M695 single disc brake?

[cencalal]

I think speedog mentioned he ran a single 320mm rotor and 4-piston caliper for a while.  The stock brakes with EBC sintered pads work fine for me on my 695, but if a single 4-piston / 320 rotor setup would work as well or better, I might change for the weight savings.  Any comments on how this might work?  I weigh 140 and am not crazy fast on the street...

Is there a stock Brembo 320mm rotor that would fit that would have an aluminum carrier for more lightness?

Thanks

[koko64]

Oem "snowflake" disc is 320mm with alloy carrier.

[Speeddog]

To fit a single rotor setup, you'll need everything; master, line, rotor and caliper.
None of your existing stuff is applicable.

I ran a single-rotor setup on my shop bike, a '98 M750, and I weigh 180 lbs no gear.

I started with a 'snowflake' rotor, brand new, running Ferodo CP211 pads in a 4-pad caliper.
16mm goldline small-pivot master, as that's what I had as a spare.
Lever was rock hard and effort was too high.

Swapped to a 13mm big-pivot master.
Lever was a bit soft for my taste, effort was fine.

Rotor worn below minimum after 24k miles.

Swapped in a BrakeTech iron rotor and some new CP211 pads, ran it for 7k miles.
About 40% of thickness gone, so predicted life of ~18k miles.

Never had any issue with braking power with either configuration.

Do *not* take the above noted service life numbers as anything close to gospel, nor compare the Snowflake to Braketech as apples:apples.
The Brembo saw 18k of easy freeway commuting with minimal traffic, the balance was weekend fun riding.
The BrakeTech saw nearly all weekend fun riding.
YMMV.

I took the single rotor setup out of service due to starting fairly regular 2-up riding.
Not enough power margin to satisfy my comfort level 2-up.

If I were to re-fit a single disc setup.....
I'd use a 13mm goldline small-pivot, as they've got a bit less advantage in the lever geometry.
So the lever would be harder, and the slight increase in effort would still be fine.
If budget was no concern, I'd go a 330mm iron rotor to get that squeech more power over the 320mm.
But that would require an adapter bracket to move the caliper out that 5mm.

Single disc does save ~5lbs, all of it unsprung weight, and about half of it rotating weight as well.
The only way to acheive that kind of difference another way would be replacing the 3-spoke front wheel with a BST carbon.
There would be more benefit as it's all rotating weight, but it's way more money.

[koko64]

Diminshing returns per dollar can sure happen. My buddy on his 620 says with good pads and a well bled system that his stops very well when street riding. I have seen some 4 pot caliper upgrades here too, but if you are on a mission to lose weight it can cost.

[cencalal]

I was wondering about the 16mm (if I'm not mistaken) 695 coffin style master.  Would like to keep it as it's polished lid matches the clutch master, and was thinking that if it's pushing four pistons, two on each side, it could just as well push four on one side.  But the ratio of surface area, master to caliper pistons, is what makes the "feel".  Smaller master piston, less lever effort, but possibly too soft.

I was going to use a 4-piston 2-pad caliper, but is a four pad better? Year/model?  And what model uses a snowflake 320 rotor?  Is that the only 320 mm 6-bolt Brembo rotor with aluminum carrier?  I'd be sourcing these parts used from ebay.

Lotsa questions, but this is my first Ducati and I don't know the parts applications.  Several pounds of unsprung weight, some of it rotating, would be great to lose. 

[Speeddog]

Yes, your OEM setup is pushing 4 pistons, 2 on each side.
But the caliper bodies are floating, not fixed, so it requires the same master cylinder size as 2 four-piston fixed body calipers.

You could get a 13mm coffin master, and fit your polished lid.

4-pad caliper has more power, as it's 4 of 34mm diameter pistons, as opposed to the 2 of 30mm and 2 of 34mm on a standard 2-pad caliper.
And the 4-pad has more 'servo' power from the 4 small pads.
749/999 SBK had the 4-pad calipers.

Lots of Monsters ran with one rotor and a single 2-pad calipers.
It's the lightest and lowest cost setup.

Later 748, 996, S4, S4R, ST3s and ST4s had snowflakes.
Keep in mind, all of those bikes are ~15 years old, so there's lots of other stuff that they could have been fitted with in the meantime.

At your weight, a 2-pad caliper with the most aggressive pads would likely be OK.

[stopintime]

Your 695 master is 15 mm 

[cencalal]

Looks like a single disc 13mm master was on the '02 M620 dark and others?  Are there marks or numbers indicating bore size?

I've sourced a new Ferodo rotor and clean used caliper on ebay - might try them with my 695 master to see how it feels...

[stopintime]

AFAIK there is a stamped number on the master (under?).

No harm in testing your current master and see what you think.

[ducpainter]

AFAIK there is a stamped number on the master (under?).

No harm in testing your current master and see what you think.

Correct...

and it will feel like a brick.