameter master cylinders offer you the choice of a brake lever fulcrum-to-piston distance of either 18mm or 20mm. The stock Brembo lever (for dual rotor bikes) has a 16mm dimension.

This different geometry means that the stock lever will need a lower pull force over a longer pull distance than the other two aftermarket MC’s to yield the SAME stopping power.

The 18mm lever will require 11% less pull force than the 20mm lever, but it also needs to be pulled through an 11% longer lever distance to get the same stopping force at the calipers. Conversely, with the 19X20 MC, you need to apply the highest pull force, but need the least lever movement to get the same amount of braking.

Some riders think that this short-pull trigger action means that they have "better" brakes, but they don't - at least not for all riding conditions. What they do get is the same braking power with poorer modulation (feel) characteristics. Good for the track perhaps, but often dangerous on the street, especially in the wet. In an emergency, most of us have the instinct to grab a brake hard. So if you value a better feel, when choosing between the 19X18 and the 19X20 for the street, go for the 19X18.


Modified by Shazaam! at 11:45 AM 10/17/2004

So is the stock MC a 19x16?

Well said Shaz!

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Shazaam! &raquo;</TD></TR><TR><TD CLASS="quote">
What they do get is the same braking power with poorer modulation (feel) characteristics. Good for the track perhaps, but often dangerous on the street, especially in the wet. In an emergency, most of us have the instinct to grab a brake hard. So if you value a better feel, when choosing between the 19X18 and the 19X20 for the street, go for the 19X18.
Modified by Shazaam! at 11:45 AM 10/17/2004</TD></TR></TABLE>

Sorry I disagree. I think it is exactly opposite. First feel is totally subjective so who are you to tell ME what feels better? Second grabbing TOO MUCH front brake is much more likely to happen if the pull is soft then if it is hard your own arguments hang you.

Alex, I'm not suggesting that every rider has the same preference in a braking system's modulation characteristics. Depending on your preference (or need) you can have brakes with an initial vague feeling, a strong initial bite, or something in between. You can select pads that have better high temperature behavior. On a race bike you can select brake pad and rotor material that will survive a race without needing replacement, but on the street, materials need to be more durable and function under less severe braking conditions and more varied weather conditions.

When you first ride a new bike, you have an expectation: the harder you pull on the brake lever, the faster you will stop. If you've ever locked-up the brakes on an unfamiliar bike when you've first applied them, was your initial thought that they were great brakes?

A braking system needs to establish the closest linear relationship possible between the force applied to the brake lever and the actual deceleration of the bike. Stopping power is technically easy to achieve, but achieving it along with good proportional braking response is very complex. This, I feel, is the major factor influencing braking quality.

For example, it is of fundamental importance for braking safety and performance that the rider should know, in advance, that a force of 500 grams on the brake lever will give a certain deceleration of the machine, and that a force of 1,000g will result in twice the deceleration, regardless of the conditions (beginning or end of braking, hot or cold, dry or wet).

So, often the advantage of upgrading a braking system is not only greater power. The improvement in proportional response is equally important, as it allows the rider to control and gauge the braking power that's applied, as a function of the conditions of adhesion (grip). This represents a considerable improvement in safety on both road and track.

Nevertheless, any rider IS able to compensate for one performance drawback to gain an advantage with another. But again, it's situational dependent; a braking system that gives repeated stops from 150 mph with the force application of one finger is not necessarily optimum for a 40 mph panic stop in traffic. Even though a rider is adapted to a braking system's general behavior doesn't mean that in an emergency that he'll use a light one-finger pull to stop.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Shazaam! &raquo;</TD></TR><TR><TD CLASS="quote">

The current aftermarket 19mm diameter master cylinders offer you the choice of a brake lever fulcrum-to-piston distance of either 18mm or 20mm. The stock Brembo lever (for dual rotor bikes) has a 16mm dimension.

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To give a better point of reference, what is the piston diameter of the OEM Brembo Goldline master cylinder?



Modified by infoage1 at 8:18 PM 10/17/2004

Get the Brembo 19x16 Billet Master Cylinder and you will have no regret.

Hey Rob, how's it going? Haven't spoken with you since the Pridmore school last month, good to meet ya and I had a great time out there with the California boyz.

Here's my experience. My 748r came with regular gold-line calipers. After upgrading to the 19X20, the brakes worked pretty good. Later I upgraded the brakes to 4-pad calipers and after quite a few scary braking moments, I decided I wasn't going to get used to the "feel" required with the 19X20. I switched to the 19X18, had no problems afterwards and forever more I am in love the brakes on my Duc. I guess I'm one of the ones that likes to have both lever travel and pressure to brake consistently. But as you know, I’m not exactly a threat to track records out there.

For my Kawi I would try the 19X18, but this is just my opinion.

I have the Brembo 16 billet master. I have used it on the R1 & Ducati. I thought the 16mm is for the single caliper set-up and the 18 & 20 are for the dual calipers set-up. So I went and bought the 19x20 for the duc. Can I still use the billet 16 on the dual set-up? Somebody shed some light on this. Thankx

I recently upgraded the OEM goldline MCs on my 900SS to the Brembo semi-radials from the 999/Aprilia Factory (same difference). Not sure off the top of my head what ratios these MCs have, but the power was noticibly improved compared to the OEM Brembo Goldlines, and feel seems better too, but at the same time I haven't had enough seat time to make any strong comment on the difference. I need little more than 2 fingers to brake (OEM pads and rotors), which for a fair weather rider like myself seemed like a good thing until I read Shaz's post which made me think about the off chance I find myself riding in the wet and some a-hole takes a left in front of me.

I have the Brembo 16 billet master. I have used it on the R1 & Ducati. I thought the 16mm is for the single caliper set-up and the 18 & 20 are for the dual calipers set-up. So I went and bought the 19x20 for the duc. Can I still use the billet 16 on the dual set-up? Somebody shed some light on this. Thankx

What do you have exactly? Billet 16X? or Billet 19x16? If you have Billet 19x16, that should work on dual rotors. If you have Billet 16x?, then that is for single rotor.

"What do you have exactly? Billet 16X? or Billet 19x16? If you have Billet 19x16, that should work on dual rotors. If you have Billet 16x?, then that is for single rotor"

Not sure which model Brembo billet master cylinder I have, top just has a stamp "16" while bottom is stamped "8613 19"

It should have a diameter sign after the number. So whatever that number is, that's the size of the piston.

Must admit I'm a little confused with some of the posts on the effects of the diameter vs feel. The smaller diameter pistons will increase hydraulic advantage and thus power, with relatively more lever travel and less lever effort.

The larger diameter piston decreases braking power, by reducing lever travel but with increased lever effort required.

The key here is, what is easier to control - the more powerful braking with lighter lever feel and more lever travel provided by the smaller piston, or the firmer lever feel with less braking power provided by the larger piston?

My initial assumption was also that the additional lever travel of the smaller piston setup would provide more rider feedback and ability to modulate the brake at the edge of traction loss (or terminal stoppie point) - BUT many guys that I've spoken with about this feel that the firmer lever and reduced braking power of the larger piston setup provides easier rider control despite the reduce lever travel.

I guess for many, it's not the amount of lever travel that's important, but the firmness of the lever feel?

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Old Baldy &raquo;</TD></TR><TR><TD CLASS="quote">The smaller diameter pistons will increase hydraulic advantage and thus power, with relatively more lever travel and less lever effort.

The larger diameter piston decreases braking power, by reducing lever travel but with increased lever effort required.

The key here is, what is easier to control - the more powerful braking with lighter lever feel and more lever travel provided by the smaller piston, or the firmer lever feel with less braking power provided by the larger piston?

I guess for many, it's not the amount of lever travel that's important, but the firmness of the lever feel?</TD></TR></TABLE>


Exactly correct. First off it is subjective what I like you might not. In my experience it has been easier for me to MODULATE pressure then to control the pull distance. The firmer pressure required registers in my brain where pulling another 1/2 inch doesn't. Remember that the leverage ratios make a difference too. Brembo's 19x20 and 19x18 can be compared without any math but how does that compare to a 16x16? You need to do the appropriate math to figure it out.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by Rrider &raquo;</TD></TR><TR><TD CLASS="quote">Hey Rob, how's it going? Haven't spoken with you since the Pridmore school last month, good to meet ya and I had a great time out there with the California boyz.

Here's my experience. My 748r came with regular gold-line calipers. After upgrading to the 19X20, the brakes worked pretty good. Later I upgraded the brakes to 4-pad calipers and after quite a few scary braking moments, I decided I wasn't going to get used to the "feel" required with the 19X20. I switched to the 19X18, had no problems afterwards and forever more I am in love the brakes on my Duc. I guess I'm one of the ones that likes to have both lever travel and pressure to brake consistently. But as you know, I’m not exactly a threat to track records out there.

For my Kawi I would try the 19X18, but this is just my opinion.</TD></TR></TABLE>


Thanks for the feedback, Gary! I like very little lever travel, and also have tried my best to get the stock brakes as firm as possible. It sounds like the 19x18 might have too much lever travel and give up the sensitivity I'm looking for... That's if I'm reading all of this right!

BTW, you looked plenty fast out there at STAR!

Shaz... The brakes are for track use only, as I don't have a streetbike... Either way, I'd agree 110% with Alex. Street or track, it's safer IMHO to have a braking system capable of stopping asap vs. some kinda built-in fool's cushion to protect me from myself.

When I talk about feel, it's all about using pressure to modulate braking resources, not lever travel. To me, the more distance the lever travels, the more I'm sacrificing in 'feel'. Other riders might find the lever travel very important in gauging the amount of brake force they want to apply.... Those folks might be more concerned with 'power'. Since I can change the bite characteristics with pads and the such, I'm really looking for a braking system which will increase the lever feel and reduce the distance the lever needs to travel.

<TABLE WIDTH="90%" CELLSPACING=0 CELLPADDING=0 ALIGN=CENTER><TR><TD>Quote, originally posted by 908SSP &raquo;</TD></TR><TR><TD CLASS="quote">Exactly correct. First off it is subjective what I like you might not. In my experience it has been easier for me to MODULATE pressure then to control the pull distance. The firmer pressure required registers in my brain where pulling another 1/2 inch doesn't. Remember that the leverage ratios make a difference too. Brembo's 19x20 and 19x18 can be compared without any math but how does that compare to a 16x16? You need to do the appropriate math to figure it out. </TD></TR></TABLE>

while personal experience is EXTREMELY helpful (and thanks ...er from all probably) It is also important to note, that your brain, but many/not all-fine motor skillls are the same or are utilized in track "depth" situations.....and they are not the same. While, most of us here/ or anywhere - don't likely have the free and open option to ride "our" bike with different brake and clutch masters/levers, its great to have other's feedback,

while i understand i am a new 998 owner...and a past RC51/worked over RC51 rider....my stock 998 fronts have some incredible initial power.....and the RC51 stock stuff...is pretty much great without exta attention other than braided lines and mayber HRC pads.

My 998 rear brake though, couldn't stop me from rolling down a slight incline at a light right now I'll bleed and report
where the RC51 rear....(bad) when bled correct/ Would lock up with bare foot love
not healthy......intentionally letting air into the line was the solution with that world