Next project, front Brembo's
Road Captain
Joined: May 2014
Posts: 618
Likes: 100
From: MA
The master also has a play in lever feel. On my bike I used calipers off a Yamaha R6. Not a blingy as the Brembos. I believe the pistons in them are 30mm and 27mm. Can't say 100% though. I am also using a Brembo 19RCS for my master. I have a very firm lever.
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Stellar HDF Member
Joined: Aug 2019
Posts: 3,120
Likes: 1,906
From: Unreconstructed
I think the 19RCS is an 11/16th bore like the MoCo one I have on the bike, which is one of the reasons I am looking at the 30mm bore calipers. I reached out to SpeedKings to see if they can get me a set and if they can I'm going that route.
Road Captain
Joined: May 2014
Posts: 618
Likes: 100
From: MA
It is not only about the bore size. How it delivers the fluid and the quality of the components make a difference. I'm certainly no expert on brakes but I do know where I ended up with some previous experience and some trial and error. One thing the RCS has is an adjustable ratio. Just something else to throw out there. There is a bit more work involved to get it 100% functional such as figuring out where you put the reservoir and the brake light switch depending on year. Might not be a bad idea to see if you can find someone nearby that has one. I am about an hour from Boston, MA if that makes any difference.
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Stellar HDF Member
Joined: Aug 2019
Posts: 3,120
Likes: 1,906
From: Unreconstructed
It is not only about the bore size. How it delivers the fluid and the quality of the components make a difference. I'm certainly no expert on brakes but I do know where I ended up with some previous experience and some trial and error. One thing the RCS has is an adjustable ratio. Just something else to throw out there. There is a bit more work involved to get it 100% functional such as figuring out where you put the reservoir and the brake light switch depending on year. Might not be a bad idea to see if you can find someone nearby that has one. I am about an hour from Boston, MA if that makes any difference.
I am going to convert my stock dual front disc setup to Brembo calipers and have some specific questions for those that have previously done this.
Specifics, 2017 cammed 103, RaceTech +2 front suspension, Legends rear. I am looking for better feel and modulation up front. Very little long-distance riding, mostly around town and blasting around here and there.
Specifics, 2017 cammed 103, RaceTech +2 front suspension, Legends rear. I am looking for better feel and modulation up front. Very little long-distance riding, mostly around town and blasting around here and there.
- M4's or GP4's?
- Best radial mount? Looking at TC Bros right now
- "Ideal" rotor diameter?
- Can I leave the stock rotors now and size up later by shimming the caliper bracket?
- I am running the OEM 11/16 master, that should be fine right?
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Stellar HDF Member
Joined: Aug 2019
Posts: 3,120
Likes: 1,906
From: Unreconstructed
I'll be going with the M4s since I'm already running one in the rear. I bought the Speed Merchant brackets because that is what was recommended to me by someone I trust. I don't think it matters to much though. Those have just been around a while. Originally I bought a bagger brembo master but after the last thread about this I found out it is only a 15mm so I'll be selling that and have decided to go with the RCS master. (The 11/16 mc will do the job though) Elite Mototech makes a matching lever for it to match my easy pull clutch lever from them also so that's a huge plus. I also have 14" rotors and the calipers will have to be spaced out accordingly. I can't say from a legitimate technical standpoint that that is okay to do but I see it on just about every bike that has this type of setup and I've never heard anyone say it's unsafe to do. I will be having solid spacers made instead of stacking washers however.
Last edited by snake_eyes; Jun 26, 2023 at 01:46 PM.
Hey man, I was hoping you'd find your way to this thread. I looked at the SM brackets but don't like the way they cover so much of the rotor so I'm going with the Rebuffini brackets. Same here on spacers, I am seeing a lot of that out there, one of the brackets I saw actually said something like "if you already have the smaller brackets, you can buy our shims to fit a larger disc", I dunno but I'm going to stick with the 11.8's for now and regret it later, I guess. There are my winter projects to keep my sanity so if I do it all at once it would ruin winter '24 plans.
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Road Captain
Joined: May 2014
Posts: 618
Likes: 100
From: MA
When you guys get your M4 calipers just be sure they have the correct bolt spacing for the brackets you are using. The stuff of the euro bikes is 100mm bolt spacing and a lot off the Japanese bikes is 108mm bolt spacing. I know the speed merchant stuff is 108mm. They were designed to work with the calipers off the GSXR. Back when I did all this which seems like a million years ago now they were the only ones on the market that were complete and easy to get. I ended up using calipers off an R6. Since then Yamaha has started using Brembos on their R6 but I don't exactly know which model or bolt spacing. Pretty sure its 108mm. Just something to be aware of if you are going to used route. I just gave away a pair of M4 calipers that were 100mm spacing.
As for going with larger brake rotors. The great thing about the radial mounts is you can do that later. When I first started swapping parts out I just reused the stock rotor. I was going only single disc at the time. After riding that a bit I decided I wanted to go dual disc. I already had the right side bracket and caliper ready to go so it was only a matter of getting a second disc and a different master. The brackets I had were for the 11.5in/292mm disc. I moved to a set of 320mm rotors from Braketech. Just had to fab up larger spacers and buy some longer bolts. If larger rotors aren't in the budget now its an easy conversion later.
The master is an easy upgrade later. Ride what you have and decide if you like it before spending the money. I understand what you mean about the look. As it stands now I have one chrome lever and one black lever on my bike. Doesn't really bother me but I know it's there.
As for going with larger brake rotors. The great thing about the radial mounts is you can do that later. When I first started swapping parts out I just reused the stock rotor. I was going only single disc at the time. After riding that a bit I decided I wanted to go dual disc. I already had the right side bracket and caliper ready to go so it was only a matter of getting a second disc and a different master. The brackets I had were for the 11.5in/292mm disc. I moved to a set of 320mm rotors from Braketech. Just had to fab up larger spacers and buy some longer bolts. If larger rotors aren't in the budget now its an easy conversion later.
The master is an easy upgrade later. Ride what you have and decide if you like it before spending the money. I understand what you mean about the look. As it stands now I have one chrome lever and one black lever on my bike. Doesn't really bother me but I know it's there.
When you guys get your M4 calipers just be sure they have the correct bolt spacing for the brackets you are using. The stuff of the euro bikes is 100mm bolt spacing and a lot off the Japanese bikes is 108mm bolt spacing. I know the speed merchant stuff is 108mm. They were designed to work with the calipers off the GSXR. Back when I did all this which seems like a million years ago now they were the only ones on the market that were complete and easy to get. I ended up using calipers off an R6. Since then Yamaha has started using Brembos on their R6 but I don't exactly know which model or bolt spacing. Pretty sure its 108mm. Just something to be aware of if you are going to used route. I just gave away a pair of M4 calipers that were 100mm spacing.
As for going with larger brake rotors. The great thing about the radial mounts is you can do that later. When I first started swapping parts out I just reused the stock rotor. I was going only single disc at the time. After riding that a bit I decided I wanted to go dual disc. I already had the right side bracket and caliper ready to go so it was only a matter of getting a second disc and a different master. The brackets I had were for the 11.5in/292mm disc. I moved to a set of 320mm rotors from Braketech. Just had to fab up larger spacers and buy some longer bolts. If larger rotors aren't in the budget now its an easy conversion later.
The master is an easy upgrade later. Ride what you have and decide if you like it before spending the money. I understand what you mean about the look. As it stands now I have one chrome lever and one black lever on my bike. Doesn't really bother me but I know it's there.
As for going with larger brake rotors. The great thing about the radial mounts is you can do that later. When I first started swapping parts out I just reused the stock rotor. I was going only single disc at the time. After riding that a bit I decided I wanted to go dual disc. I already had the right side bracket and caliper ready to go so it was only a matter of getting a second disc and a different master. The brackets I had were for the 11.5in/292mm disc. I moved to a set of 320mm rotors from Braketech. Just had to fab up larger spacers and buy some longer bolts. If larger rotors aren't in the budget now its an easy conversion later.
The master is an easy upgrade later. Ride what you have and decide if you like it before spending the money. I understand what you mean about the look. As it stands now I have one chrome lever and one black lever on my bike. Doesn't really bother me but I know it's there.