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Discussion Starter · #1 ·
Are the stock OEM calipers installed on 2011-2021 GSX-R 750 ( in France and maybe in Europe , the GSX-R 750 is not imported / sold anymore since 2016 ) and 2012-2016 GSX-R 1000, some M4 Brembo calipers ?

For a while , i have thought the braking calipers on these years of GSX-R 750 and 1000, or at least on the 1000 and at least on the front wheel ( as i think on the rear wheel the rear caliper is a Nissin on the 2012-2016 GSX-R 1000 ; correct me if i am wrong ) , were some Brembo M4 but recently , a seller in a web shop'selling mostly motorcycle Racing equipment ( and they also have had a racing team for several years and won several titles , being several times on the podium ) , told me these GSX-Rs OEM stock calipers were nit M4 but much more basic ones !

Whereas i knew i had read somewhere they were M4 and now i remeber were i read it , on the Brembo website !
As far as i can read here ( see link bellow ) they say :

" The Suzuki GSX-R1000 remains true to the Brembo M4.32 radial caliper, a monobloc caliper with four 32 mm pistons and a 108 mm inter-axle."


For me , this means that if the GSX-R 1000 stays true to the Brembo M4 Calipers in 2016 ( the article dates from 2016) , that should mean that they have been using the M4 before that and for a while !
That said , they say " GSX-R 1000" but do not speak about GSX-R 750 !

In the article, they speak about the new 2017 ZX-10R which will use some M50 : ,
" Kawasaki's new ZX-10RR (MY 2017) is equipped with Brembo M50 monobloc caliperswith four 30 mm pistons, 320 mm stainless steel and aluminium Brembo discs,a 7-spoke aluminium front wheel forged by Marchesini, with coloured rims. Furthermore, Brembo and Kawasaki jointly developed the new BRM11H brake pad compound for the ZX 10-RR."

And about The new 2017 CBR1000R which will use M4 calipers :
" For the new CBR1000RR Fireblade (MY 2017), Brembo supplies the M4-30/32 front brake caliper and the aluminium forged front wheel, a 7-spoke Marchesini with coloured rims."

But for Suzuki , they don't speak about the new 2017 GSX-R 1000, what could lead us to think they speak about the actual model , which at that time was the 2012-2016 version of the GSX-R 1000.

So are those OEM/ stock calipers on the 2012-2016 GSX-R 1000 , on the front wheel ( and maybe on the 2011-2016 and on GSX-R 750 ) , some real M4 calipers ?
 

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Discussion Starter · #5 ·
Searching for some other infos about the stock 2011-2022 Brembo M4 made for Suzuki GSX-Rs of these generations i found on Brembo website ( among other websites ) , the information that the M4 made for GSX-Rs have 32mm pistons , whereas the aftermarket Brembo M4 have some 34mm pistons .

" The Suzuki GSX-R1000 remains true to the Brembo M4.32 radial caliper, a monobloc caliper with four 32 mm pistons and a 108 mm inter-axle. "


Also, some website selling pistons in Stainless Steel or Titanium, to replace the stock aluminium ones , specify the pistons they sell for the M4 calipers of those GSX-Rs , are 32mm.


 

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The stock calipers are not m4 for sure.
The casting molds themselves are different and the quality of the cast just isnt made to the same quality.
The stock brembos are actually lighter than the m4s but not by much.
Their performance on track isn't on par with the m4 with some inconsistency and not really fade but similar when hot.
Both use the same pads though. I thought that was interesting.

I am a big fan of the M4's personally. But have moved on to the billet ones. Not sure if the return on these are worth it yet...

M4's with ti pistons... never tried but...
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Discussion Starter · #7 · (Edited)
Post 2010 GSX-R's M4 ( starting in 2011 on the GSX-R 750 ) are not the Aftermarket Brembo M4 Racing , they are what Brembo manufactured forSuzuki, for the GSX-R 750 & 1000 , starting in 2011 , based on the Brembo aftermarket M4 design , so yes , technicaly they are not exactly the same, don't have the same piston's size and are not built exactly the same.

From what i saw on the net , Brembo had already built some calipers based / inspired by their aftermarket M4 , in 2007-2008 , for the Kawasaki Z1000.
Those didn't look and were not built exactly the same way ( i don't know what was the size of the pistons inside) as the aftermarket Brembo M4 either and were also different from the GSX-R ones .

First picture ( just bellow) is the aftermarket Brembo M4 caliper with 34mm pistons.
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That Second picture just bellow is the one made for Suzuki GSX-Rs.
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On this third picture bellow, is the one made for the 2007-2008 Kawasaki Z1000 .
The sentence at the top of that picture does not relate to the Picture, it is about true aftermarket M4 but it is the sentence at the bottom which describes which type of M4 design based calipers is on the picture .
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Discussion Starter · #8 ·
I don't doubt there are better calipers than the stock post 2010 GSX-R's style ( inspired ) M4 including the Breambo aftermarket ones but here is a post ( post #8 in that topic bellow on gixxer.com , i put the link to ) , i had found interesting , in a topic asking what to upgrade on a 2012-2016 GSX-R 1000 , for track use :
https://www.gixxer.com/threads/what-.../#post-9624709

A guy posted a video of ASBK 2013 Championship Winning Suzuki GSX-R1000 ( and one other video at least about that ) , writing this above the video link ( that i posted here , bellow what he had wrote first ) :

" Here's a great run down of the 2013 ASBK Championship Winning GSX-R1000 with 218HP...... at the back wheel, while maintaining the vast majority of OEM parts, including OEM Brake Calipers and OEM Disks stipulated within the ASBK rules at the time to keep cost down.

This bike also held the Phillip Island lap record in ASBK from the 5th Oct 2013 with a qualifying time of 1.32.274 for a few years, even after the introduction of all new L7 in 2017.

Just shows how capable the 2012 - 2016 bike was with a pro ASBK rider. "


In that post , he also wrote ( posting that other video after ) :

" Here's an Awesome front wheel cam showing the Suzuki OEM Front Brake Calipers and OEM front Disks on a 2012 ASBK GSX-R1000 during an ASBK race at Phillip Island from pole and winning the race.

BTW....These are the same calipers that " some " people on this forum over the years try calling " Fake Brembos " which is Complete BS... as shown by this video.

Back to Back ASBK Championship wins in 2012 and 2013 on stock OEM calipers and OEM disks. Fact...

Are there better calipers out there Yes... do the OEM ones get the job done Yes...

Most average Joe riders could never ride as fast as a pro rider around Phillip Island anyway, even with their Trick Fancy Calipers. "

He wrote more in his post and those who want to read all his post can check the link of the topic but i copied here what i found the most interesting .

Obviously , not everybody has the riding skills of this ASBK pilot but it's just showing what a nearly stock 2012-2016 GSX-R 1000 can give , with stock Brembo M4 style calipers ( and many other stock parts) , in the hands of a pro ASBK pilot !
 

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Their rules don't allow them to change calipers and discs...
If they did, I would guarantee they would.

Just because it gets the job done doesn't mean that better feeling calipers aren't worth it.
I can feel the difference on track (and when I practice hard braking from high speeds) that makes braking more consistent and comfortable for me. That's enough a reason to change. I need the brakes to feel the best for me.

But for most people you are correct. Stock is more than adequate. When you are braking from 30-60mph, yeah no difference.

But I'll put it this way... I would change aspects of the stock braking system before I touch the stock suspension. Geometry changes not included.
 

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I do have to say that changing to the larger piston M4 calipers, the travel on the stock oem 17mm master was too much for my tastes.
A switch to 19x18 brembo and M4 calipers was my sweet spot in terms of feel and power and lever travel. My favorite combo so far with vesrah xx pads.
Yes, it can get expensive in a hurry.
 

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Discussion Starter · #11 ·
Their rules don't allow them to change calipers and discs...
If they did, I would guarantee they would.

Just because it gets the job done doesn't mean that better feeling calipers aren't worth it.
I can feel the difference on track (and when I practice hard braking from high speeds) that makes braking more consistent and comfortable for me. That's enough a reason to change. I need the brakes to feel the best for me.

But for most people you are correct. Stock is more than adequate. When you are braking from 30-60mph, yeah no difference.

But I'll put it this way... I would change aspects of the stock braking system before I touch the stock suspension. Geometry changes not included.
Obviously in the SuperStock racing they have to use the motorbikes nearly stocks but when you see that that guy , with stock calipers on this bike held the Phillip Island lap record in ASBK from the 5th Oct 2013 with a qualifying time of 1.32.274 for several years, even after the introduction of all new L7, it shows how far the pilot riding this bike can get from some stock calipers like that whereas most other non professional pilots wouldn't have even approach with much better calipers .
Tat said, obviously , he would certainly have had an even better time with better calipers or even a Superbike level motorbike .
 

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Discussion Starter · #12 · (Edited)
I do have to say that changing to the larger piston M4 calipers, the travel on the stock oem 17mm master was too much for my tastes.
A switch to 19x18 brembo and M4 calipers was my sweet spot in terms of feel and power and lever travel. My favorite combo so far with vesrah xx pads.
Yes, it can get expensive in a hurry.
From what i read , what's the most important to get the front MC adapted to the front brake calipers piston's size is the ratio between the surface of the MC 's piston compared to the surface of all the front brake calipers' pistons .
From what i read , depending on the sources , some say it has to be the closest to 24 , while other say it must be between 24 and 27 .
To calculate the surface of a circle it is : 3,1416( diameter squared ) divided by 4
So, for a 34 mm calipers' pistons, it is 3,1416 (34 x 34 ) /4 = 907,9224
the surface of all 8 pistons of the two front calipers with 34mm pistons is :
907,9224 x8 = 7263,3792 mm2
The surface of a 17mm piston is = 226,9806
The ratio then is 7263 / 226 = 32,1371 which is not good
the surface of a 19mm'piston is : 283,5294
So, the ratio when using 2 calipers with a total of 8 pistons of 34 mm with a 19 mm piston of an MC 19 is:
7263/283 =25,6643 what falls in the right numbers

All that knowing that the inter-axis number ( the second number given for an MC , like the 18 in 19x18 ) also plays a role and the smaller the inter-axis, the more bite you get in the braking whereas a bigger inter-axis, will give less bite when braking but the braking will be more easy to dose , more precise ( at least this is what i read searching for some informations about all that on the net ).
 

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From what i read , what's the most important to get the front MC adapted to the front brake calipers piston's size is the ratio between the surface of the MC 's piston compared to the surface of all the front brake calipers' pistons .
From what i read , depending on the sources , some say it has to be the closest to 24 , while other say it must be between 24 and 27 .
To calculate the surface of a circle it is : 3,1416( diameter squared ) divided by 4
So, for a 34 mm calipers' pistons, it is 3,1416 (34 x 34 ) /4 = 907,9224
the surface of all 8 pistons of the two front calipers with 34mm pistons is :
907,9224 x8 = 7263,3792 mm2
The surface of a 17mm piston is = 226,9806
The ratio then is 7263 / 226 = 32,1371 which is not good
the surface of a 19mm'piston is : 283,5294
So, the ratio when using 2 calipers with a total of 8 pistons of 34 mm with a 19 mm piston of an MC 19 is:
7263/283 =25,6643 what falls in the right numbers

All that knowing that the inter-axis number ( the second number given for an MC , like the 18 in 19x18 ) also plays a role and the smaller the inter-axis, the more bite you get in the braking whereas a bigger inter-axis, will give less bite when braking but the braking will be more easy to dose , more precise ( at least this is what i read searching for some informations about all that on the net ).
Yes...
did you know though... the area of the pistons only on one side of the caliper account for pressure transfer of the system from the master cylinder? So, lets say you apply 100 psi at the master. that 100psi is sent to all 4 pistons BUT you only take the area of 2 of the pistons to multiple by 100psi to get total force applied to the pads. It's a physics thing.

So, while your ratio calculation you found likely here Front Master Cylinder Ratio Chart is "practically" correct. The technically correct way to calculate it is with 1/2 the pistons in a fixed caliper and the corresponding ratios are smaller by 1/2. This way, you can calculate sliding calipers with the same formula as you still take the area of the piston on one side. The other side is fixed. Just something to keep in mind if comparing ratios like on the rear brake which is sliding. although the pedal ratio here is different as well as the force applied with the foot vs the hand.

I bring this up because I went with a rear caliper conversion from the oem 1 piston sliding to a 4 piston fixed caliper. To check the MC to caliper pistons ratios to make sure the difference wasn't too great, I had to use only 1/2 of the 4 pistons in the calculation NOT all 4. Remember, this is force applied not travel. It might take more travel to move 4 pistons vs 1 but the force if the ratios are the same will be equal.
 

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Discussion Starter · #14 · (Edited)
Yes...
did you know though... the area of the pistons only on one side of the caliper account for pressure transfer of the system from the master cylinder? So, lets say you apply 100 psi at the master. that 100psi is sent to all 4 pistons BUT you only take the area of 2 of the pistons to multiple by 100psi to get total force applied to the pads. It's a physics thing.

So, while your ratio calculation you found likely here Front Master Cylinder Ratio Chart is "practically" correct. The technically correct way to calculate it is with 1/2 the pistons in a fixed caliper and the corresponding ratios are smaller by 1/2. This way, you can calculate sliding calipers with the same formula as you still take the area of the piston on one side. The other side is fixed. Just something to keep in mind if comparing ratios like on the rear brake which is sliding. although the pedal ratio here is different as well as the force applied with the foot vs the hand.

I bring this up because I went with a rear caliper conversion from the oem 1 piston sliding to a 4 piston fixed caliper. To check the MC to caliper pistons ratios to make sure the difference wasn't too great, I had to use only 1/2 of the 4 pistons in the calculation NOT all 4. Remember, this is force applied not travel. It might take more travel to move 4 pistons vs 1 but the force if the ratios are the same will be equal.
I had not read anything about that .
This is not where i found the infos i wrote , because it seems the link you put is for vintage bikes with only 4 front pistons max ( unless i didn't understood something ) and many datas are for two pistons calipers , what you don't find anymore for many years on good bikes , all have two front calipers , mostly with 4 to 6 opposing pistons .
I found these infos and formulas on a French webpage ( And i also found that same formulas / infos i used , on some English websites ).

I didn't speak about sliding Calipers , i was only speaking about fixed calipers with opposing pistons .

That said , for those who want to calculate the right ratio for sliding calipers with only pistons on one side ( i suppose, mostly used on vintage motorbikes ) , what is the right formula to calculate the ratio between the MC piston and the calipers' piston , based on what you say then ?
 

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I had not read anything about that .
This is not where i found the infos i wrote , because it seems the link you put is for vintage bikes with only 4 front pistons max ( unless i didn't understood something ) and many datas are for two pistons calipers , what you don't find anymore for many years on good bikes , all have two front calipers , mostly with 4 to 6 opposing pistons .
I found these infos and formulas on a French webpage ( And i also found that same formulas / infos i used , on some English websites ).
Sry, my bad.


That said , for those who want to calculate the right ratio for sliding calipers with only pistons on one side ( i suppose, mostly used on vintage motorbikes ) , what is the right formula to calculate the ratio between the MC piston and the calipers' piston , based on what you say then ?
So, yeah... I kinda brought in a different topic about hydraulic systems into this, but I think it was sufficiently related that understanding one was key to understanding the other.

You don't really need ANOTHER formula for single sided sliding calipers as long as you correctly describe how hydraulic pressure is transferred from the master cylinder to the calipers whether sliding or fixed.

Only one side of the caliper piston area counts toward the force applied to the pads whether fixed or sliding. So a fixed caliper 34mm 2 opposed piston caliper can apply the same force on the pads as a sliding single piston 34mm caliper. (Not saying sliding caliper are equal in performance to fixed calipers, just the force you can apply is technically the same in a static system)
So in your equation, if you say you should only count 1 side of the calipers pistons (total of 4 instead of 8) and 1/2 the ratio you want (12-14) then you can apply the same formula to both sliding and fixed calipers.

But the reason is not so much to keep one formula for sliding and fixed calipers so much as to accurately describe how pressure and force is transferred in the braking system.

Sorry if I'm explaining it poorly... I was never a great teacher.
 
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