801 320mm brake discs

I changed my rotors to 320mm and there was a difference. The bigger difference was when I swapped on some Brembo calipers I had laying around from a Ducati monster. I’m sure if I did sintered pads it would be even bigger but it’s 2 finger braking with whatever pads were stock on a monster.
 
Actionabe said:
I changed my rotors to 320mm and there was a difference. The bigger difference was when I swapped on some Brembo calipers I had laying around from a Ducati monster. I’m sure if I did sintered pads it would be even bigger but it’s 2 finger braking with whatever pads were stock on a monster.
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If I remember correctly, you changed the discs to some stock 1290 KTM/Galfer 320mm discs.
I read somewhere that the stock KTM/Galfer brake discs are all produced on a separate production line and aren't of particularly good quality.
The aftermarket Galfer discs, on the other hand, are apparently of much higher quality; comparable to the aftermarket Brembo discs.
That might be a reason why the brake calipers made a bigger difference for you.

A few years ago, I also replaced some original brake discs on another bike with a pair of Brembo Oro discs and Brembo sintered pads; although the Brembo discs were identical in size to the originals, the difference was nonetheless very significant.

Those are just some experiences I’ve had; others, however, may have had different experiences...
 
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Yeah they are 1290 rotors. I am running stock dual 701 galfer discs on my 701’s mag wheel set up. They work great but do seem to be noisier than normal. They feel a lot different than the 1290s..
 
I am not skilled enough, but ... if I use for example Brembo M4.32, these calipers are same dimensions and same diameter of brake cylinders (pistons) as the original JJ. So they would brake "the same", no? Or? Where should the better braking come from??
If I will fit some M50, it will have bigger diameter of the cylinders, which means, that there will much longer lever movement on the master pump, no? But brake better, this is clear.

I was surprised, that 300=>320 discs will make just 6,7% difference of stopping power ... due to my mathematics :-D
 
animals21 said:
I am not skilled enough, but ... if I use for example Brembo M4.32, these calipers are same dimensions and same diameter of brake cylinders (pistons) as the original JJ. So they would brake "the same", no? Or? Where should the better braking come from??
If I will fit some M50, it will have bigger diameter of the cylinders, which means, that there will much longer lever movement on the master pump, no? But brake better, this is clear.

I was surprised, that 300=>320 discs will make just 6,7% difference of stopping power ... due to my mathematics :-D
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6.7% is the difference between breaking on time ore not, hehehe.

I am not skilled neither but I guess the Brembo M4 will be more rigid therefore loosing less power and you will probably feel it in the initial bite. I guess they will also handle better the heating when breaking hard.

For me the original JJs are good enough for street but I do not like the initial bite, it is too progressive. Perhaps changing the master cylinder will have more direct impact in braking power.
 
I'm not 100% sure about the 801 calipers; but my guess is they are like the Duke 790 calipers; 2x 30mm and 2x 34mm pistons; (the 801 and 790 brake-master-cylinders are identical). The Brembo M50 calipers and the Stylema calipers are 4x 30mm pistons.
 
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None of this is really about braking power, it is about having more thermal overhead. Unless you are tracking your bike going to other calipers or larger rotors is simply not necessary - the brakes are sufficient to lock up the tire so there is more stopping force available than traction. However there appears to be some issue with the metallurgy of the stock rotors and they way the are prone to warping, so that is a reason to switch. The fact that you can get larger rotors that save 1kg each is another. Looking cool like a racer is a third. If you just don't like the initial bite switch pads and save hundreds of dollars over calipers.
 
@animals21, I do agree with @toast449. The braking system as a whole is somewhat more complex; it involves the piston size of the calipers, the volume of brake fluid that must be moved/pumped within the system and the calipers; and also the brake master cylinder which must be matched to the calipers and the system.
The main advantage of the latest generation of Brembo calipers lies primarily in reduced weight, better heat dissipation, and (reportedly) greater rigidity; while all of this may be relevant for racing or intensively track use, it's somewhat questionable whether it is truly significant for street riding…
What I said before, to me it's still the different to stock materials of the discs and pads that make the difference; the 320mm instead of the 300mm is just a nice addition.

By the way; if someone is (for whatever reason) looking for even more weight reduction; the 300mm Galfer DF-801-CF, that is listed to fit the Duke 790 is just 1175gr / the 320mm Galfer DF-787-CW is 1380gr; the 320mm Brembo Oro 78B408B0 is 1620gr; the 300mm stock KTM-Galfer is 1858gr.

DF801CW.jpg
 
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