The Obtainable Brembo GP4-MS, GP4-RR, GP4-PR, GP4-RS, GP4-RX and Unobtainable Brembo new GP4 caliper

BMW Alpina

FOUNDING Member & Administrator
Staff member
i know it’s an older post, but, thinking of upgrade. what is the piston size for this ?
Hi Tsaico, they are 32 and 36mm piston, so you will need RCS19 brake MC (larger than Stylema/GP4-MS Caliper which can use stock MC or RCS17)
 

Tsaico

FOUNDING Member
Hi Tsaico, they are 32 and 36mm piston, so you will need RCS19 brake MC (larger than Stylema/GP4-MS Caliper which can use stock MC or RCS17)
Thanks! BMW Alpina! You are life saver! Ok, I might want to get the gp4-ms then….anyway I can source the 30mm titanium drilled piston from brembo?
 

BMW Alpina

FOUNDING Member & Administrator
Staff member
Thanks! BMW Alpina! You are life saver! Ok, I might want to get the gp4-ms then….anyway I can source the 30mm titanium drilled piston from brembo?
Hi Tsaico,
I am not sure if you can source the 30mm Titanium Drilled Piston from Brembo, but you can buy it from Ducati Kaemna in Germany and here is the link: Tuning-Teile kaufen und Tuning Tips | Ducati & Aprilia-Tuning Kämna
I buy my Pistal forged (engine piston) for my Ducati 998 with 999S overbore engine project also from Ducati Kaemna so I can vouch for their good service. What funny was, I also was researching for the titanium drilled piston for my own GP4-MS that I ordered for my 998 project just 2 days ago 😁
You can also buy the stainless steel piston from BrakeTech for the GP4-MS as a lower cost alternative to this Titanium Drilled Piston.
 

Tsaico

FOUNDING Member
Hi Tsaico,
I am not sure if you can source the 30mm Titanium Drilled Piston from Brembo, but you can buy it from Ducati Kaemna in Germany and here is the link: Tuning-Teile kaufen und Tuning Tips | Ducati & Aprilia-Tuning Kämna
I buy my Pistal forged (engine piston) for my Ducati 998 with 999S overbore engine project also from Ducati Kaemna so I can vouch for their good service. What funny was, I also was researching for the titanium drilled piston for my own GP4-MS that I ordered for my 998 project just 2 days ago 😁
You can also buy the stainless steel piston from BrakeTech for the GP4-MS as a lower cost alternative to this Titanium Drilled Piston.
I am very grateful for this! Should I go to billet master? As I’m upgrading to MS ….
 

BMW Alpina

FOUNDING Member & Administrator
Staff member
I am very grateful for this! Should I go to billet master? As I’m upgrading to MS ….
It depend on your budget so the RCS19 Corsa Corta (buy the Corsa Corta version because it is the latest model and not just the RCS19), is a FORGED design then finish with extra machining.
While the Billet version is fully machine from the start.
In term of simple rigidity, I actually believe the FORGED is more rigid than a Billet, however, the pure billet design might be more precise (smoothness etc)...
The Billet is also more RACE because it no longer have built in rear brake light switch like the RCS19 Corsa Corta.
I actually prefer the RCS19 Corsa Corta because of the "SHAPE" of the body and the more adjustability, oh and the build in rear brake light switch.
But the billet might give you better feel during hard braking in a race track...
Still, if you want a billet master cylinder, maybe it's better if you buy the GP4-RR brake caliper instead which came with the Titanium piston.
Then buy the new Motocorse lower billet caliper mount for the ohlins fork with 108mm spacing so you can just plug and play this GP4-RR 108mm bolt spacing.
Or buy the GP4-RR with 100mm bolt spacing but spaced the rotor out, I believe 2.5mm (or 5mm) I forgot now... need to check again.
Thanks from Howard
 

Tsaico

FOUNDING Member
Hi Tsaico,
I am not sure if you can source the 30mm Titanium Drilled Piston from Brembo, but you can buy it from Ducati Kaemna in Germany and here is the link: Tuning-Teile kaufen und Tuning Tips | Ducati & Aprilia-Tuning Kämna
I buy my Pistal forged (engine piston) for my Ducati 998 with 999S overbore engine project also from Ducati Kaemna so I can vouch for their good service. What funny was, I also was researching for the titanium drilled piston for my own GP4-MS that I ordered for my 998 project just 2 days ago 😁
You can also buy the stainless steel piston from BrakeTech for the GP4-MS as a lower cost alternative to this Titanium Drilled Piston.
bought the TiN drilled piston. Interesting enough, other shops in Germany claimed 4 weeks of lead time, so I bought it from Ducati Kaemna. Thanks for the pointer again!

im Testing out a theory about stainless steel vs. aluminum (OEM) vs. TiN material to Brembo seals. Will report back.
 

BMW Alpina

FOUNDING Member & Administrator
Staff member
GP4-RR vs GP4-MS comparo 🥳:


USP deliver my Brembo GP4-MS caliper for my 998 project today so I can compare it with my GP4-RR 🧐🧐🧐:
IMG_6494.JPG


The GP4-RR is SLIMMER than the GP4-MS:
IMG_6490.JPG


So for my Panigale V4 25° Anniversario 916, I choose the Polestar Gold color for the GP4-RR to make it look a bit "retro" because it is a modern bike...
while for the 998, I choose the Nickel Polish look of the GP4-MS hoping to make it have "younger" look 🤣:
IMG_6491.JPG


More comparo pictures 🤓:
IMG_6492.JPGIMG_6493.JPG
 
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